2017 NEC Significant Code Changes Part 5

Transcription

1 2017 NEC Significant Cde Changes Part 5 Fur (4) Cntinuing Educatin Hurs Curse Apprval #EE1005 Apprved Cntinuing Educatin fr Prfessinal Engineers 2017 NEC Significant Cde Changes Part 5 i

2 Table f Cntents 2017 NEC Significant Cde Changes Part 5 Intrductin... 1 Chapter 7: Special Cnditins... 2 Article 700 Emergency Systems... 2 Article 701 Legally Required Standby Systems... 4 Article 702 Optinal Standby Systems... 5 Article 705 Intercnnected Electric Pwer Prductin Surces... 5 Article 706 Energy Strage Systems... 6 Article 708 Critical Operatins Pwer Systems (COPS) Article 710 Stand-Alne Systems Article 712 Direct Current Micrgrids Article 725 Class 1, Class 2, and Class 3 Remte-Cntrl, Signaling, and Pwer-Limited Circuits Article 727 Instrumentatin Type Cable: Type ITC Article 760 Fire Alarm Systems Article 770 Optical Fiber Cables and Raceways Chapter 8: Cmmunicatins Systems Article 810 Radi and Televisin Equipment Article 840 Premises-Pwered Bradband Cmmunicatins Systems Chapter 9: Tables and Annex D Quiz Questins NEC Significant Cde Changes Part 5 ii

3 2017 NEC Significant Cde Changes Part 5 LEARNING OBJECTIVES Upn cmpletin f this curse the student will be able t: 1. Becme familiar with sme f the significant changes including additins, deletins, and mdificatin t the 2017 Editin f NFPA 70: Natinal Electrical Cde (NEC) frm the 2014 Editin 2. Cmprehend, after reviewing the significant changes and additins t the 2017 Editin f NFPA 70: Natinal Electrical Cde (NEC) the large scpe f the changes t the cde, thereby seeking additinal and mre thrugh reviews f the entire cde, fllwing cmpletin f this curse. INTRODUCTION Every three years, the Natinal Electrical Cde (NEC ) is revised and expanded. Initially the NFPA received 4,012 public suggestins fr changes, which resulted in 1,235 first revisins. There were 1,513 public cmments submitted in respnse t these 1,235 first revisins, resulting anyne participating in the electrical industry t get up t speed with all the changes. What t Expect In this curse the student will be presented an verview f the mst significant changes fund in the 2017 NEC. This is part 1 f a series f curses cvering the changes and will prgress thrugh each chapter and its articles presenting the many imprtant changes. The changes will be highlighted fr easy recgnitin and a shrt synpsis f the reasn fr the change is presented as well. in 559 secnd revisins. Changes included editrial clarificatin, expanded requirements, new requirements, deleted requirements, and the relcatin f ther requirements. Nine new articles were prpsed, and five new articles were added t the 2017 NEC. With the fast pace f technlgy, it s mre imprtant than ever fr 2017 NEC Significant Cde Changes Part 5 1

4 Large-Scale Phtvltaic (PV) Electric Pwer Prductin Facility (New Article 691) cvers systems that prduce at least 5 megawatts (MW) f pwer, r enugh t pwer 800+ U.S. hmes. Energy Strage Systems (New Article 706) gverns ESS installatin, discnnectin, shutdwn, and safety labeling. Stand-Alne Systems (New Article 710) cvers pwer prductin surces that are nt cnnected t the grid, including PV and wind-pwered systems. Direct Current Micrgrids (New Article 712) cncerns independent energy distributin netwrks that allw the utilizatin f pwer frm dc surces t direct-current lads. Micrgrids are n the rise wrldwide CHAPTER 7: SPECIAL CONDITIONS ARTICLE 700 Emergency Systems and Branch Circuit Emergency Lighting Transfer Switch Definitins. (Emergency Systems) Branch Circuit Emergency Lighting Transfer Switch. A device cnnected n the lad side f a branch circuit vercurrent prtective device that transfers nly emergency lighting lads frm the nrmal supply t an emergency supply. Infrmatinal Nte: See ANSI/UL 1008, Transfer Switch Equipment, fr infrmatin cvering branch circuit emergency lighting transfer switches Branch Circuit Emergency Lighting Transfer Switch. Emergency lighting lads supplied by branch circuits rated at nt greater than 20 amperes shall be permitted t be transferred frm the nrmal branch circuit t an emergency branch circuit using a listed branch circuit emergency lighting transfer switch. The mechanically held requirement f 700.5(C) shall nt apply t listed branch circuit emergency lighting transfer switches. Reasn fr the Change A new titled, Branch Circuit Emergency Lighting Transfer Switch was added t allw these devices t be used t transfer emergency lighting lads supplied by branch circuits rated at nt greater than 20 amperes frm the nrmal branch circuit t an emergency branch circuit. A new definitin fr Branch Circuit Emergency Lighting Transfer Switch was als added at (F) Temprary Surce f Pwer fr Maintenance r Repair f the Alternate Surce f Pwer Tests and Maintenance (F) Temprary Surce f Pwer fr Maintenance r Repair f the Alternate Surce f Pwer. If the emergency system relies n a single alternate surce f pwer, which will be disabled fr maintenance r repair, the emergency system shall include permanent switching means t cnnect a prtable r temprary alternate surce f pwer, which shall be available fr the duratin f the maintenance r repair. The permanent switching means t cnnect a prtable r temprary alternate surce f pwer shall cmply with the fllwing: 1. Cnnectin t the prtable r temprary alternate surce f pwer shall nt require mdificatin f the permanent system wiring NEC Significant Cde Changes Part 5 2

5 2. Transfer f pwer between the nrmal pwer surce and the emergency pwer surce shall be in accrdance with The cnnectin pint fr the prtable r temprary alternate surce shall be marked with the phase rtatin and system bnding requirements. 4. Mechanical r electrical interlcking shall prevent inadvertent intercnnectin f pwer surces. 5. The switching means shall include a cntact pint that shall annunciate at a lcatin remte frm the generatr r at anther facility mnitring system t indicate that the permanent emergency surce is discnnected frm the emergency system. It shall be permissible t utilize manual switching t switch frm the permanent surce f pwer t the prtable r temprary alternate surce f pwer and t utilize the switching means fr cnnectin f a lad bank. Infrmatinal Nte: There are many pssible methds t achieve the requirements f 700.3(F). See Figure 700.3(F) fr ne example. Figure 700.3(F) Exceptin: The permanent switching means t cnnect a prtable r temprary alternate surce f pwer, fr the duratin f the maintenance r repair, shall nt be required where any f the fllwing cnditins exists: 1. All prcesses that rely n the emergency system surce are capable f being disabled ) during maintenance r repair f the emergency surce f pwer. 2. The building r structure is unccupied and fire suppressin systems are fully functinal and d nt require an alternate pwer surce. 3. Other temprary means can be substituted fr the emergency system. 4. A permanent alternate emergency surce, such as, but nt limited t, a secnd n-site standby generatr r separate electric utility service cnnectin, capable f supprting the emergency system, exists. Reasn fr the Change A new first level subdivisin is titled, Temprary Surce f Pwer fr Maintenance r Repair f the Alternate Surce f Pwer was added at 700.3(F) calling fr emergency systems that rely n a single alternate surce f pwer t include a permanent switching means t cnnect a prtable r temprary alternate surce f pwer while the single alternate surce f pwer is disabled fr maintenance r repair. This permanent switching means must be available fr the duratin f the maintenance r repair. This new requirement cmes with an exceptin with fur cnditins (E) Transfer Equipment (Emergency Systems) Transfer Equipment (Emergency Systems) (E) Dcumentatin. The shrt-circuit current rating f the transfer equipment, based n the specific vercurrent prtective device type and settings prtecting the transfer equipment, shall be field marked n the exterir f the transfer equipment. Reasn fr the Change A new requirement was added at 700.5(E) that will nw require the shrt-circuit current rating f the transfer equipment t be field marked n the exterir f the transfer equipment. This shrt-circuit current rating will be based n the specific vercurrent prtective device type and settings prtecting the transfer equipment NEC Significant Cde Changes Part 5 3

6 700.10(A) Wiring, Emergency System Wiring, Emergency System. (A) Identificatin. Emergency circuits shall be permanently marked s they will be readily identified as a cmpnent f an emergency circuit r system by the fllwing methds: (1) All bxes and enclsures (including transfer switches, generatrs, and pwer panels) fr emergency circuits shall be permanently marked s they will be readily identified as a cmpnent f an emergency circuit r system. (2) Where bxes r enclsures are nt encuntered, expsed cable r raceway systems shall be permanently marked t be identified as a cmpnent f an emergency circuit r system, at intervals nt t exceed 7.6 m (25 ft). Receptacles supplied frm the emergency system shall have a distinctive clr r marking n the receptacle cver plates r the receptacles. Reasn fr the Change In additin t bxes and enclsures, these identificatin requirements have been expanded t expsed emergency system cables and raceway systems nt assciated with junctin bxes r enclsures. Receptacles supplied frm the emergency system are nw required t be identified by a distinctive clr r marking n the receptacle cver plates r the receptacle (D) Wiring, Emergency System Wiring, Emergency System. (D) Fire Prtectin. Emergency systems shall meet the additinal requirements in (D)(1) thrugh (D)(3) in assembly ccupancies fr nt less than 1000 persns r in buildings abve 23 m (75 ft) in height. the fllwing ccupancies: (1) Assembly ccupancies fr nt less than 1000 persns (2) Buildings abve 23 m (75 ft) in height. (3) Health care ccupancies where persns are nt capable f self preservatin (4) Educatinal ccupancies with mre than 300 ccupants Reasn fr the Change Fire prtectin prvisins fr emergency system feeders were expanded t als include health care ccupancies where persns are nt capable f self-preservatin and educatinal ccupancies with mre than 300 ccupants (in additin t high-rise buildings and thse buildings with large ccupancy lads). ARTICLE 701 Legally Required Standby Systems 701.6(D) Signals. (Legally Required Standby Systems) Signals. (Legally Required Standby Systems) Audible and visual signal devices shall be prvided, where practicable, fr the purpses described in 701.6(A), (B), (C), and (D). (D) Grund Fault. T indicate a grund fault in slidly grunded wye, legally required standby systems f mre than 150 vlts t grund and circuit-prtective devices rated 1000 amperes r mre. The sensr fr the grundfault signal devices shall be lcated at, r ahead f, the main system discnnecting means fr the legally required standby surce, and the maximum setting f the signal devices shall be fr a grund-fault current f 1200 amperes. Instructins n the curse f actin t be taken in event f indicated grund fault shall be lcated at r near the sensr lcatin. Fr systems with multiple emergency surces cnnected t a paralleling bus, the grund fault sensr shall be permitted at an alternate lcatin. Infrmatinal Nte: Fr signals fr generatr sets, see NFPA , Standard fr Emergency and Standby Pwer Systems. Reasn fr the Change Cde language was added t allw the grund-fault sensr t be lcated at an alternate lcatin fr systems with multiple emergency surces cnnected t a paralleling bus NEC Significant Cde Changes Part 5 4

