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Wiring of the Distribution Board (Single Phase Supply From Utility Pole & Energy Meter to the Consumer Unit)

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.

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

Wiring of the Distribution Board (Single Phase Supply From Utility Pole & Energy Meter to the Consumer Unit
Wiring of the Distribution Board (Single Phase Supply From Utility Pole & Energy Meter to the Consumer Unit

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.

Wiring Color Code:

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.

(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.

Electrical Wiring Diagram of a 230V Single Phase, 63A Distribution Board (Consumer Unit) for AC Units, Lighting & 13A Circuits
Electrical Wiring Diagram of a 230V Single Phase, 63A Distribution Board (Consumer Unit) for AC Units, Lighting & 13A Radial Circuits

You may also check the related Electrical Wiring Installation Tutorials given below.



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  3. sir i am a hvac engineer but i am so keen to get electrical knowledge.. this material is very easy to understand as u have given figures along with explanation. thank you so much sir.

    1. Electrical Technology says:

      Thanks for appreciation

  4. Mukhlis Abdul Hadi says:

    thank you very much for this clear information. i have an Question. if i have load with 120A all single phase how i chose the right 3ph cable? because i have DB supplied with 3ph?<br />thank you

  5. Decent Vusi Dube says:

    I added a geaser on my Db Boxer but now it trips the main meter box not earth leakage what would be the couse?

  6. Decent Vusi Dube says:

    Thanx for this website it so helpful

  7. Play inaivmftore for me, Mr. internet writer.

  8. Khathu Maphaha says:

    great website for inexperience technicians

  9. am so glad to learn more about electricity………………………KEEP IT UP

  10. I want to wire one double pole 20amp breaker to six lighting points plus six socket outlets …..please explain with a wiring diagram. I will appreciate.

  11. kindly explain a how to design 3 phase distribution board with protection devices

  12. Diwas Poudel says:

    Thanks a lot lot lot…. your ways of explaining the topic is better than other sites. image diagram of house wiring also matched in my house (Nepal,jhapa) as well.

  13. Diwas Poudel says:

    thanks a lot……

  14. Can’t we connect the load wires to the top of the mcbs? I have seen lot of guys connecting the load wires from the bottom of the mcb. Is there anything special in that??.(I have heard it’s because to the correct function of the short circuit solenoid of the mcb).Is that correct??

  15. Thank very much….. I really appreciate…….
    I want to know how to connect two ways switch wit intermiddia switching

  16. Jeremiah Thomas says:

    These information are helpful to me I’ve been able to complete my home works and project on time ..thanks very much

  17. Tyson Luseno says:

    Hello how are you sir I’m a electricity learner and I will like to learn new electrical engineering technology and shape my knowledge

  18. Thank you for the wiring guide.

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