Choice of earth leakage protection devices

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1 Protection Choice of earth leakage protection devices DB DB DB Choice of sensitivity The sensitivity of an earth leakage protection device depends mainly on the function it has to perform: Protection from electric shock y direct contact. Protection from electric shock y indirect contact. The following tale gives a reminder of: The s that must e protected against these various risks (oligation or recommendation). The type of earth leakage protection device to e used in each case, its sensitivity, and its location in the distriution diagram. Type of protection Oligations National standard International standard IEC Protection from electric shock y direct contact Power supply for General-purpose power sockets, up to 20 A Appliances in the vicinity of a athtu, shower, pond or swimming pool Portale appliances for outdoor use, up to 32 A Lighting for exhiition stands and shows Outdoor lighting national oligations (aove) Protection from electric shock y indirect contact The entire power distriution system, except for devices: With class II insulation Operating at Safety Extra Low Voltage (class III) national oligations (aove) High-risk premises: v explosion (BE3) v Agricultural and horticultural uildings Equipment for fairs, exhiitions and shows Temporary outdoor recreational installations national oligations (aove) Recommended y Schneider Electric Lighting in the home distriution switchoard 30 ma (*) 100 ma to 3000 ma (depending on the earthing system) Residual current device protecting a Residual reaker protecting a distriution switchoard Dilapidated uildings or electrical installations Humid atmospheres: agricultural uildings, pulic swimming pools Presence of chemical agents Residual current reaker or device, on incoming feeder Setup in sudistriution oard or main switchoard Residual current device protecting a Residual current device or reaker protecting a On incoming feeder: residual reaker or device 300 ma (or 500 ma) distriution switchoard Residual current reaker or device, on incoming feeder Setup in sudistriution oard or main switchoard Residual current device protecting each to a highrisk zone Residual current device or reaker protecting a On incoming feeder: residual reaker or device without eing ale to get free. Example: healthcare equipment for hospital eds. Generally, devices with this very high sensitivity are liale to cause frequent tripping, due to the natural leakage currents of the installation. 140 Version : /09/2013 CA902000E

2 Protection Choice of earth leakage protection devices (cont.) DB DB DB DB Interference immunity Schneider Electric provides various equipment technologies capale of overcoming the consequences of interference of all kinds. Operating conditions Examples Types AC A SI B Loads Discrimination Residual current devices of average sensitivity (100 ma and more) are availale in a selective (s) and delayed (R) version. This option ensures that, in the event of an earth fault downstream of the installation, only the defective part is switched off. The tale elow shows (in green) which upstream/downstream equipment cominations provide this discrimination. Sensitivity (ma) - Downstream s or R With no special characteristics Including a Single phase Three phase Generating high-frequency interference (current peaks, harmonics) in the power supply Electrical environment Vicinity of equipment generating transient overvoltages Circuits powered y an uninterruptile power supply "Isolated neutral" (IT) earthing system Major risk of lightning strokes Atmosphere Amient temperature which could e less than -5 C Presence of corrosive agents (AF2 to AF4) or dust (1) SiE for C120 and NG125 -reakers General-purpose power sockets Incandescent lighting Household appliances: microwave oven, dishwasher, clothes dryer Electric heating, water heater Household appliances: induction cooking appliances, washing machines (variale speed) Single-phase variale speed drives Three-phase variale speed industrial drives Three-phase uninterruptile power supplies Fluorescent lighting powered y extra low voltage transformer, y electronic allast Variale luminosity lighting Powerful IT equipment Single-phase variale speed industrial drives Air conditioning Telecommunications equipment Capacitor anks Microcomputer systems Computer peripherals (printers, scanners, etc.) Sensitivity (ma) - Upstream Instantaneous Selective s Delayed R Instantaneous Selective s Delayed R High-powered switching devices Reactive energy compensation anks Backed-up networks Buildings protected y a lightning protection system Mountainous or humid regions Regions with high keraunic level Indoor swimming pools Yacht harours, marinas, camping grounds Water treatment Chemical industries, heavy industries, paper mills Mines and cellars, road tunnels Markets, stock raising, food processing industries (1) CA902000E Version : /09/