7 ARTICLE 702 Optinal Standby Systems (C) Pwer Inlets Rated at 100 Amperes r Greater, fr Prtable Generatrs Outdr Generatr Sets. (Optinal Standby Systems) (A) Permanently Installed Generatrs and Prtable Generatrs Greater Than 15 kwand Permanently Installed Generatrs. (C) Pwer Inlets Rated at 100 Amperes r Greater, fr Prtable Generatrs. Equipment cntaining pwer inlets fr the cnnectin f a generatr surce shall be listed fr the intended use. Systems with pwer inlets shall be equipped with an interlcked discnnecting means. Exceptin N. 1: If the inlet device is rated as a discnnecting means. Exceptin N. 2: Supervised industrial installatins where permanent space is identified fr the prtable generatr lcated within line f sight f the pwer inlets shall nt be required t have interlcked discnnecting means nr inlets rated as discnnects. Reasn fr the Change New language was added requiring ptinal standby equipment cntaining pwer inlets rated 100 amperes r mre fr the cnnectin f a generatr surce t be listed fr the intended use and be equipped with an interlcked discnnecting means. Tw exceptins have been added after this new language t address instances where the inlet has been rated as a discnnecting means and fr supervised industrial installatins where permanent space has been identified fr the prtable generatr t be lcated within line f sight f the pwer inlets. ARTICLE 705 Intercnnected Electric Pwer Prductin Surces Article 705, Part IV Micrgrid Systems System Operatin. Micrgrid systems shall be permitted t discnnect frm the primary surce f pwer r ther intercnnected electric pwer prductin surces and perate as a separate micrgrid system Primary Pwer Surce Cnnectin. Cnnectins t primary pwer surces that are external t the micrgrid system shall cmply with the requirements f Recnnectin t Primary Pwer Surce. Micrgrid systems that recnnect t primary pwer surces shall be prvided with the necessary equipment t establish a synchrnus transitin Micrgrid Intercnnect Devices (MID). Micrgrid intercnnect devices shall cmply with the fllwing: (1) Be required fr any cnnectin between a micrgrid system and a primary pwer surce (2) Be listed r field labeled fr the applicatin (3) Have sufficient number f vercurrent devices lcated t prvide vercurrent prtectin frm all surces Infrmatinal Nte: MID functinality is ften incrprated in an interactive r multimde inverter, energy strage system, r similar device identified fr interactive peratin. Reasn fr the Change A new Part IV was added t Article 705 titled, Micrgrid Systems. Micrgrid systems are smetimes referred t as intentinally islanded systems and standalne systems. Micrgrids are a way t add resiliency against lss f pwer in premises wiring systems NEC Significant Cde Changes Part 5 5

8 ARTICLE 706 Energy Strage Systems Article 706 Energy Strage Systems The fllwing is the new Article 706 titled, Energy Strage Systems, which was added t the NEC pertaining t all permanently installed energy strage systems (ESS) PART I. GENERAL Scpe. This article applies t all permanently installed energy strage systems (ESS) perating at ver 50 vlts ac r 60 vlts dc that may be standalne r interactive with ther electric pwer prductin surces. Infrmatinal Nte: The fllwing standards are frequently referenced fr the installatin f energy strage systems: (1) NFPA , Standard n Stred Electrical Energy Emergency and Standby Systems (2) IEEE , Recmmended Practice fr Installatin Design and Installatin f Vented Lead- Acid Batteries fr Statinary Applicatins (3) IEEE , Recmmended Practice fr Sizing Vented Lead-Acid Strage Batteries fr Statinary Applicatins (4) IEEE , Recmmended Practice fr Installatin and Maintenance f Nickel-Cadmium Batteries fr Phtvltaic (PV) Systems (5) IEEE , Recmmended Practice fr Installatin Design, and Installatin f Valve-Regulated Lead-Acid Batteries fr Statinary Applicatins (6) IEEE , Recmmended Practice fr Statinary Battery Electrlyte Spill Cntainment and Management (7) IEEE 1635/ASHRAE , Guide fr the Ventilatin and Thermal Management f Statinary Battery Installatins Batteries fr Statinary Applicatins (8) UL 810A, Electrchemical Capacitrs (9) UL 1973, Batteries fr Use in Light Electric Rail (LER) Applicatins and Statinary Applicatins (10) UL 1989, Standard fr Standby Batteries (11) UL Subject 2436, Spill Cntainment fr Statinary Lead Acid Battery Systems (12) UL Subject 9540, Safety f Energy Strage Systems and Equipment Definitins. Battery. Tw r mre cells cnnected tgether electrically in series, in parallel, r a cmbinatin f bth t prvide the required perating vltage and current levels. Cell. The basic electrchemical unit, characterized by an ande and a cathde, used t receive, stre, and deliver electrical energy. Cntainer. A vessel that hlds the plates, electrlyte, and ther elements f a single unit, cmprised f ne r mre cells, in a battery. It can be referred t as a jar r case. Diversin Charge Cntrller. Equipment that regulates the charging prcess f an ESS by diverting pwer frm energy strage t directcurrent r alternating-current lads r t an intercnnected utility service. Electrlyte. The medium that prvides the in transprt mechanism between the psitive and negative electrdes f a cell. Energy Strage System (ESS). One r mre cmpnents assembled tgether capable f string energy fr use at a future time. ESS(s) can include but is nt limited t batteries, capacitrs, and kinetic energy devices (e.g., flywheels and cmpressed air). These systems can have ac r dc utput fr utilizatin and can include inverters and cnverters t change stred energy int electrical energy. Energy Strage System, Self- Cntained. Energy strage systems where the cmpnents such as cells, batteries, r mdules and any necessary cntrls, ventilatin, illuminatin, fire suppressin, r alarm systems are assembled, installed, and packaged int a singular energy strage cntainer r unit NEC Significant Cde Changes Part 5 6

9 Infrmatinal Nte: Self-cntained systems will generally be manufactured by a single entity, tested and listed t safety standards relevant t the system, and readily cnnected n site t the electrical system and in the case f multiple systems t each ther. Energy Strage System, Pre- Engineered f Matched Cmpnents. Energy strage systems that are nt selfcntained systems but instead are preengineered and field-assembled using separate cmpnents supplied as a system by a singular entity that are matched and intended t be assembled as an energy strage system at the system installatin site. Infrmatinal Nte: Pre-engineered systems f matched cmpnents fr field assembly as a system will generally be designed by a single entity and cmprised f cmpnents that are tested and listed separately r as an assembly. Energy Strage System, Other. Energy strage systems that are nt self-cntained r pre-engineered systems f matched cmpnents but instead are cmpsed f individual cmpnents assembled as a system. Infrmatinal Nte: Other systems will generally be cmprised f different cmpnents cmbined n site t create an ESS. Thse cmpnents wuld generally be tested and listed t safety standards relevant t the applicatin. Flw Battery. An energy strage cmpnent similar t a fuel cell that stres its active materials in the frm f tw electrlytes external t the reactr interface. When in use, the electrlytes are transferred between reactr and strage tanks. Infrmatinal Nte: Tw cmmercially available flw battery technlgies are zinc brmine and vanadium redx, smetimes referred t as pumped electrlyte ESS. Intercell Cnnectr. An electrically cnductive bar r cable used t cnnect adjacent cells. Intertier Cnnectr. In a battery system, an electrical cnductr used t cnnect tw cells n different tiers f the same rack r different shelves f the same rack. Inverter Input Circuit. Cnductrs between the inverter and the ESS in stand-alne and multimde inverter systems. Inverter Output Circuit. Cnductrs between the inverter and anther electric pwer prductin surce, such as a utility fr an electrical prductin and distributin netwrk. Inverter Utilizatin Output Circuit. Cnductrs between the multimde r standalne inverter and utilizatin equipment. Nminal Vltage (Battery r Cell). The value assigned t a cell r battery f a given vltage class fr the purpse f cnvenient designatin. The perating vltage f the cell r battery may vary abve r belw this value. Sealed Cell r Battery. A cell r battery that has n prvisin fr the rutine additin f water r electrlyte r fr external measurement f electrlyte specific gravity. Infrmatinal Nte: Sme cells that are cnsidered t be sealed under cnditins f nrmal use, such as valve-regulated lead acid r sme lithium cells, cntain pressure relief valves. Terminal. That part f a cell, cntainer, r battery t which an external cnnectin is made (cmmnly identified as a pst, pillar, ple, r terminal pst) Other Articles. Wherever the requirements f ther articles f this Cde and Article 706 differ, the requirements f Article 706 shall apply. If the ESS is capable f being perated in parallel with a primary surce(s) f electricity, the requirements in 705.6, , , , , , , , and Part IV f Article 705 shall apply System Classificatin. ESS shall be classified as ne f the types described as fllws: (1) ESS, self-cntained 2017 NEC Significant Cde Changes Part 5 7

