A distribution board provides which of the following protections for branch circuits?

• A. Step-up transformer
• B. Contactor
• C. Providing isolation and protection to branch circuits
• D. Sensing power factor

Answer: (C)

Distributing power to branch circuits safely hinges on giving each circuit both a way to be disconnected for maintenance and a means to stop fault current. A distribution board is designed to house the protective devices—fuses or circuit breakers—and provide a main switch or individual switches so any branch circuit can be isolated from the supply and the current can be interrupted if something faults. This combination of isolation and overcurrent protection keeps wiring and devices safe from damage and reduces fire risk.

Other functions listed aren’t the board’s primary role. A step-up transformer changes voltage levels, which isn’t the job of a distribution board. A contactor is a control switching device used to start or stop loads under control signals, not the protective and isolating function of the board. Sensing power factor is something done by metering or correction equipment, not the core purpose of the distribution board. So, the description that best matches the board’s purpose is providing isolation and protection to branch circuits.