3 of high-sensitivity All the high-sensitivity (30 ma) in the Acti 9 range conform to the IEC/EN and IEC/EN standards. The response times defined y these standards guarantee their effectiveness in protecting people against direct contacts. The response time of a residual current device is the time etween the appearance of a dangerous leakage current and the interruption of the. Fault current (ma) 15 ma No tripping 30 ma 300 ms 60 ma 150 ms 150 ma 40 ms Maximum response time (ms) IEC/EN and IEC/EN standards. They guarantee protection of people against direct contacts for the following reasons : When a person comes into direct contact with a live conductor, the current passes directly through the human ody. Residual current device This current, with the same magnitude, is detected y the residual current device. Zones AC-1 to -3 No danger Zone AC-4 Danger (IEC 60479) maxi 30 ma (IEC 61008/61009) C1 The IEC technical report studies the sensitivity of the human ody to the the current causes injury to a person. Superimposing the two curves shows that the aove response times protects the users. Measuring the response time If the user wishes to check the response time of his, he estalish a leakage current of calirated magnitude measure the exact response time. Procedure The measuring instruments must conform to IEC/EN Carry out the operations in the following order safety instructions: disconnect the loads install the measuring instrument downstream of the residual current device to e tested (for example on a power outlet) perform the measurement. 666 Version : /09/2013 CA908013E

4 of medium-sensitivity of ic60 Vigi and iid60 The medium-sensitivity ( ma) in the Acti 9 range conform to IEC/EN and 61009: their response time guarantees personal protection against indirect contacts and in the case of selective versions (S), a "non-tripping time" guarantees discrimination with the installed downstream. Instantaneous Sensitivity (I n) 100 ma 300 ma 500 ma Fault current (ma) I n/ No tripping Max. response time Residual current device I n ms 2 x I n ms 5 x I n ms 500 A 40 ms Selective (S) and time-delayed (R) Sensitivity (I n) Type 100 ma 300 ma 500 ma 1000 ma Selective (S) Time-delayed (R) Fault I n/ No tripping No tripping current (ma) Non-tripping time Non-tripping time I n ms 500 ms 300 ms 1000 ms 2 x I n ms 200 ms 150 ms 500 ms 5 x I n ms 150 ms 150 ms 300 ms 500 A 40 ms 150 ms 150 ms 300 ms Time etween the appearance of a hazardous leakage current and power down. Non-tripping time For selective and time-delayed devices, the non-tripping time is the time etween the appearance of a hazardous leakage current and the device tripping. If the leakage current disappears efore this time, the device does not trip. This fast disappearance of the leakage current can e due to: the transient nature of the fault (e.g. the current generated y a switching surge) the interruption of the fault current y another faster residual current device situated downstream. Selective and time-delayed devices therefore afford the user: etter immunity against nuisance tripping total discrimination etween. CA908018E Version : /09/

5 of medium-sensitivity DB Uc Protection against indirect contacts The response times of guarantee personal protection against indirect contacts, in conformance with the requirements of the installation standards (IEC or equivalent). Indirect contacts A person who comes into contact with an accidentally live frame caused y an insulation fault experiences an indirect contact: the contact voltage Uc creates a current that passes through the human ody. Maximum reaking time The maximum reaking time required y the installation standards, in the event of an insulation fault, depends on: the network voltage the earthing system. Maximum reaking time for terminating s (ms) Earthing Network phase/neutral voltage system V V V > 400 V TN or IT TT Note: a reaking time of no more than 5 s is permitted for distriution s to ensure discrimination with the devices installed on the terminating s. This time should e reduced to the essential minimum. DB Rn = 10 Ω Neutral earth connection UA = 20 Ω Operating frame earth connection Uc L1 L2 L3 N PE These times are ased on the maximum prospective values of the contact voltage Uc and on the contact times authorised y technical report IEC Example On a three-phase phase/neutral voltage network Uo = 230 V in a TT system: In the event of an insulation fault, the leakage current Id is equal to: Uo/ (RA + Rn) Protection sensitivity The residual current device must trip as soon as the leakage current corresponds to a hazardous situation, i.e. a contact voltage of 50 V (in a dry atmosphere). Maximum reaking time For a 230 V phase/neutral voltage network in a TT system, the IEC standard requires a maximum reaking time of 200 ms. For the 2.1 A leakage current: v an instantaneous residual current device with a sensitivity of 300 ma will power down the in less than 40 ms, v an instantaneous residual current device with a sensitivity of 500 ma will power down the in less than 60 ms. Note: For well-designed and regularly maintained electrical installations, the resistance of Use of the time-delayed In accordance with the reaking times required y the installation standards (aove), the selective and time-delayed can e used in the following cases: Circuit Terminating Network voltage Residual current device (phase/neutral) Instantaneous I Selective S Time-delayed R y 230 V (1) > 230 V Su-distriution or general (1) Only in a TN system for a phase/neutral voltage < 120 V. 668 Version : /09/2013 CA908018E

Earth leakage protection Response time of medium-sensitivity residual current devices

Earth leakage protection Response time of medium-sensitivity residual current devices Response time of ic60 Vigi and iid60 The medium-sensitivity (100 1000 ma) in the Acti9 range conform to IEC/EN 61008 and 61009: bbtheir response time guarantees personal protection against indirect contacts