10 Infrmatinal Nte: Sme self-cntained systems may be listed. (2) ESS, pre-engineered f matched cmpnents (3) ESS, ther Equipment. Mnitrs, cntrls, switches, fuses, circuit breakers, pwer cnversin systems, inverters and transfrmers, energy strage cmpnents, and ther cmpnents f the energy strage system ther than lead-acid batteries, shall be listed. Alternatively, self cntained ESS shall be listed as a cmplete energy strage system Multiple Systems. Multiple ESSs shall be permitted t be installed in r n a single building r structure Discnnecting Means. (A) ESS Discnnecting Means. A discnnecting means shall be prvided fr all ungrunded cnductrs derived frm an ESS. A discnnecting means shall be readily accessible and lcated within sight f the ESS. Infrmatinal Nte: See (H) fr infrmatin n the lcatin f the vercurrent device fr cnductrs. (B) Remte Actuatin. Where cntrls t activate the discnnecting means f an ESS are nt lcated within sight f the system, the discnnecting means shall be capable f being lcked in the pen psitin, in accrdance with , and the lcatin f the cntrls shall be field marked n the discnnecting means. (C) Busway. Where a dc busway system is installed, the discnnecting means shall be permitted t be incrprated int the busway. (D) Ntificatin. The discnnecting means shall be legibly marked in the field. The marking shall meet the requirements f (B) and shall include the fllwing: (1) Nminal ESS vltage (2) Maximum available shrt-circuit current derived frm the ESS (3) The assciated clearing time r arc duratin based n the available shrt-circuit current frm the ESS and assciated vercurrent prtective devices if applicable (4) Date the calculatin was perfrmed Exceptin: The labeling in 706.7(D)(1) thrugh (D)(4) shall nt be required if an arc flash label is applied in accrdance with acceptable industry practice. Infrmatinal Nte N. 1: Industry practices fr equipment labeling are described in NFPA 70E- 2015, Standard fr Electrical Safety in the Wrkplace. This standard prvides specific criteria fr develping arc-flash labels fr equipment that prvides nminal system vltage, incident energy levels, arc-flash bundaries, minimum required levels f persnal prtective equipment, and s frth. Infrmatinal Nte N. 2: Battery equipment suppliers can prvide infrmatin abut shrt circuit current n any particular battery mdel. (E) Partitins and Distance. Where energy strage system input and utput terminals are mre than 1.5 m (5 ft) frm cnnected equipment, r where the circuits frm these terminals pass thrugh a wall r partitin, the installatin shall cmply with the fllwing: (1) A discnnecting means shall be prvided at the energy strage system end f the circuit. Fused discnnecting means r circuit breakers shall be permitted t be used. (2) A secnd discnnecting means lcated at the cnnected equipment shall be installed where the discnnecting means required by 706.7(E)(1) is nt within sight f the cnnected equipment. Infrmatinal Nte N. 1: Fr remte discnnect cntrls in infrmatin technlgy equipment rms, see Infrmatinal Nte N. 2: Fr vercurrent prtectin f batteries, see (H). (3) Where fused discnnecting means are used, the line terminals f the discnnecting means shall be cnnected tward the energy strage system terminals NEC Significant Cde Changes Part 5 8

11 (4) Discnnecting means shall be permitted t be installed in energy strage system enclsures where explsive atmspheres can exist if listed fr hazardus lcatins. (5) Where the discnnecting means in (1) is nt within sight f the discnnecting means in (2), placards r directries shall be installed at the lcatins f all discnnecting means indicating the lcatin f all ther discnnecting means Cnnectin t Other Energy Surces. Cnnectin t ther energy surces shall cmply with the requirements f (A) Lad Discnnect. A lad discnnect that has multiple surces f pwer shall discnnect all energy surces when in the ff psitin. (B) Identified Interactive Equipment. Only inverters and ac mdules listed and identified as interactive shall be permitted n interactive systems. (C) Lss f Interactive System Pwer. Upn lss f primary surce, an ESS with a utility interactive inverter shall cmply with the requirements f (D) Unbalanced Intercnnectins. Unbalanced cnnectins between an energy strage system and electric pwer prductin surces shall be in accrdance with (E) Pint f Cnnectin. The pint f cnnectin between an energy strage system and electric pwer prductin surces shall be in accrdance with Energy Strage System Lcatins. Battery lcatins shall cnfrm t (A), (B), and (C). (A) Ventilatin. Prvisins apprpriate t the energy strage technlgy shall be made fr sufficient diffusin and ventilatin f any pssible gases frm the strage device, if present, t prevent the accumulatin f an explsive mixture. A pre-engineered r selfcntained ESS shall be permitted t prvide ventilatin in accrdance with the manufacturer s recmmendatins and listing fr the system. Infrmatinal Nte N. 1: See NFPA , Fire Cde, Chapter 52, fr ventilatin cnsideratins fr specific battery chemistries. Infrmatinal Nte N. 2: Sme strage technlgies d nt require ventilatin. Infrmatinal Nte N. 3: A surce fr design f ventilatin f battery systems is IEEE /ASHRAE Guideline Guide fr the Ventilatin and Thermal Management f Batteries fr Statinary Applicatins, and the UBC. Infrmatinal Nte N. 4: Fire prtectin cnsideratins are addressed in NFPA , Fire Cde. (B) Guarding f Live Parts. Guarding f live parts shall cmply with (C) Spaces Abut ESS Cmpnents. Spaces abut the ESS shall cmply with Wrking space shall be measured frm the edge f the ESS mdules, battery cabinets, racks, r trays. Fr battery racks, there shall be a minimum clearance f 25 mm (1 in.) between a cell cntainer and any wall r structure n the side nt requiring access fr maintenance. ESS mdules, battery cabinets, racks, r trays shall be permitted t cntact adjacent walls r structures, prvided that the battery shelf has a free air space fr nt less than 90 percent f its length. Pre-engineered and self-cntained ESSs shall be permitted t have wrking space between cmpnents within the system in accrdance with the manufacturer s recmmendatins and listing f the system. Infrmatinal Nte: Additinal space is ften needed t accmmdate ESS equipment histing equipment, tray remval, r spill cntainment. (D) Egress. A persnnel dr(s) intended fr entrance t and egress frm rms designated as ESS rms shall pen in the directin f egress and shall be equipped with listed panic hardware NEC Significant Cde Changes Part 5 9

12 (E) Illuminatin. Illuminatin shall be prvided fr wrking spaces assciated with ESS and their equipment and cmpnents. Luminaires shall nt be cntrlled by autmatic means nly. Additinal luminaires shall nt be required where the wrk space is illuminated by an adjacent light surce. The lcatin f luminaires shall nt d either f the fllwing: (1) Expse persnnel t energized system cmpnents while perfrming maintenance n the luminaires in the system space (2) Create a hazard t the system r system cmpnents upn failure f the luminaire Directry. ESS shall be indicated by (A) and (B). The markings r labels shall be in accrdance with (B). (A) Directry. A permanent plaque r directry denting all electric pwer surces n r in the premises shall be installed at each service equipment lcatin and at lcatins f all electric pwer prductin surces capable f being intercnnected. Exceptin: Installatins with large numbers f pwer prductin surces shall be permitted t be designated by grups. (B) Facilities with Stand-Alne Systems. Any structure r building with an ESS that is nt cnnected t a utility service surce and is a stand-alne system shall have a permanent plaque r directry installed n the exterir f the building r structure at a readily visible lcatin acceptable t the authrity having jurisdictin. The plaque r directry shall indicate the lcatin f system discnnecting means and that the structure cntains a stand-alne electrical pwer system. PART II. CIRCUIT REQUIREMENTS Circuit Sizing and Current. (A) Maximum Rated Current fr a Specific Circuit. The maximum current fr the specific circuit shall be calculated in accrdance with (A)(1) thrugh (A)(5). (1) Nameplate-Rated Circuit Current. The nameplate(s)- rated circuit current shall be the rated current indicated n the ESS nameplate(s) r system listing fr pre-engineered r self cntained systems f matched cmpnents intended fr field assembly as a system. (2) Inverter Output Circuit Current. The maximum current shall be the inverter cntinuus utput current rating. (3) Inverter Input Circuit Current. The maximum current shall be the cntinuus inverter input current rating when the inverter is prducing rated pwer at the lwest input vltage. (4) Inverter Utilizatin Output Circuit Current. The maximum current shall be the cntinuus inverter utput current rating when the inverter is prducing rated pwer at the lwest input vltage. (5) DC t DC Cnverter Output Current. The maximum current shall be the dc-t-dc cnverter cntinuus utput current rating. (B) Cnductr Ampacity and Overcurrent Device Ratings. The ampacity f the feeder circuit cnductrs frm the ESS(s) t the wiring system serving the lads t be serviced by the system shall nt be less than the greater f the (1) nameplate(s) rated circuit current as determined in accrdance with (A) r (2) the rating f the ESS(s) vercurrent prtective device(s). (C) Ampacity f Grunded r Neutral Cnductr. If the utput f a single-phase, 2- wire ESS utput(s) is cnnected t the grunded r neutral cnductr and a single ungrunded cnductr f a 3-wire system r f a 3-phase, 4-wire, wye cnnected system, the maximum unbalanced neutral lad current plus the ESS(s) utput rating shall nt exceed the ampacity f the grunded r neutral cnductr Overcurrent Prtectin. (A) Circuits and Equipment. ESS circuit cnductrs shall be prtected in accrdance with the requirements f Article 240. Prtectin devices fr ESS circuits shall be in accrdance with the requirements f (B) thrugh (F) NEC Significant Cde Changes Part 5 10

