Loose or damaged connections cause many faults in low voltage distribution boxes. Here is how you can do it: Use a calibrated torque-wrench to make sure connections are tight. Poor. An MCB Distribution Box (DB) is the central point of power distribution in any electrical installation—whether residential, commercial, or industrial. It houses Miniature Circuit Breakers (MCBs) that protect electrical circuits from overloads and short circuits. These faults can interrupt power, damage equipment, and increase downtime.