House Wiring

House wiring diagrams are given in this section which will be useful during electrification work in a building. Following points must remember while doing wiring –

  • MS or PVC conduit is used for house wiring,
  • The size of conduit depends on the number & size of wires,
  • Two types of conduiting are done -1) Surface & 2) Concealed,
  • Sub-Mains– Submain is a set of wires which is laid between the DB (Distribution Board) of the house & metering panel. The size of submains should be capable to carry current of total load which is connected with DB. Sub-mains are of two types –a) Three phase submains (3-phase wires R,Y,B + 1-neutral wire + 1- earth wire) & Single phase submains (1-phase wire + 1-neutral wire +1- earth wire). It depends on the type of three & single phase DB.
  • Main Circuit– It is a set of 3 wires (1-phase, 1-neutral & 1-earth) which is laid inside the conduit between DB & first switch box. First switch box may be for lighting purpose or for switch& socket. Main circuit for light & light plug is fed from 10A MCB. Maximum 800W load can be connected with one main circuit or maximum 10 nos of points can be connected with one circuit. While main circuit for power point (16A switch & socket) is fed from 16A MCB.
  • Half wire – It’s a phase wire which is laid between switch & light point,
  • point– It’s either a light or power point where light or equipment are connected. Light is connected with light point & equipment is connected with power points.
  • Light plug – Light plug is a set of 6A switch & socket which is used for low current portable equipments like TV, RO, portable fan, mobile charger etc. Light plug is fed with 10A MCB or may be looped with light point.
  • Power plug – Its set of 16A switch & socket which is used for high current portable equipments like domestic iron, geyser, refrigerator, AC, Heater etc. Power plug is fed from 16A/20A/25A depending upon the type of load.
  • Loop point – Loop point is secondary point which is connected/looped with main circuit. Next loop point may be connected with first loop point & so on.

Light wiring has been explained in the drawing given below  –

Wiring diagram for individual items – In this section, wiring diagram of individual items has been given below for reference purpose –

Current carrying capacity of Copper wires

Size of Cu wire (in sq mm) Current (in Ampere)
1.o 11
1.5 14
2.5 19
4.0 26
6.0 31
10.0 42
16.0 57
25.0 71
35.0 91
50.0 120
70.0 160
(Note– Current carrying capacity may slightly vary according to different manufacturers.)