13 Circuits shall be prtected at the surce frm vercurrent. (B) Overcurrent Device Ampere Ratings. Overcurrent prtective devices, where required, shall be rated in accrdance with Article 240 and the rating prvided n systems serving the ESS and shall be nt less than 125 percent f the maximum currents calculated in (A). (C) Direct Current Rating. Overcurrent prtective devices, either fuses r circuit breakers, used in any dc prtin f an ESS shall be listed and fr dc and shall have the apprpriate vltage, current, and interrupting ratings fr the applicatin. (D) Current Limiting. A listed and labeled current-limiting vercurrent prtective device shall be installed adjacent t the ESS fr each dc utput circuit. Exceptin: Where current-limiting vercurrent prtectin is prvided fr the dc utput circuits f a listed ESS, additinal current-limiting vercurrent devices shall nt be required. (E) Fuses. Means shall be prvided t discnnect any fuses assciated with ESS equipment and cmpnents when the fuse is energized frm bth directins and is accessible t ther than qualified persns. Switches, pulluts, r similar devices that are rated fr the applicatin shall be permitted t serve as a means t discnnect fuses frm all surces f supply. (F) Lcatin. Where ESS input and utput terminals are mre than 1.5 m (5 ft) frm cnnected equipment, r where the circuits frm these terminals pass thrugh a wall r partitin, vercurrent prtectin shall be prvided at the ESS Charge Cntrl. (A) General. Prvisins shall be prvided t cntrl the charging prcess f the ESS. All adjustable means fr cntrl f the charging prcess shall be accessible nly t qualified persns. Infrmatinal Nte: Certain types f energy strage equipment such as valve-regulated lead acid r nickel cadmium can experience thermal failure when vercharged. (B) Diversin Charge Cntrller. (1) Sle Means f Regulating Charging. An ESS emplying a diversin charge cntrller as the sle means f regulating charging shall be equipped with a secnd independent means t prevent vercharging f the strage device. (2) Circuits with Diversin Charge Cntrller and Diversin Lad. Circuits cntaining a diversin charge cntrller and a diversin lad shall cmply with the fllwing: (1) The current rating f the diversin lad shall be less than r equal t the current rating f the diversin lad charge cntrller. The vltage rating f the diversin lad shall be greater than the maximum ESS vltage. The pwer rating f the diversin lad shall be at least 150 percent f the pwer rating f the charging surce. (2) The cnductr ampacity and the rating f the vercurrent device fr this circuit shall be at least 150 percent f the maximum current rating f the diversin charge cntrller. (3) Energy Strage Systems Using Utility- Interactive Inverters. Systems using utilityinteractive inverters t cntrl energy strage state-f-charge by diverting excess pwer int the utility system shall cmply with (B)(3)(a) and (B)(3)(b). (a) These systems shall nt be required t cmply with (B)(2). (b) These systems shall have a secnd, independent means f cntrlling the ESS charging prcess fr use when the utility is nt present r when the primary charge cntrller fails r is disabled. (C) Charge Cntrllers and DC-t-DC Cnverters. Where charge cntrllers and ther DC-t-DC pwer cnverters that increase r decrease the utput current r utput vltage with respect t the input current r input 2017 NEC Significant Cde Changes Part 5 11

14 vltage are installed, all f the fllwing shall apply: (1) The ampacity f the cnductrs in utput circuits shall be based n the maximum rated cntinuus utput current f the charge cntrller r cnverter fr the selected utput vltage range. (2) The vltage rating f the utput circuits shall be based n the maximum vltage utput f the charge cntrller r cnverter fr the selected utput vltage range. PART III. ELECTROCHEMICAL ENERGY STORAGE SYSTEMS Part III f this article applies t ESSs that are cmprised f sealed and nn-sealed cells r batteries r system mdules that are cmprised f multiple sealed cells r batteries that are nt cmpnents within a listed prduct. Infrmatinal Nte: An energy strage cmpnent, such as batteries, that are integrated int a larger piece f listed equipment, such as an uninterruptible pwer supply (UPS), are examples f cmpnents within a listed prduct Installatin f Batteries. (A) Dwelling Units. An ESS fr dwelling units shall nt exceed 100 vlts between cnductrs r t grund. Exceptin: Where live parts are nt accessible during rutine ESS maintenance, an ESS vltage exceeding 100 vlts shall be permitted. (B) Discnnectin f Series Battery Circuits. Battery circuits subject t field servicing, where exceeding 240 vlts nminal between cnductrs r t grund, shall have prvisins t discnnect the series-cnnected strings int segments nt exceeding 240 vlts nminal fr maintenance by qualified persns. Nn lad-break blted r plug-in discnnects shall be permitted. (C) Strage System Maintenance Discnnecting Means. ESS exceeding 100 vlts between cnductrs r t grund shall have a discnnecting means, accessible nly t qualified persns, that discnnects ungrunded and grunded circuit cnductr(s) in the electrical strage system fr maintenance. This discnnecting means shall nt discnnect the grunded circuit cnductr(s) fr the remainder f any ther electrical system. A nn ladbreak-rated switch shall be permitted t be used as a discnnecting means. (D) Strage Systems f Mre Than 100 Vlts. On ESS exceeding 100 vlts between the cnductrs r t grund, the battery circuits shall be permitted t perate with ungrunded cnductrs, prvided a grund-fault detectr and indicatr is installed t mnitr fr grund faults within the strage system Battery and Cell Terminatins. (A) Crrsin Preventin. Antixidant material suitable fr the battery cnnectin shall be used when recmmended by the battery r cell manufacturer. Infrmatinal Nte: The battery manufacturer s installatin and instructin manual can be used fr guidance fr acceptable materials. (B) Intercell and Intertier Cnductrs and Cnnectins. The ampacity f fieldassembled intercell and intertier cnnectrs and cnductrs shall be f such crss-sectinal area that the temperature rise under maximum lad cnditins and at maximum ambient temperature shall nt exceed the safe perating temperature f the cnductr insulatin r f the material f the cnductr supprts. Infrmatinal Nte: Cnductrs sized t prevent a vltage drp exceeding 3 percent f maximum anticipated lad, and where the maximum ttal vltage drp t the furthest pint f cnnectin des nt exceed 5 percent, may nt be apprpriate fr all battery applicatins. IEEE , Guide fr the Prtectin f Statinary Battery Systems, prvides guidance fr vercurrent prtectin and assciated cable sizing. (C) Battery Terminals. Electrical cnnectins t the battery and the cable(s) 2017 NEC Significant Cde Changes Part 5 12

15 between cells n separate levels r racks shall nt put mechanical strain n the battery terminals. Terminal plates shall be used where practicable Battery Intercnnectins. Flexible cables, as identified in Article 400, in sizes 2/0 AWG and larger shall be permitted within the battery enclsure frm battery terminals t a nearby junctin bx where they shall be cnnected t an apprved wiring methd. Flexible battery cables shall als be permitted between batteries and cells within the battery enclsure. Such cables shall be listed and identified as misture resistant. Flexible, fine-stranded cables shall nly be used with terminals, lugs, devices, r cnnectrs in accrdance with Accessibility. The terminals f all cells r multicell units shall be readily accessible fr readings, inspectin, and cleaning where required by the equipment design. One side f transparent battery cntainers shall be readily accessible fr inspectin f the internal cmpnents Battery Lcatins. Battery lcatins shall cnfrm t (A), (B), and (C). (A) Live Parts. Guarding f live parts shall cmply with (B) Tp Terminal Batteries. Where tp terminal batteries are installed n tiered racks r n shelves f battery cabinets, wrking space in accrdance with the strage equipment manufacturer s instructins shall be prvided between the highest pint n a strage system cmpnent and the rw, shelf, r ceiling abve that pint. Infrmatinal Nte: IEEE 1187 prvides guidance fr tp clearance f VRLA batteries, which are the mst cmmnly used battery in cabinets. (C) Gas Piping. Gas piping shall nt be permitted in dedicated battery rms. PART IV. FLOW BATTERY ENERGY STORAGE SYSTEMS Part IV applies t ESSs cmpsed f r cntaining flw batteries General. All electrical cnnectins t and frm the system and system cmpnents shall be in accrdance with the applicable prvisins f Article 692. The system and system cmpnents shall als meet the prvisins f Parts I and II f this article. Unless therwise directed by this article, flw battery ESS shall cmply with the applicable prvisins f Article Electrlyte Classificatin. The electrlyte(s) that are acceptable fr use in the batteries assciated with the ESS shall be identified by name and chemical cmpsitin. Such identificatin shall be prvided by readily discernable signage adjacent t every lcatin in the system where the electrlyte can be put int r taken ut f the system Electrlyte Cntainment. Flw battery systems shall be prvided with a means fr electrlyte cntainment t prevent spills f electrlyte frm the system. An alarm system shall be prvided t signal an electrlyte leak frm the system. Electrical wiring and cnnectins shall be lcated and ruted in a manner that mitigates the ptential fr expsure t electrlytes Flw Cntrls. Cntrls shall be prvided t safely shut dwn the system in the event f electrlyte blckage Pumps and Other Fluid Handling Equipment. Pumps and ther fluid handling equipment are t be rated/specified suitable fr expsure t the electrlytes NEC Significant Cde Changes Part 5 13

