Electrical Wiring Installation of the Distribution Board (Single Phase Home Supply from Utility Pole & Energy Meter to the Consumer Unit)
How to Wire a Distribution Board?
Distribution Board aslo know as “Panel Board”, “Switch & Fuse Board” or “Consumer Unit” is a box installed in the building containing on protective devices, such as circuit breaker, fuses, isolator, switches, RCDs and MCBs etc. The electric main supply (230V AC & 120V AC in US) is connected through secondary of the transformer (3, Phase 4 Wire System), single phase energy meter and MCBS (DP & SP) to Sub Circuits and Final Sub Circuits to protect all the connected electrical devices and appliances through electrical Wiring installation.
- Related Wiring Tutorial: Wiring of the Distribution Board with RCD (Single Phase Supply From Utility Pole & Energy Meter to the Consumer Unit)
In the following single phase electrical wiring for home supply, We used 63A MCB (DP), 63A RCD (DP) and different rating if MCBs (SP) such as 20A, 16A, 10A etc according to your need.
In the fig below for single phase electric home supply installation and wiring of a distribution board, you may see the the single phase electric supply (230V AC and 120V AC for US) service mains i.e. Line (Red) and Neutral (Black) carrying single phase supply from transformer secondary and utility pole (3 Phase, 4 Wire (Star) System) to the single phase energy meter.
Related Wiring Tutorials:
Both the Live and Neutral wires go to the Main Double Pole Circuit breaker. The Live from DP MCB then connected to the common busbar segment for MCBS which is directly connect to the Single Pole Circuit breaker. The outgoing of the SP MCBS are connected to the sub circuits, final sub circuits and electrical devices and appliances then.
The Neutral from the Main DP MCB is connected to the Neutral Link and the outgoings wires are connected to the sub, final sub circuits and electrical appliances. Keep in mind all the electrical devices and appliances should be connected to the Earth Link for safety which is directly connected to the earth electrode and earth plate for proper earthing and grounding.
Below is a Wiring diagram of the distribution board , Single phase electric supply from electric pole and Energy meter to the main distribution board (Without RCD = Residual Current Devices).
Click image to enlarge
While we have already discussed the distribution board, types of distribution boards such as Main Distribution Board (MDB), Sub Distribution Board (SDB), Final Distribution Board (FDB), Sub Circuits and Final Sub Circuits in the previous post, Therefore, We will only discus the main electrical wiring accessories used in this basic Single Phase Home Supply Main Distribution Board Installation.
We have used Red for Live or Phase , Black for Neutral and Green for Earth Wire. You may use the specific area codes i.e. IEC – International Electrotechnical Commission (UK, EU etc) or NEC (National Electrical Code [US & Canada] where; NEC: Single Phase 120V AC: Black = Phase or Line, White = Neutral and Green/Yellow = Earth Conductor Three Phase 208 AC: Black = Phase 1 or Line1, Red= Line 2, Blue= Line 3, White / Gray = Neutral and Green/Yellow = Earth Conductor IEC: Single Phase 230V AC: Brown= Phase or Line, Blue= Neutral and Green = Earth Conductor Three Phase 208 AC: Grey= Phase 1 or Line1, Black= Line 2, Brown= Line 3, Blue = Neutral and Green= Earth Conductor
We have used Red for Live or Phase , Black for Neutral and Green for Earth Wire. You may use the specific area codes i.e. IEC – International Electrotechnical Commission (UK, EU etc) or NEC (National Electrical Code [US & Canada] where;
Single Phase 120V AC:
Black = Phase or Line, White = Neutral and Green/Yellow = Earth Conductor
Three Phase 208 AC:
Black = Phase 1 or Line1, Red= Line 2, Blue= Line 3, White / Gray = Neutral and Green/Yellow = Earth Conductor
Single Phase 230V AC:
Brown= Phase or Line, Blue= Neutral and Green = Earth Conductor
Three Phase 208 AC:
Grey= Phase 1 or Line1, Black= Line 2, Brown= Line 3, Blue = Neutral and Green= Earth Conductor
Requirement to Wire a Single Phase Distribution Board
- DP = Double Pole MCB (The main isolator or main switch).
- SP = Single Pole MCB (Circuit Breakers and Fuses).
- MCB & CB = Miniature Circuit Breaker and Circuit Breaker.
Related Electrical Wiring Guide: How To Wire a 3-Phase kWh Energy meter?
DP = Double Pole MCB (The Main Switch)
This allows you to turn OFF and ON the electric supply to your home as it is is the main operating switch to control & manage the flow of electric supply in the wiring system. By using the Main Switch, you may be able to immediately switch OFF the electric supply in the home in case of emergency i.e. electric shock, fire, short circuit or while working on main board to troubleshoot or maintenance of the system. Multiple Main switch and fuse board can be used in case of many supply units i.e. for different floors etc.
- Related Wiring Tutorial: Staircase Wiring Circuit Diagram – How to Control a Lamp from 2 Places by 2-Way Switches?
(CB) Circuit Breakers (SP)
Circuit breaker is a device which switch OFF the circuit from electric supply at abnormal and make the circuit in normal conditions same as fuse. These are automatic protection devices in the Main switch board or fuse-box that switch off a circuit if they detect a fault. the size of the fuse and Circuit Breaker are similar, but using circuit breaker instead of fuse make sense due to automatic operation. In addition, you may be able to reset it again if it trips ever.
You may also check the related Electrical Wiring Installation Tutorials given below.
- Single-Phase Electrical Wiring installation in a Multi-Story Building
- Three-Phase Electrical Wiring installation in a Multi-Story Building
- Three Phase Electrical Wiring Installation in Home
- Wiring the Distribution Board with RCD (Residual Current Devices) – Single Phase Home Supply
- Basic Homr Electrical Wiring Installation Diagrams & Tutorials