Sub-meter distribution box connection

A sub-meter is connected to a distribution box by linking the main supply through protective devices to the meter, then distributing power to individual loads with proper neutral and earth connections.

Overview of Connection

A sub-meter allows monitoring of electricity consumption for a specific circuit or unit. To connect it to a distribution box:

1. Main Supply Connection: Identify the main power supply entering the distribution box. Connect the phase (live) and neutral wires to the input terminals of the main MCB or breaker that will feed the sub-meter .
2. Protective Devices: The output of the main MCB is connected to an RCCB (Residual Current Circuit Breaker) for safety. From the RCCB, the output wires are routed to the sub-meter and then to the load MCBs .
3. Sub-Meter Wiring: Single-phase sub-meters typically have four wires: live (L), neutral (N), and two protective earth/ground wires. Connect the live and neutral from the RCCB output to the corresponding terminals on the sub-meter. Ensure the earth wire is connected to the distribution box's earth link .
4. Load Distribution: From the sub-meter, connect the output terminals to the load MCBs. For single-pole MCBs, connect only the phase wire to the MCB input and the neutral to the neutral link. For double-pole MCBs, connect both phase and neutral wires from the sub-meter output to the MCB input .
5. Neutral and Earth Links: The neutral link distributes neutral to all output loads, while the earth link connects the protective earth of the supply, sub-meter, and loads. The metallic body of the distribution box should also be bonded to the earth link for safety .
6. Testing and Configuration: After wiring, configure the sub-meter according to the manufacturer's instructions, including calibration and measurement settings. Test the installation by checking voltage, current, and meter readings to ensure accuracy .

Safety Considerations

• Always switch off the main supply before starting the installation.
• Use appropriately rated MCBs and RCCBs for the load.
• Ensure proper grounding to prevent electric shock.
• Follow color codes for wiring: typically red/black for live, blue for neutral, and green/yellow for earth. By following these steps, the sub-meter will accurately monitor electricity usage while maintaining safety and compliance with standard electrical practices.