Circuits in a distribution box are connected by routing the incoming power to the main MCB, then through protective devices like RCCBs, and finally to individual branch circuit breakers, with neutral and earth wires properly linked.

Step-by-Step Connection

1. Turn Off Main Power: Always ensure the main power supply is switched off before starting any connections to prevent electrical shock . 2. Mount the Distribution Box: Secure the box at an accessible height on a stable wall, ensuring there are no obstructions . 3. Connect Incoming Power:

• Attach the incoming live (phase) wire to the main MCB (usually a double-pole MCB for single-phase systems).
• Connect the neutral wire to the neutral link.
• Connect the earth wire to the earth link . 4. Connect Protective Devices:
• If using an RCCB, connect the output of the main MCB to the input of the RCCB.
• The output of the RCCB then feeds the branch MCBs.
• For double-pole branch MCBs, connect both phase and neutral wires; for single-pole MCBs, connect only the phase wire, while the neutral goes to the neutral link . 5. Connect Branch Circuits:
• Each branch circuit wire is connected to its corresponding MCB.
• The phase wire goes to the MCB terminal, the neutral wire to the neutral link, and the earth wire to the earth link .
• Arrange MCBs from left to right, leaving reserved positions on the right if needed . 6. Wire Management:
• Use appropriate wire sizes according to load (e.g., 2.5mm² for lighting and sockets, 4mm² for air conditioning).
• Bind wires neatly with plastic ties and maintain proper spacing.
• Ensure wires are color-coded: phase (yellow/green/red), neutral (blue), earth (green/yellow) for clarity and safety . 7. Testing and Safety Checks:
• After wiring, use a multimeter to verify connections and check for short circuits.
• Confirm that all breakers, fuses, and protective devices are correctly installed and rated for the load .
• Ensure the box is dry, ventilated, and easily accessible. By following this sequence, you ensure that incoming power is safely distributed through protective devices to all branch circuits, with proper neutral and earth connections, minimizing the risk of overloads, short circuits, or electrical hazards.