3) The distribution boxes shall be duly wired with suitable size of PVC insulated single core copper cable or equivalent section copper / aluminum flat. 4) Terminal connectors for the earth connections to be provided in the box. The wire cross-section of the main circuit is marked in accordance with the. A distribution box is a low-voltage electrical enclosure that receives incoming power and distributes it safely to multiple outgoing circuits through protective and switching devices such as MCBs, RCDs, RCBOs, fuses, isolators, busbars, neutral bars, earth bars, and surge protective devices. The. Phase rotation 3-phase inverter/charger systems This chapter covers AC electricity generation, distribution, cable sizing and the AC wiring of inverter/charger systems. This list includes substantive updates only and is not intended to reflect all changes.