June 2014 Welcome Express. to our e-rew Express. In view of the increasing number of rewiring works in recent years, we would like to share with you the advisory services on rewiring works of existing buildings in this issue of e-rew We hope you will find the information useful and handy. If you have any suggestion, please send an email to us at mail@hkelectric.com or contact our Customer Installation Section at 2887 3455 so that we can further improve our service. Advisory Services on Rewiring Works of Existing Buildings In order to facilitate our customers and their Registered Electrical Workers (REWs) in completing the rewiring work properly, HK Electric is offering the following services: 1. Technical Advisory Service When you are planning to carry out rewiring work on the building s communal installation, we can provide you with technical advice on: - your rewiring work and proposed schematic electrical design - interface requirement between HK Electric supply equipment and customer installation - meter duct / room layout and meter position 2. Approved Loading Enquiry Service If replacement of main switch is required during rewiring work, the customer and REW may need to know the approved loading of an installation. In this connection, the customer may complete a C.I. 141 Form, Approved Loading Enquiry as shown in Appendix I, to make enquiry of the approved loading with us before commencement of work. 3. Request for Shutdown of HK Electric Supply Service If it is necessary to isolate HK Electric s supply source in order to facilitate the rewiring work, you should first obtain the written agreement from all the affected tenants and provide us a C.I. 509 Form, Request for Temporary Shutdown of Supply as shown in Appendix II, at least two weeks before the shutdown date. Please be reminded that the shutdown schedule may have to be re-scheduled if there is any objection from other affected customers. 4. Meter Duct / Room and Meter Board Design Advisory Service In connection with your rewiring work, we can also provide advice / comment on your proposed design of meter duct / room and meter board position layout drawings.
Many old buildings do not have meter duct / room or switch room. The meters and most of the electrical wirings are installed in the communal area. Some property management companies and contractors would arrange to re-install the meters and electrical equipment inside fire resistant cubicles in the course of rewiring work. Very often, this arrangement causes difficulty on our meter reading and maintenance work of our equipment afterwards. To prevent this problem and avoid the subsequent rectification work, meter cubicle should be designed to have hinged door and equipped with transparent window to facilitate meter reading and maintenance. The detailed requirements are stipulated below for your reference: Meter Type Main Switch Minimum Clearance for Meter Board Dimension Meter Cubicle (MC) Dimension Rating (Amp) Meter Termination (A) Height (H) Width (W) Height H(MC) Width W(MC) 1-ph 60 150 280 210 x N 355 (210 x N) + 140 3-ph 125 200 440 300 x N 515 (300 x N) + 140 Notes: Meter Cubicle Requirement a. The meter cubicle / enclosure (including the transparent glass window) shall comply with the relevant fire regulations. b. The distance between meter surface to the hinged door at closed position shall be maximum 50mm and minimum 20mm. c. Meter cubicle / enclosure for more than one meter shall be of dimensions in multiples of unit per the above table. N is number of meter. d. If other related electrical equipment is required to be installed inside the meter cubicle / enclosure, then the size of the meter cubicle / enclosure shall be enlarged accordingly. e. Recommended size of address label : 120 x 60mm 2. f. All dimensions are in mm. 2
Prior to the large scale erection of meter cubicles, we strongly recommend customers/rews liaise with our engineers at 2887 3455 for a mock-up inspection in order to identify any problems in advance. 5. Address Label and Cross Connection Check Sheet Printing Service After the completion of rewiring work by customers/rews, cross connection of meter leads / tails are occasionally identified during our quality check and subsequent resealing work of tariff meters. Such cross connection would result in the improper determination of electricity consumption. Under normal situation, the meter leads / tails should be properly connected to the corresponding premises as illustrated below: However, if prior preparation is not well-planned, some possible scenarios may arise from rewiring work as follows: i. Meter Leads Cross Connected 3
ii. Meter Tails Cross Connected As a measure to tackle the potential cross connection issue, we will provide printed address labels with corresponding meter numbers for easy identification of service addresses at site. Cross connection check sheets will also be provided for verification of correct connection of meter tails / main wires after the rewiring work. You are advised to follow the steps below for your rewiring work: i. Before starting your project, inform us as early as possible so that we could prepare the address labels and cross connection check sheets for you. ii. Collect the address labels and the cross connection check sheets from our Customer Centre. Before starting the rewiring work, check carefully against each meter number and service address and attach the address labels to the corresponding meter tails / main wires accordingly. iii. Based on the information on the address labels, connect the meter tails / main wires to the corresponding meters. Address Label and Cross Connection Check Sheet iv. Make use of the cross connection check sheets to verify that meter tails / main wires are correctly connected to the corresponding premises. v. After the rewiring work is completed, please provide us with a copy of your duly completed Work Completion Certificate, as fitted drawing and the cross connection check sheets for our arrangement of re-sealing of meters. We are pleased to provide our advisory service to customers/rews regarding rewiring work and you are welcomed to provide us with the schematic wiring diagram and proposed layout plan of meter room for our consideration. Simply call our hotline at 2887 3455 for enquiry. 4
Appendix I - C.I. 141 Form Approved Loading Enquiry 5
Appendix II - C.I. 509 Form Request for Temporary Shutdown of Supply 6