Wiring Method For Distribution Box

Wiring in the distribution box is a crucial step in home renovation or electrical repair, directly impacting electrical safety. Due to the inherent risks of working with high-voltage electricity, it is strongly recommended that a professional electrician perform the work.

I. Safety Warnings

Power Must Be Disconnected: Before proceeding, disconnect the main power switch and use a voltage tester to confirm that there is no power at the incoming line terminals inside the box.

Professional Qualifications: According to national regulations, the installation of distribution boxes after the incoming power line must be performed by a certified electrician. This article is for informational purposes only.

Tools Needed: Voltage tester, Phillips/flathead screwdriver, wire strippers, crimping pliers, marker, multimeter.

II. Wiring Steps (Common Household Wiring)

1. Power Off and Voltage Test:

Disconnect the main power switch or the switch before the meter. Use a voltage tester to confirm that there is no power at the incoming terminal in the box.

2. Installation Layout:

Install switches according to circuit requirements: Main switch → Lighting → General sockets → Kitchen/bathroom residual current device (RCD) → Air conditioner → Spare.

High-power appliances should have independent circuits.

3. Incoming Wiring:
Live wire (L, usually red/yellow/green): Connect to the upper left or right side of the main switch (marked with L or a letter).

Neutral wire (N, usually blue/black): Connect to the other side of the main switch (marked with N).

Ground wire (PE, yellow-green): Connect directly to the ground busbar in the box.

4. Outgoing Wiring:
For standard lighting circuits, use a 1P circuit breaker:
Live wire: Lead from the bottom of the main switch, connecting to the top of each branch switch using a branch busbar or parallel jumper. Then lead the wires from the bottom of the branch switches to the rooms.

Neutral wire: The neutral wire is run directly from the neutral busbar to the room without passing through a branch switch.

Ground wire: The ground wire is run from the ground busbar to the room.

Residual current circuit breaker (2P or 1P+N):

Incoming terminals: Live wire is marked L, neutral wire is marked N.

Outgoing terminals: Live wire is marked L, neutral wire is marked N. Note that the neutral wire cannot be used with other circuits.

5. Wiring process

Wire end treatment: Strip approximately 10-12mm of insulation. The copper core of the wire end should not be exposed too long, and the insulation should not be pressed into the terminal.

Secure crimping: After tightening the screw, gently pull the wire end; it should not be loose.

Wire bending direction: Bend the wire end into a U-shape, with the opening direction consistent with the screw tightening direction.

Clear marking: Mark each circuit switch with a marker or label.