16 PART V. OTHER ENERGY STORAGE TECHNOLOGIES The prvisins f Part V apply t ESSs using ther technlgies intended t stre energy and when there is a demand fr electrical pwer t use the stred energy t generate the needed pwer General. All electrical cnnectins t and frm the system and system cmpnents shall be in accrdance with the applicable prvisins f this Cde. Unless therwise directed by this article, ther energy strage technlgies shall cmply with the applicable prvisins f Part III f Article 705. Reasn fr the Change A new Article 706 titled, Energy Strage Systems, was added t the NEC pertaining t all permanently installed energy strage systems (ESS). ARTICLE 708 Critical Operatins Pwer Systems (COPS) (A)(2) Receptacle Identificatin Feeder and Branch Circuit Wiring. [Critical Operatins Pwer Systems (COPS)] (A) Identificatin. (1) Bxes and Enclsures. In a building r at a structure where a critical peratins pwer system and any ther type f pwer system are present, all bxes and enclsures (including transfer switches, generatrs, and pwer panels) fr critical peratins pwer system circuits shall be permanently marked s they will be readily identified as a cmpnent f the critical peratins pwer system. (2) Receptacle Identificatin. In a building in which COPS are present with ther types f pwer systems described in ther sectins in this article, the cver plates fr the receptacles r the receptacles themselves supplied frm the COPS shall have a distinctive clr r marking s as t be readily identifiable. Nnlcking-type, 125-vlt, 15- and 20-ampere receptacles supplied frm the COPS shall have an illuminated face r an indicatr light t indicate that there is pwer t the receptacle. Exceptin: If the COPS supplies pwer t a DCOA that is a stand-alne building, receptacle cver plates r the receptacles themselves shall nt be required t have distinctive marking. Reasn fr the Change In additin t the distinctive clr r marking requirement fr COPS receptacles, all nnlcking-type, 125-vlt, 15- and 20- ampere receptacles supplied frm the COPS are nw required t have an illuminated face r an indicatr light t indicate that there is pwer t the receptacle. ARTICLE 710 Stand-Alne Systems Article 710 Stand-Alne Systems The fllwing is the new Article 710 titled, Stand-Alne Systems, which put all standalne system requirements in ne lcatin Scpe. This article cvers electric pwer prductin surces perating in stand-alne mde Equipment Apprval. All equipment shall be listed and labeled r field labeled fr the intended use General. Premises wiring systems shall be adequate t meet the requirements f this Cde fr similar installatins supplied by a feeder r service. The wiring n the supply side f the building r structure discnnecting means shall cmply with the requirements f this Cde, except as mdified by (A) thrugh (F) NEC Significant Cde Changes Part 5 14

17 (A) Supply Output. Pwer supply t premises wiring systems shall be permitted t have less capacity than the calculated lad. The capacity f the stand-alne supply shall be equal t r greater than the lad psed by the largest single utilizatin equipment cnnected t the system. Calculated general lighting lads shall nt be cnsidered as a single lad. (B) Sizing and Prtectin. The circuit cnductrs between a stand-alne surce and a building r structure discnnecting means shall be sized based n the sum f the utput ratings f the stand-alne surces. (C) Single 120-Vlt Supply. Stand-alne systems shall be permitted t supply 120 vlts t single-phase, 3-wire, 120/240-vlt service equipment r distributin panels where there are n 240-vlt utlets and where there are n multiwire branch circuits. In all installatins, the sum f the ratings f the pwer surces shall be less than the rating f the neutral bus in the service equipment. This equipment shall be marked with the fllwing wrds r equivalent: WARNING: SINGLE 120-VOLT SUPPLY. DO NOT CONNECT MULTIWIRE BRANCH CIRCUITS! (D) Energy Strage r Backup Pwer System Requirements. Energy strage r backup pwer supplies are nt required. (E) Back-Fed Circuit Breakers. Plug-in type back-fed circuit breakers cnnected t an intercnnected supply shall be secured in accrdance with (D). Circuit breakers marked line and lad shall nt be back-fed. (F) Vltage and Frequency Cntrl. The stand-alne supply shall be cntrlled s that vltage and frequency remain within suitable limits fr the cnnected lads. Reasn fr the Change The requirements f stand-alne systems were brught t ne lcatin and a new Article 710, Stand-Alne Systems, was created fr the 2017 NEC. ARTICLE 712 Direct Current Micrgrids Article 712 Direct Current Micrgrids The fllwing is the new Article 712 titled, Direct Current Micrgrids, which was added fr a pwer distributin system cnsisting f mre than ne intercnnected dc pwer surces, supplying dc dc cnverters(s), dc lads(s), and/r ac lads(s) pwered by dc ac inverters(s). PART I. GENERAL Scpe. This article applies t direct current micrgrids Definitins. Direct Current Micrgrid (DC Micrgrid). A direct current micrgrid is a pwer distributin system cnsisting f mre than ne intercnnected dc pwer surce, supplying dc-dc cnverter (s), dc lad (s), and/r ac lad (s) pwered by dc-ac inverter (s). A dc micrgrid is typically nt directly cnnected t an ac primary surce f electricity, but sme dc micrgrids intercnnect via ne r mre dc-ac bidirectinal cnverters r dc ac inverters. Infrmatinal Nte: Direct current pwer surces include ac-dc cnverters (rectifiers), bidirectinal dc-ac inverters/cnverters, phtvltaic systems, wind generatrs, energy strage systems (including batteries), and fuel cells. Grunded Tw-Wire DC System. A system that has a slid cnnectin r referencegrund between ne f the current carrying cnductrs and the equipment grunding system NEC Significant Cde Changes Part 5 15

18 Grunded Three-Wire DC System. A system with a slid cnnectin r referencegrund between the center pint f a biplar dc pwer surce and the equipment grunding system. Nminal Vltage. A value assigned t a circuit r system fr the purpse f cnveniently designating its dc vltage class. Infrmatinal Nte: The actual vltage at which a circuit perates can vary frm the nminal vltage within a range that permits satisfactry peratin f equipment. Reference-Grunded DC System. A system that is nt slidly grunded but has a lw- resistance electrical reference that maintains vltage t grund in nrmal peratin. Resistively Grunded. A system with a high- resistance cnnectin between the current carrying cnductrs and the equipment grunding system. Primary DC Surce. A surce that supplies the majrity f the dc lad in a dc micrgrid. Ungrunded DC System. A system that has n direct r resistive cnnectin between the current carrying cnductrs and the equipment grunding system Other Articles. Wherever the requirements f ther articles f this Cde and Article 712 differ, the requirements f Article 712 shall apply. DC micrgrids intercnnected thrugh an inverter r bi-directinal cnverter with ac electric pwer prductin surces shall cmply with Article Listing and Labeling. Any equipment used in the dc circuits f a direct-current micr grid shall be listed and labeled fr dc use Directry. A permanent directry denting all dc electric pwer surces perating t supply the dc micrgrid shall be installed at each surce lcatin capable f acting as the primary dc surce. PART II. CIRCUIT REQUIREMENTS Identificatin f Circuit Cnductrs (A) Ungrunded circuit cnductrs in dc micrgrids shall be identified accrding t the requirements f 210.5(C)(2) fr branch circuits and (C)(2) fr feeders. (B) Ungrunded cnductrs f 6 AWG r smaller shall be permitted t be identified by plarity at all terminatin, cnnectin, and splice pints by marking tape, tagging, r ther apprved means System Vltage. The system vltage f a dc micrgrid shall be determined by ne f the fllwing methds: (1) The nminal vltage t grund fr slidly grunded systems (2) The nminal vltage t grund fr referencegrunded systems (3) The highest nminal vltage between cnductrs fr resistively grunded dc systems and ungrunded dc systems. Infrmatinal Nte: Examples f nminal dc system vltages include but are nt limited t 24, 48, 125, 190/380, r 380 vlts. PART III. DISCONNECTING MEANS DC Surce Discnnecting Means. The utput f each dc surce shall have a readily accessible, discnnecting means that is lckable in the pen psitin and adjacent t the surce Discnnectin f Ungrunded Cnductrs. In slidly grunded tw- and three-wire systems, the discnnecting means shall simultaneusly pen all ungrunded 2017 NEC Significant Cde Changes Part 5 16

19 cnductrs. In ungrunded, resistively grunded and reference-grunded systems, such devices shall pen all current-carrying cnductrs Directinal Current Devices. Discnnecting means shall be listed, be marked fr use in a single current directin, and nly be used in the designated current directin. Infrmatinal Nte: Examples f directinal current devices are magnetically quenched cntactrs and semicnductr switches in vercurrent devices. PART IV. WIRING METHODS System Grunding. (A) General. Direct-current micrgrids shall be grunded in accrdance with (B) Over 300 Vlts. DC micrgrids perating at vltages greater than 300 vlts dc shall be reference-grunded dc systems r resistively grunded dc systems Grund Fault Detectin Equipment. Ungrunded, reference grunded, r resistively grunded dc micrgrids perating at greater than 60 vlts dc shall have grund fault detectin that indicates that a fault has ccurred. The grund fault equipment shall be marked in accrdance with (C) Arc Fault Prtectin. Where required elsewhere in this Cde, specific systems within the DC micrgrid shall have arc fault prtectin. The arc fault prtectin equipment shall be listed. Infrmatinal Nte: Sectin 90.4 applies when suitable equipment fr arc fault prtectin is nt available. PART V. MARKING Distributin Equipment and Cnductrs. Distributin equipment and cnductrs shall be marked as required elsewhere in this Cde Available DC Shrt-Circuit Current. (A) Field Marking. The maximum available dc shrt-circuit current n the dc micrgrid shall be field marked at the dc surce (s). The field marking(s) shall include the date the shrtcircuit current calculatin was perfrmed and be f sufficient durability t withstand the envirnment invlved. (B) Mdificatins. When mdificatins t the electrical installatin ccur that affect the maximum available shrt-circuit current at the dc surce, the maximum available shrt-circuit current shall be verified r recalculated as necessary t ensure the equipment ratings are sufficient fr the maximum available shrtcircuit current at the line terminals f the equipment. The required field marking(s) in (A) shall indicate the new maximum available shrt-circuit current and date. PART VI. PROTECTION Overcurrent Prtectin. Equipment and cnductrs cnnected t mre than ne electrical surce shall have vercurrent prtective devices t prvide prtectin frm all surces Interrupting and Shrt-Circuit Current Ratings. Cnsideratin shall be given t the cntributin f shrt-circuit currents frm all intercnnected pwer surces fr the interrupting ratings and shrtcircuit current ratings f equipment in the dc micrgrid system (s). Overcurrent prtective devices and equipment used within a dc micrgrid shall have an interrupting rating at nminal circuit vltage r a shrt-circuit current rating sufficient fr the available shrtcircuit current at the line terminals f the equipment NEC Significant Cde Changes Part 5 17

