Secondary distribution box with electricity meter

A secondary distribution box itself does not typically contain an electricity meter; it distributes power to circuits that may each have individual meters.Function of a Secondary Distribution Box

A secondary distribution box, also called a sub-distribution board (SDB), is designed to split incoming electrical power from the main supply into multiple secondary circuits. It usually contains fuses, circuit breakers, and protective devices to ensure safe operation of each circuit within a building or facility . Its primary role is distribution and protection, not measurement of electricity consumption.

Relationship with Electricity Meters

While the secondary distribution box distributes electricity, electricity meters are installed separately to measure consumption for individual circuits or properties. In multi-unit buildings, the main supply may have a primary meter, and each unit can have its own meter connected downstream of the secondary distribution box . The secondary distribution box may hold the fuses or breakers that connect to these individual meters, but it does not itself record energy usage .

Practical Example

In a residential or commercial building:

• The main meter measures total electricity entering the building.
• The secondary distribution box divides this power into circuits for apartments, offices, or equipment.
• Individual meters for each unit or circuit are connected after the secondary distribution box to track consumption for billing purposes .

Summary

A secondary distribution box is a power distribution and protection device, not a metering device. It works in conjunction with electricity meters, which are installed separately to measure energy usage for individual circuits or properties. This setup ensures both safety and accurate billing in multi-circuit or multi-unit electrical systems .