Question

The cross-sectional area of a conductor for power wiring should NOT be less than ______ for a copper wire and ______ for aluminium.
1. 1.50 mm², 2.50 mm²
2. 1.0 mm2, 1.50 mm2
3. 1.0 mm2, 1.0 mm2
4. 2.50 mm2, 1.50 mm2

Answer 1

Correct Answer - Option 1 : 1.50 mm², 2.50 mm²

Indian electricity rules regarding internal wiring:

• The minimum size of conductor used in domestic wiring must not be of a size less than 1/1.12 mm2 in copper or 1/1.40 mm (1.5 mm) in the aluminum wire.
• The height at which the meter board, the main switchboard is to be fitted 1.5 meters from ground level. The casing will be run at a height of 3.0 meters room ground level.
• The light brackets should be fixed at a height of 2 to 2.5 meters from ground level.
• The maximum number of points in a sub-circuit is 10.
• The maximum load in a sub-circuit is 800 W.

 

I.E. Rules regarding power wiring:

1. In a power sub-circuit, the load is normally restricted to 3000 watts and a number of outlets to two in each sub-circuit.
2. All equipment used in power wiring shall be iron clad construction and wiring shall be of the armored cable or conduit type.
3. The length of flexible conduit used for connections between the terminal boxes of motors and starters, switches, and motors shall not exceed 1.25 meters.
4. Every motor regardless of its size shall be provided with a switch fuse placed near it.
5. The minimum cross-sectional area of the conductor, that can be used for power wiring of 1.25 mm2 for copper conductor cables and 1.50 mm2 for Aluminium conductor cables (refer ISI recommendations). Hence VIR or PVC cables of size lower than 3/0.915 mm copper or 1/1.80 mm Al can not be used for motor wiring.
6. For motors below 15 BHP which have a very heavy starting current, a fuse should be of current rating to carry the starting current of motor safely and cable should be of current rating not lower than half of the current rating of the fuse.

 

From the above options, the cross-sectional area of a conductor for power wiring should NOT be less than 1.50 mm2 for a copper wire and 2.50 mm2 for aluminium.