Wednesday, June 1, 2011

Statutory electrical requirements for high-rise buildings

1. A building that is more than 15 m in height shall be categorised as high-rise building. Height shall be taken from the floor of the highest level, where access from ground is possible. Machine room of lift, water tank etc. may be excluded.

2. Such high-rise buildings come under section 54 of The Electricity Act 2003 and Rule 50(A) of Indian Electricity Rules 1956.

3. Outdoor transformer installation is not permitted at the premises of high-rise apartment buildings. However transformer, having cable end boxes at both sides and indoor primary breaker/SFU, may be installed outside taking due care.

4. For total connected load of 50 kVA and above, separate transformer shall be installed by the owner/promoter at his own cost. Fire pump may be excluded in calculating total connected load.

5. For common and essential loads of 100 kVA and above, separate transformer with HT metering shall be installed exclusively for such loads by the consumer/promoter (at the building premises at his own cost)

6. HT load break switch fuse unit or vacuum circuit breaker shall be provided as primary controlling device, if there is only one transformer. HT load break switch fuse unit is adequate for transformers of rating below 1000 kVA. VCB is to be provided if transformer rating is 1000 kVA and above.

Note: If there is more than one transformer in the same building, HT load break isolator of approved make shall be provided at incomer side of the HT panel as group control device. For individual transformer, HT SFU or VCB shall be provided as specified in para above.

a) HT metering arrangement shall be attached to the primary control device. Time of day meter of tamper proof type shall be provided for metering. Only single core, single ratio type current transformers are permitted for metering and the consumer shall not be permitted to take any tappings from the CT secondary.

b) Tappings from PT is permitted and shall be taken with separate fuse control for connection to indication lamps, volt meter, power factor meter watt-hour meter etc.

8. Only dry type transformer of approved make shall be installed below or above ground level. (Also refer para 1 of Indoor transformer installation.)

9. At secondary side of transformer, circuit breaker of proper rating shall be provided.

10. Locking and sealing facility shall be provided in all metering panels, main switchboards, HT panel etc. to prevent theft of energy and illicit use of electricity.

11. HT panel including group control isolator, LT panels including metering panels shall be installed by the promoter/consumer at his own cost. It is the responsibility of the KSEB to effect supply up to the incoming terminal of the HT panel.

12. Energy meters for individual consumers shall be purchased and installed by the consumer/promoter at his own cost. These meters shall be got tested and certified by Electrical Inspectorate or KSEB.

13. Fuse/MCB protection shall be provided for watt-hour meters. If MCB is provided a separate door with locking facility to enable the supplier to lock it with MCB in off position, shall be provided.

14. Generator of adequate rating shall be installed to feed essentials loads; Generator capacity shall be minimum 20% of total connected load.

15. Floor wise single point supply isolation facility shall be provided. However single point isolation is permitted for two adjacent floors.

16. Maximum number of 3 phase outlets from a metering panel shall be limited to eight. Twelve numbers of single-phase outlets can be permitted.

17. For calculation of total connected load, minimum 1.2 kW shall be taken for single-phase connection and 5 kW for 3-phase connection. For residential apartments minimum 50 W shall be envisaged for one sq.m. of residential area

18. Cables shall be taken to different floors through cable duct only. There shall be access to duct from all floors. Fire barriers shall be provided in the duct at floor crossings, Generator cables and grid cables shall be segregated in the duct. No other service pipes shall be taken through electrical duct. Two numbers of earthing strips shall be taken through the duct

19. Lifts with imperforated doors shall be provided in high-rise buildings.

20. When lift is operated through generator, the capacity of generator should be 6 times the rating of lift motor in kW and 4 times in the case of variable voltage variable frequency controller.

21. Oil filled breakers/SFUs are not permitted in high-rise buildings.

22. Low set E/F protection using neutral CT is not to be insisted for transformers feeding high-rise buildings where LT metering is adopted, but ELCBs shall be provided for all DBs and motor loads except for fire pump motors.

a). Electrically operated fire pumps along with booster pumps of adequate rating shall be provided. Details are given in table 23.
b). In addition diesel engine operated fire pumps shall also be provided.

24. Metering panels shall be installed at ground floor.

25. Unmetered spare outlets shall not be permitted in MSB/SSBs/metering panels.

26. Diversity factor shall not exceed 2.

27. Lightning protection shall be provided for high-rise buildings as per IS 2309.

a). Structure having a base area not exceeding 100 m2 need have only one down conductor
b). For structure having base area exceeding 100 m2, the number of down conductors shall be the smaller of the following

(i) One plus additional one for each 300 m2 or part thereof in excess of first 100 m2.
(ii) One for each 20 m of perimeter of the structure protected.

28. Maximum number of ways in 3-phase lighting DBs shall be 8.

29. When generator supply is extended to individual consumers, it shall be through an emergency DB.

30. Emergency supply isolation facility using push buttons shall be provided in a conspicuous place at ground floor at a max. height of 2.75 m.

31. In the case of high-rise buildings where ground floor shops are owned by a number of consumers where the rest of the portion is single owned, 2 transformers shall be insisted. One belonging to the owner of the building availing HT supply and distributing the loads in the main building and the other belonging to KSEB for supplying to the individual LT consumers.

32. Transformers and generators shall be installed at the periphery of the building having easy access and ventilation.

33. Exhaust pipe of DG set shall be brought above roof top level.

34. Acoustic arrangements shall be provided for generator set to limit sound level below 70 dB outside.

35. DG sets shall be installed above ground level in high-rise apartment buildings only as per the special provisions provided in chapter titled MV Generators.

36. Rigid standards shall be followed in selection of quality wiring materials and for standard maintenance practices. Wiring shall conform to IS 732, IS 4648 and NEC.

37. Any dispute between the promoter or consumer of the high-rise building with KSEB regarding installation standards shall be referred to the Chief Electrical Inspector for decision.

38. Electric connection shall be effected to high-rise building only after getting sanction order from the Electrical Inspectorate.

39. Fee shall not be demanded for Metering panel incomer isolator/breaker.


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  2. This is great finding! Really thank you! I need this. I want to work for someday and being knowledgeable in electrical equipment will be a great advantage.

  3. In a high rise building in Kerala having many residential apartments with separate Municiapal ownership Numbers, can the builder take a single meter HT connection without the consent of the owners and can the builder collect charges from owners by supply of electricity

  4. Will the blowing of 11kV HT fuse (horn gap fuse) create a loud noise?

  5. The basic planning of the electrical works in high rise buildings starts with identifying the various requirements of the occupiers of the building, as well as the requirements of the statutory regulations.

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