How to wire the power supply light in the distribution box

A power supply indicator light can be safely wired across the output of the main MCB or after the RCCB to show when the distribution box is live.

Choosing the Indicator Light

Use a 230V AC-rated pilot light for domestic single-phase systems (or 110–120V AC in the US). LED pilot lights are preferred for low power consumption and long life.

Connection Points

1. Across the Main MCB Output: Connect the phase (live) wire from the output terminal of the main MCB to the live terminal of the indicator light. Connect the neutral wire from the neutral busbar to the neutral terminal of the light. This ensures the light turns on whenever the main MCB is switched on .
2. After the RCCB: Alternatively, you can connect the light across the output of the RCCB. This method ensures the indicator only lights when the circuit is protected and live .

Wiring Steps

1. Turn off the main supply before working inside the distribution box to prevent electric shock .
2. Identify the phase and neutral terminals on the main MCB or RCCB.
3. Connect the phase wire from the MCB/RCCB output to the live terminal of the pilot light.
4. Connect the neutral wire from the neutral busbar to the neutral terminal of the pilot light.
5. Secure the wires neatly and ensure proper insulation to avoid accidental contact.
6. Optionally, mount the pilot light on the distribution box cover for easy visibility.

Safety Considerations

• Always use wires rated for the system voltage (e.g., 1.5mm² for small indicator circuits in 230V AC systems).
• Ensure the indicator light is fused or connected through a small MCB if required.
• Verify connections with a multimeter before switching on the main supply.
• Never connect the light directly to the phase without a neutral return, as this can create a short circuit or shock hazard. By following these steps, the power supply light will reliably indicate when the distribution box is live, enhancing safety and convenience in your electrical system .