This document provides specifications for various distribution boxes including dimensions, mounting sizes, and number of ways. No matter how ha sh the environment is, there is always a proper enclosure for your needs. Thanks to protection ratings and high quality ble (from 65 x 65 mm up to 361 x 254 mm) plus 3 different cover hei xes are available. required. Isolator Base should withstand the breaking capacity of 80 kA. To extinguish the arc immediately in iso ators, in each phase arc-chutes with minimum 12 strips ype. The outgoing line from the low-voltage end of the transformer is 0. Let's make an example for clarity: A newly constructed residential area introduces a 10kV power line to a substation.