In essence, a Distribution Box is the nerve center for your electrical system. Protect against overloads and short circuits. House critical safety devices like RCDs. A properly installed electrical distribution box is important for. Many modern distribution boxes include a life-saving device called an Earth Leakage Circuit Breaker (ELCB) or Residual Current Device (RCD). It detects tiny imbalances in current that could be flowing through a person (electric shock) and cuts power in a fraction of a second. Plastic Distribution Boxes: Constructed from materials like PVC or polycarbonate, these boxes are light and resist corrosion, making them suitable. Quick Facts/Did You Know?.