Be sure that the power distribution box has sufficient power provided to it. Long cable runs can result in a voltage drop, which can be solved by using a heavy gauge wire. The input phase L1, L2, or L3 voltage is above the high threshold. According to the electrical wiring, the switchgear, measuring instruments, protection appliances and auxiliary equipment are required to be assembled in closed or semi closed metal. Here are some solutions when a power distribution box fails: Safety First: Make sure you are safe. Do not touch live parts, turn off the corresponding power switch to avoid the risk of electric shock.