Wiring requirements of distribution box Upper incoming line, lower outgoing line, main circuit on the left, control circuit on the right, horizontal and vertical. The exposed laying can take the sheath line, or through the pipe and trunking. Whether in a home or an industrial facility, this box keeps your electrical setup organized, functional, and efficient. However, the key to. Designing a power distribution board is not just about placing components inside a metal box. The IEC Standard for Power Distribution Board Design and Layout serves as the global. Distribution Board aslo know as “Panel Board”, “Switch & Fuse Board” or “Consumer Unit” is a box installed in the building containing on protective devices, such as circuit breaker, fuses, isolator, switches, RCDs and MCBs etc.