The incoming power line should be connected to the main MCB (or main switch) for the live wire and to the neutral bus for the neutral wire, with proper grounding to the earth link.

Step-by-Step Connection

1. Identify the Input Wires: The incoming power line typically consists of a live (phase) wire, a neutral wire, and sometimes a ground wire. In single-phase systems, the live wire carries current to the distribution box, while the neutral provides the return path, and the ground ensures safety . 2. Connect the Live Wire:

• The live (phase) wire from the utility should be connected to the input terminal of the main MCB (double-pole for 230V single-phase systems or as per local voltage standards).
• This main MCB acts as the main switch and provides overcurrent protection for the entire distribution system . 3. Connect the Neutral Wire:
• The neutral wire from the incoming supply should be connected to the neutral bus bar inside the distribution box.
• The neutral bus is also connected to the earth ground to maintain safety and prevent electrical shocks . 4. Grounding:
• The ground wire from the incoming supply or from the building's earthing system should be connected to the earth link or ground bus in the distribution box.
• The metallic body of the distribution box should also be bonded to the earth link to prevent accidental shocks . 5. Connection to Protective Devices:
• The output of the main MCB is connected to the input of the RCCB (Residual Current Circuit Breaker) if installed.
• From the RCCB, the power is distributed to individual single-pole or double-pole MCBs for each circuit.
• The neutral from the RCCB output is connected to the neutral bus, and the earth wire is connected to the earth link . 6. Safety Checks:
• Ensure all connections are tight, properly insulated, and color-coded according to local electrical standards.
• Perform a visual inspection and multimeter test before switching on the main supply . By following this sequence, the incoming power is safely routed through the main protective devices, and the distribution box can reliably supply electricity to all circuits while maintaining proper grounding and safety.