20 PART VII. SYSTEMS OVER 1000 VOLTS General. Systems with a maximum vltage between cnductrs f ver 1000 vlts dc shall cmply with Article 490 and ther requirements in this Cde applicable t installatins rated ver 1000 vlts. Reasn fr the Change A new Article 712 fr dc micrgrids was added fr a pwer distributin system cnsisting f mre than ne intercnnected dc pwer surces, supplying dc dc cnverters(s), dc lads(s), and/r ac lads(s) pwered by dc ac inverters(s). ARTICLE 725 Class 1, Class 2, and Class 3 Remte- Cntrl, Signaling, and Pwer- Limited Circuits 725.3(M) and (N) Other Articles (Class 1, Class 2, and Class 3 Remte- Cntrl, Signaling, and Pwer- Limited Circuits) Other Articles (Class 1, Class 2, and Class 3 Remte-Cntrl, Signaling, and Pwer-Limited Circuits) Circuits and equipment shall cmply with the articles r sectins listed in 725.3(A) thrugh (L) (N). Only thse sectins f Article 300 referenced in this article shall apply t Class 1, Class 2, and Class 3 circuits. (M) Cable Ruting Assemblies. Class 2, Class 3 and Type PLTC cables shall be permitted t be installed in plenum cable ruting assemblies, riser cable ruting assemblies, and general-purpse cable ruting assemblies selected in accrdance with the prvisins f Table (c), listed in accrdance with the prvisins f , and installed in accrdance with the prvisins f (C) and (N) Cmmunicatins Raceways. Class 2, Class 3 and Type PLTC cables shall be permitted t be installed in plenum cmmunicatins raceways, riser cmmunicatins raceways and general-purpse cmmunicatins raceways selected in accrdance with the prvisins f Table (b), listed in accrdance with the prvisins f , and installed in accrdance with the prvisins f and thrugh , where the requirements applicable t electrical nnmetallic tubing (ENT) apply. Reasn fr the Change New 725.3(M) and (N) were added fr Other Articles t prvide guidance in the selectin, listing and installatin requirements fr cable ruting assemblies and cmmunicatin raceways used fr Class 2, Class 3 and PLTC cables (K)(6), (L)(6) and (M)(6) Installatin f Class 2, Class 3, and PLTC Cables Installatin f Class 2, Class 3, and PLTC Cables. Installatin f Class 2, Class 3, and PLTC cables shall cmply with (A) thrugh (M). (K) Other Building Lcatins. The fllwing wires and cables shall be permitted t be installed in building lcatins ther than the lcatins cvered in (B) thrugh (I): (See NEC text at (K)(1) thrugh (6) fr cmplete list f wiring methds) (6) Type CMUC undercarpet cmmunicatins wires and cables installed under carpet, mdular flring, and planks (L) Multifamily Dwellings. The fllwing wires and cables shall be permitted t be installed in multifamily dwellings in lcatins ther than the lcatins cvered in (B) thrugh (I): (See NEC text at (L)(1) thrugh (6) fr cmplete list f wiring methds) 2017 NEC Significant Cde Changes Part 5 18

21 (6) Type CMUC undercarpet cmmunicatins wires and cables installed under carpet, mdular flring, and planks (M) One- and Tw-Family Dwellings. The fllwing wires and cables shall be permitted t be installed in ne- and tw-family dwellings in lcatins ther than the lcatins cvered in (B) thrugh (I): (See NEC text at (M)(1) thrugh (6) fr cmplete list f wiring methds) (6) Type CMUC undercarpet cmmunicatins wires and cables installed under carpet, mdular flring, and planks Reasn fr the Change New Cde language was intrduced at (K), (L), and (M) t clearly indicate that Type CMUC undercarpet cmmunicatins wires and cables can be installed under mdular flring and planks, as well as under carpet , Table Transmissin f Pwer and Data. (Class 1, Class 2, and Class 3 Remte-Cntrl, Signaling, and Pwer-Limited Circuits) Transmissin f Pwer and Data. (Class 1, Class 2, and Class 3 Remte-Cntrl, Signaling, and Pwer-Limited Circuits) The requirements f (A) and (B) shall apply t Class 2 and Class 3 circuits that transmit pwer and data t a pwered device. The requirements f Parts I and III f Article 725 and shall apply t Class 2 and Class 3 circuits that transmit pwer and data. The cnductrs that carry pwer fr the data circuits shall be cpper. The current in the pwer circuit shall nt exceed the current limitatin f the cnnectrs. Infrmatinal N. 1: One example f the use f cables that transmit pwer and data is the cnnectin f clsed-circuit TV cameras (CCTV). Infrmatinal Nte N. 2: The 8P8C cnnectr is in widespread use with pwered cmmunicatins systems. These cnnectrs are typically rated at 1.3 amperes maximum. Table Ampacities f Each Cnductr in Amperes in 4-Pair Class 2 r Class 3 Data Cables Based n Cpper Cnductrs at an Ambient Temperature f 30 C (86 F) with All Cnductrs in All Cables Carrying Current, 60 C (140 F), 75 C (167 F), and 90 C (194 F) Rated Cables (See NEC and illustratin prvided fr cmplete text f Table ) (A) Use f Class 2 r Class 3 Cables t Transmit Pwer and Data. Where Types CL3P, CL2P, CL3R, CL2R, CL3, r CL2 transmit pwer and data, the fllwing shall apply, as applicable: (1) The ampacity ratings in Table shall apply at an ambient temperature f 30 C (86 F). (2) Fr ambient temperatures abve 30 C (86 F), the crrectin factrs f (B)(2) shall apply. Infrmatinal Nte: One example f the use f Class 2 cables is a netwrk f clsed- circuit TV cameras using 24 AWG, 60 C rated, Type CL2R, Categry 5e lcal area netwrk (LAN) cables. (B) Use f Class 2-LP r Class 3-LP Cables t Transmit Pwer and Data. Types CL3P-LP, CL2P-LP, CL3R-LP, CL2R-LP, CL3-LP, r CL2-LP shall be permitted t supply pwer t equipment at a current level up t the marked ampere limit lcated immediately fllwing the suffix LP and shall be permitted t transmit data t the equipment. The Class 2-LP and Class 3-LP cables shall cmply with the fllwing, as applicable: Infrmatinal Nte 1: The (xxa) fllwing the suffix -LP indicates the ampacity f each cnductr in a cable NEC Significant Cde Changes Part 5 19

22 Infrmatinal Nte 2: An example f a limited pwer (LP) cable is a cable marked Type CL2- LP(0.5A), 23 AWG. A Type CL2-LP (0.5), 23 AWG culd be used in any lcatin where a Type CL2 culd be used; hwever, the LP cable wuld be suitable fr carrying up t 0.5 A per cnductr, regardless f the number f cables in a bundle. If used in a 7-cable bundle, the same cable culd carry up t 1.2 amperes per cnductr. (1) Cables with the suffix -LP shall be permitted t be installed in bundles, raceways, cable trays, cmmunicatins raceways, and cable ruting assemblies. (2) Cables with the suffix -LP and a marked ampere level shall fllw the substitutin hierarchy f Table and Figure (A) fr the cable type withut the suffix LP and withut the marked ampere level. (3) System design shall be permitted by qualified persns under engineering supervisin. Reasn fr the Change New prvisins were added at and Table pertaining t remte pwering ver lcal area netwrking (LAN) cable. Additinal infrmatin was intrduced cncerning new Type LP cable. ARTICLE 727 Instrumentatin Type Cable: Type ITC 727.4(5) Ex. t (5) Uses Permitted. (Instrumentatin Tray Cable: Type ITC) Uses Permitted. (Instrumentatin Tray Cable: Type ITC) Type ITC cable shall be permitted t be used as fllws in industrial establishments where the cnditins f maintenance and supervisin ensure that nly qualified persns service the installatin: (1) In cable trays. (2) In raceways. (3) In hazardus lcatins as permitted in , , , , , , and (4) Enclsed in a smth metallic sheath, cntinuus crrugated metallic sheath, r interlcking tape armr applied ver the nnmetallic sheath in accrdance with The cable shall be supprted and secured at intervals nt exceeding 1.8 m (6 ft). (5) Cable, withut a metallic sheath r armr, that cmplies with the crush and impact requirements f Type MC cable and is identified fr such use with the marking ITC-ER shall be permitted t be installed expsed. The cable shall be cntinuusly supprted and prtected against physical damage using mechanical prtectin such as dedicated struts, angles, r channels. The cable shall be secured at intervals nt exceeding 1.8 m (6 ft). Exceptin: Where nt subject t physical damage, Type ITC-ER shall be permitted t transitin between cable trays and between cable trays and utilizatin equipment r devices fr a distance nt t exceed 1.8 m (6 ft) withut cntinuus supprt. The cable shall be mechanically supprted where exiting the cable tray t ensure that the minimum bending radius is nt exceeded. (6) As aerial cable n a messenger. (7) Direct buried where identified fr the use. (8) Under raised flrs in rms cntaining industrial prcess cntrl equipment and rack rms where arranged t prevent damage t the cable. (9) Under raised flrs in infrmatin technlgy equipment rms in accrdance with 645.5(E)(5)(b). Reasn fr the Change The same exceptin that exists fr pwer and cntrl tray cable (Type TC-ER) at (7) has been added at 727.4(5) fr instrumentatin tray cable (Type ITC-ER). ARTICLE 760 Fire Alarm Systems 2017 NEC Significant Cde Changes Part 5 20

