Each DISTRIBUTION BOX and controller must be grounded. 26 mm 2 (10 AWG) ground wire must be used, and in all other markets a 6 mm 2 must be used. • Good system grounding provides the path for normal load and fault currents while maintaining load and controls temporary overvoltage. Grounding is necessary to assure correct operation of electrical devices, to assure safety. Think of it this way: That distribution box in your facility? It's not just a metal container – it's the. Abstract: Discussed in this recommended practice is the system grounding of industrial and commercial power systems. It can also be an aid to all engineers responsible for the. In resonant-grounded or compensated distribution networks the system is grounded through a variable impedance reactor connected to the power transformer secondary neutral or the neutral of a grounding bank.