23 (G) and (I) Listing and Marking f NPLFA Cables and Listing and Marking f PLFA Cables and Insulated Cntinuus Line-Type Fire Detectrs Part IV. Listing Requirements (Fire Alarm Systems) Listing and Marking f NPLFA Cables. Nn-pwer-limited fire alarm cables installed as wiring within buildings shall be listed in accrdance with (A) and (B) and as being resistant t the spread f fire in accrdance with (C) thrugh (F), and shall be marked in accrdance with (G). Cable used in a wet lcatin shall be listed fr use in wet lcatins r have a misture-impervius metal sheath. (G) NPLFA Cable Markings. Multicnductr nn-pwerlimited fire alarm cables shall be marked in accrdance with Table (G). Nn pwerlimited fire alarm circuit cables shall be permitted t be marked with a maximum usage vltage rating f 150 vlts. Cables that are listed fr circuit integrity shall be identified with the suffix CI as defined in (F). Temperature rating shall be marked n the jacket f NPLFA cables that have a temperature rating exceeding 60 C (140 F). The jacket f NPLFA cables shall be marked with the cnductr size. Infrmatinal Nte: Cable types are listed in descending rder f fire resistance rating Listing and Marking f PLFA Cables and Insulated Cntinuus Line-Type Fire Detectrs. PLFA cables installed as wiring within buildings shall be listed as being resistant t the spread f fire and ther criteria in accrdance with (A) thrugh (H) and shall be marked in accrdance with (I). Insulated cntinuus line-type fire detectrs shall be listed in accrdance with (J). Cable used in a wet lcatin shall be listed fr use in wet lcatins r have a misture-impervius metal sheath. (I) Cable Marking. The cable shall be marked in accrdance with Table (I). The vltage rating shall nt be marked n the cable. Cables that are listed fr circuit integrity shall be identified with the suffix CI as defined in (G). Temperature rating shall be marked n the jacket f PLFA cables that have a temperature rating exceeding 60 C (140 F). The jacket f PLFA cables shall be marked with the cnductr size. Infrmatinal Nte: Vltage ratings n cables may be misinterpreted t suggest that the cables may be suitable fr Class 1, electric light, and pwer applicatins. Exceptin: Vltage markings shall be permitted where the cable has multiple listings and vltage marking is required fr ne r mre f the listings. Reasn fr the Change New temperature rating marking requirements were added fr fire alarm circuits requiring the jacket f NPLFA and PLFA cables that have a temperature rating exceeding 60 C (140 F) t be marked with the apprpriate temperature rating. The jacket f these fire alarm cables must als be marked with the cnductr size as well. ARTICLE 770 Optical Fiber Cables and Raceways Overhead (Aerial) Optical Fiber Cables Overhead (Aerial) Optical Fiber Cables. Overhead ptical fiber cables cntaining a nn current-carrying metallic member entering buildings shall cmply with (A) and (B). (A) On Ples and In-Span. Where utside plant ptical fiber cables and electric light r pwer cnductrs are supprted by the same ple r are run parallel t each ther in-span, the cnditins described in (A)(1) thrugh (A)(4) shall be met. (1) Relative Lcatin. Where practicable, the utside plant ptical fiber cables shall be 2017 NEC Significant Cde Changes Part 5 21

24 lcated belw the electric light r pwer cnductrs. (2) Attachment t Crss- Arms. Attachment f utside plant ptical fiber cables t a crss-arm that carries electric light r pwer cnductrs shall nt be permitted. (3) Climbing Space. The climbing space thrugh utside plant ptical fiber cables shall cmply with the requirements f (D). (4) Clearance. Supply service drps and sets f verhead service cnductrs f 0 t 750 vlts running abve and parallel t ptical fiber cable service drps shall have a minimum separatin f 300 mm (12 in.) at any pint in the span, including the pint f their attachment t the building. Clearance f nt less than 1.0 m (40 in.) shall be maintained between the tw services at the ple. (B) Abve Rfs. Outside plant ptical fiber cables shall have a vertical clearance f nt less than 2.5 m (8 ft) frm all pints f rfs abve which they pass. Exceptin N. 1: The requirement f (B) shall nt apply t auxiliary buildings such as garages and the like. Exceptin N. 2: A reductin in clearance abve nly the verhanging prtin f the rf t nt less than 450 mm (18 in.) shall be permitted if (a) nt mre than 1.2 m (4 ft) f ptical fiber cable service drp cable passes abve the rf verhang, and (b) the cable is terminated at a thrugh- r abve-the-rf raceway r apprved supprt. Exceptin N. 3: Where the rf has a slpe f nt less than 100 mm in 300 mm (4 in. in 12 in.), a reductin in clearance t nt less than 900 mm (3 ft) shall be permitted. Infrmatinal Nte: Fr additinal infrmatin regarding verhead wires and cables, see ANSI/IEEE C2-2012, Natinal Electric Safety Cde, Part 2, Safety Rules fr Overhead Lines. Reasn fr the Change A new was added under Part II f Article 770 titled, Overhead (Aerial) Optical Fiber Cables. This sectin cntains needed infrmatin fr the installatin f verhead (aerial) ptical fiber cables t buildings directly fr Article (A) and (B) Optical Fiber Cables Entering Building Unlisted Cables and Raceways Entering Buildings. (Optical Fiber Cables and Raceways) (A) Cnductive and Nncnductive Cables. Unlisted cnductive and nncnductive utside plant ptical fiber cables shall be permitted t be installed in building spaces, ther than risers, ducts used fr envirnmental air, plenums used fr envirnmental air, and ther spaces used fr envirnmental air, where the length f the cable within the building, measured frm its pint f entrance, des nt exceed 15 m (50 ft) and the cable enters the building frm the utside and is terminated in an enclsure. The pint f entrance shall be permitted t be extended frm the penetratin f the external wall r flr slab by cntinuusly enclsing the entrance ptical fiber cables in rigid metal cnduit (RMC) r intermediate metal cnduit (IMC) t the pint f emergence. Infrmatinal Nte N. 1: Splice cases r terminal bxes, bth metallic and plastic types, typically are used as enclsures fr splicing r terminating ptical fiber cables. Infrmatinal Nte N. 2: See fr the definitin f Pint f Entrance. (B) Nncnductive Cables in Raceway. Unlisted nncnductive utside plant ptical fiber cables shall be permitted t enter the building frm the utside and shall be permitted t be installed in any f the fllwing raceways: (1) Intermediate metal cnduit (IMC) (2) Rigid metal cnduit (RMC) (3) Rigid plyvinyl chlride cnduit (PVC) (4) Electrical metallic tubing (EMT) 2017 NEC Significant Cde Changes Part 5 22

25 Unlisted nncnductive utside plant cables installed in rigid plyvinyl chlride cnduit (PVC) r electrical metallic tubing (EMT) shall nt be permitted t be installed in risers, ducts used fr envirnmental air, plenums used fr envirnmental air, and ther spaces used fr envirnmental air. Reasn fr the Change The pint f entrance is nw permitted t be extended frm the penetratin f the external wall r flr slab by cntinuusly enclsing the entrance ptical fiber cables in RMC r IMC t the pint f emergence. Cde language was als added t clarify that unlisted nncnductive utside plant ptical fiber cables installed in PVC r EMT cannt be installed in risers, ducts used fr envirnmental air, plenums used fr envirnmental air, and ther spaces used fr envirnmental air Metallic Entrance Cnduit Grunding Cde Language: Metallic Entrance Cnduit Grunding. (Optical Fiber Cables and Raceways) Rigid metal cnduit (RMC) r intermediate metal cnduit (IMC) Metallic cnduit cntaining ptical fiber entrance cable shall be cnnected by a bnding cnductr r grunding electrde cnductr t a grunding electrde in accrdance with (B). Reasn fr the Change The reference t RMC and IMC was remved and replaced with metallic cnduit as all metallic cnduits cntaining ptical fiber entrance cables shuld require a bnding cnnectin t a grunding electrde (nt just RMC and IMC) (B)(3)(2) Lightning Prtectin Systems Cnductrs Entrance Cable Bnding and Grunding. (Optical Fiber Cables and Raceways) Where required, the nn current-carrying metallic members f ptical fiber cables entering buildings shall be bnded r grunded as specified in (A) thrugh (D). (B) Electrde. The bnding cnductr and grunding electrde cnductr shall be cnnected in accrdance with (B)(1), (B)(2), r (B)(3). (1) In Buildings r Structures with an Intersystem Bnding Terminatin. If the building r structure served has an intersystem bnding terminatin as required by , the bnding cnductr shall be cnnected t the intersystem bnding terminatin. Infrmatinal Nte: See Part I f Article 100 fr the definitin f Intersystem Bnding Terminatin. (2) In Buildings r Structures with Grunding Means. If an intersystem bnding terminatin is established, (A) shall apply. If the building r structure served has n intersystem bnding terminatin, the bnding cnductr r grunding electrde cnductr shall be cnnected t the nearest accessible lcatin n ne f the fllwing: (1) The building r structure grunding electrde system as cvered in (2) The grunded interir metal water piping system, within 1.5 m (5 ft) frm its pint f entrance t the building, as cvered in (3) The pwer service accessible means external t enclsures using the ptins identified in (A), Exceptin as cvered in (4) The nnflexible metallic pwer service raceway (5) The service equipment enclsure (6) The grunding electrde cnductr r the grunding electrde cnductr metal enclsure f the pwer service, r (7) The grunding electrde cnductr r the grunding electrde f a building r structure discnnecting means that is grunded t an electrde as cvered in (3) In Buildings r Structures Withut Intersystem Bnding Terminatin r 2017 NEC Significant Cde Changes Part 5 23

26 Grunding Means. If the building r structure served has n intersystem bnding terminatin r grunding means, as described in (B)(2), the grunding electrde cnductr shall be cnnected t either f the fllwing: (1) T any ne f the individual grunding electrdes described in (A)(1), (A)(2), (A)(3), r (A)(4). (2) If the building r structure served has n grunding means, as described in (B)(2) r (B)(3)(1), t any ne f the individual grunding electrdes described in (A)(7) and (A)(8) r t a grund rd r pipe nt less than 1.5 m (5 ft) in length and 12.7 mm (1/2 in.) in diameter, driven, where practicable, int permanently damp earth and separated frm lightning prtectin system cnductrs as cvered in and at least 1.8 m (6 ft) frm electrdes f ther systems. Steam r ht water pipes r air terminal cnductrs (lightning-rd cnductrs) lightning prtectin system cnductrs shall nt be emplyed as electrdes fr nn-current-carrying metallic members. Reasn fr the Change The term air terminal cnductrs (lightning-rd cnductrs) was replaced with the brader term lightning prtectin system cnductrs t clarify that n lightning prtectin system cnductrs shuld nt be used as a part f the grunding electrde cnductr r as a grunding electrde fr ptical fiber systems. CHAPTER 8: COMMUNICATIONS SYSTEMS ARTICLE 810 Radi and Televisin Equipment Grunding f Radi and TV Equipment Grunding. (Radi and Televisin Equipment) Masts and metal structures supprting antennas shall be grunded in accrdance with unless the antenna and its related supprting mast r structure are within a zne f prtectin defined by a 46 m (150 ft) radius rlling sphere. Infrmatinal Nte: See f NFPA , Standard fr the Installatin f Lightning Prtectin Systems, fr the applicatin f the term rlling sphere. Reasn fr the Change Grunding f masts and metal supprting structures fr radi and televisin antennas can be eliminated when the antenna and its related supprting mast r structure are within a zne f prtectin defined by a 46 m (150 ft) radius rlling sphere described in NFPA , Standard fr the Installatin f Lightning Prtectin Systems. ARTICLE 840 Premises-Pwered Bradband Cmmunicatins Systems Netwrk Terminals Definitins (Premises-Pwered Bradband Cmmunicatins Systems) Optical Netwrk Terminal (ONT). A device that cnverts an ptical signal netwrkprvided signals (ptical, electrical, r wireless) int cmpnent signals, including vice, audi, vide, data, wireless, ptical, and interactive service electrical services, and is cnsidered t be a netwrk interface equipment device n the premises that it is cnnected t a cmmunicatins service prvider and is pwered at the premises. Reasn fr the Change The scpe f Article 840 nw advises that the article cvers premises-pwered bradband cmmunicatins systems that cnsist f an ptical fiber, twisted pair, r caxial cable t the premises supplying a bradband signal t a netwrk terminal. The term Netwrk Terminal is defined at and replaces the term, Optical Netwrk Terminal (ONT) Unlisted Wires and Cables Entering Building 2017 NEC Significant Cde Changes Part 5 24

27 Unlisted Wires and Cables and Raceways Entering Buildings. (Premises-Pwered Bradband Cmmunicatins Systems) The requirements f shall apply Installatins f unlisted cables entering buildings shall cmply with (A), (B), r (C), as applicable. (A) Optical Fiber Cables. Installatins f unlisted ptical fiber cables entering buildings shall cmply with (B) Cmmunicatins Wires and Cables. Installatins f unlisted cmmunicatins wires and unlisted multipair cmmunicatins cables entering buildings shall cmply with (C) Caxial Cables. Installatins f unlisted caxial cables entering buildings shall cmply with Reasn fr the Change Premises-pwered bradband cmmunicatins system wires and cables will nw be required t cmply with fr unlisted ptical fiber cables entering buildings, fr unlisted cmmunicatins wires and unlisted multipair cmmunicatins cables entering buildings, and fr unlisted caxial cables entering buildings Pwering Circuits Part VI. Premises Pwering f Cmmunicatins Equipment ver Cmmunicatins Cables (Premises- Pwered Bradband Cmmunicatins Systems) Pwering Circuits. Cmmunicatins cables, in additin t carrying the cmmunicatins circuit, shall als be permitted t carry circuits fr pwering cmmunicatins equipment. Where the pwer supplied ver a cmmunicatins cable t cmmunicatins equipment is greater than 60 watts, cmmunicatin cables and the pwer circuit shall cmply with where cmmunicatins cables are used in place f Class 2 and Class 3 cables. Reasn fr the Change New requirements were added at giving permissin fr cmmunicatin cables t carry circuits fr pwering cmmunicatins equipment. This sectin ges n t indicate that where the pwer supplied ver a cmmunicatins cable is greater than 60 watts, cmmunicatin cables and the pwer circuit must cmply with new where cmmunicatins cables are used in place f Class 2 and Class 3 cables. CHAPTER 9: TABLES AND ANNEX D Chapter 9 Tables Chapter 9, Ntes t Tables, Nte 9 Chapter 9 Tables Ntes t Tables (9) A multicnductr cable, ptical fiber cable, r flexible crd f tw r mre cnductrs shall be treated as a single cnductr fr calculating percentage cnduit r tubing fill area. Fr cables that have elliptical crss sectins, the crsssectinal area calculatin shall be based n using the majr diameter f the ellipse as a circle diameter. Assemblies f single insulated cnductrs withut an verall cvering shall nt be cnsidered a cable when determining cnduit r tubing fill area. The cnduit r tubing fill fr the assemblies shall be calculated based upn the individual cnductrs. Reasn fr the Change New text was added t Nte 9 f the Chapter 9 tables t clearly specify that assemblies f single insulated cnductrs withut an verall cvering are nt t be cnsidered a cable when determining cnduit r tubing fill area. The cnduit r tubing fill fr the assemblies is t be calculated based upn the individual cnductrs. Infrmative Annex D Example D3 Stre Building 2017 NEC Significant Cde Changes Part 5 25

28 Infrmative Annex D, Example D3 A stre 50 ft by 60 ft, r 3000 ft2, has 30 ft f shw windw. There are a ttal f 80 duplex receptacles. The service is 120/240 V, single phase 3-wire service. Actual cnnected lighting lad is 8500 VA. *In the example, 125% f the actual cnnected lighting lad (8500 VA 1.25 = 10,625 VA) is less than 125% f the lad frm Table , s the minimum lighting lad frm Table is used in the calculatin. Had the actual lighting lad been greater than the value calculated frm Table , 125% f the actual cnnected lighting lad wuld have been used. Minimum Size Feeder (r Service) Overcurrent Prtectin [see r ] 32,450 VA 240 V = 135 A The next higher standard size is 150 A (see 240.6). Reasn fr the Change The 125% fr the actual cnnected lighting lad has been remved as cntinuus lads are calculated at 125% in the Minimum Size Feeder (r Service) Overcurrent Prtectin. Infrmative Annex D, Example D7 Sizing f Service Cnductrs fr Dwelling(s) Example D7 Sizing f Service Cnductrs fr Dwelling(s) [see310.15(b)(7)] Service cnductrs and feeders fr certain dwellings are permitted t be sized in accrdance with (B)(7). With N Required Adjustment r Crrectin Factrs If a 175-ampere service rating is selected, a service cnductr is then sized as fllws: 175 amperes 0.83 = amperes per (B)(7). If n ther adjustments r crrectins are required fr the installatin, then, in accrdance with Table (B)(16), a 1/0 AWG Cu r a 3/0 AWG Al meets this rating at 75 C (167 F). With Required Temperature Crrectin Factr If a 175-ampere service rating is selected, a 2017 NEC Significant Cde Changes Part 5 26

29 service cnductr is then 175 amperes 0.83 = amperes per (B)(7). If the cnductrs are installed in an ambient temperature f 40 C (104 F), the cnductr ampacity must be multiplied by the apprpriate crrectin factr in Table (B)(2)(a). In this case, we will use an XHHW-2 cnductr, s we use a crrectin factr f 0.91 t find the minimum cnductr ampacity and size: x.91 = amperes In accrdance with Table (B)(16), a 2/0 AWG CU r a 4/0 AWG AL wuld be required. If n temperature crrectin r ampacity adjustment factrs are required, the fllwing table includes cnductr sizes calculated using the requirements in (B)(7). This table is based n 75 C terminatins and withut any adjustment r crrectin factrs. Reasn fr the Change Infrmative Annex Example D7 was revised t give tw examples fr sizing dwelling unit service cnductrs. The previus D7 is identified as an example with n required adjustment r crrectin factrs, and a new example was added t illustrate the methd used when temperature crrectin factrs are invlved. The new example calculates the size fr dwelling unit service cnductrs with the allwed (B)(7) eighty-three percent adjustment alng with a temperature crrectin factr frm Table (B)(2)(a). Infrmative Annex D, Example D8 Mtr Circuit Cnductrs, Overlad Prtectin, and Shrt-Circuit and Grund-Fault Prtectin Example D8 Mtr Circuit Cnductrs, Overlad Prtectin, and Shrt-Circuit and Grund-Fault Prtectin (see 240.6, 430.6, , , , , , and , Table , and Table ) Determine the minimum required cnductr ampacity, the mtr verlad prtectin, the branch-circuit shrt-circuit and grund-fault prtectin, and the feeder prtectin, fr three inductin-type mtrs n a 480-V, 3-phase feeder, as fllws: (a) One 25-hp, 460-V, 3-phase, squirrel-cage mtr, nameplate full-lad current 32 A, Design B, Service Factr 1.15 (b) Tw 30-hp, 460-V, 3-phase, wund-rtr mtrs, nameplate primary full-lad current 38 A, nameplate secndary full-lad current 65 A, 40 C rise. Feeder Shrt-Circuit and Grund- Fault Prtectin (a) Example Using Nntime Delay Fuse. The rating f the feeder prtective device is based n the sum f the largest branch-circuit prtective device (example is 110 A) fr the specific type f device prtecting the feeder: 300% 34 A = 102 A (therefre the next largest standard size, 110 A, wuld be used) plus the sum f the full-lad currents f the ther mtrs, r 110 A + 40 A + 40 A = 190 A. The nearest standard fuse that des nt exceed this value is 175 A [see and (A)]. (b) Example Using Inverse Time Circuit Breaker. The largest branch-circuit prtective device fr the specific type f device prtecting the feeder, 250% 34 A = 85 A. The next larger standard size is 90 A, plus the sum f the fulllad currents f the ther mtrs, r 90 A + 40 A + 40 A = 170 A. The nearest standard inverse time 2017 NEC Significant Cde Changes Part 5 27