This document provides specifications for various distribution boxes including dimensions, mounting sizes, and number of ways. Check out this quick guide: Think about how many devices you need, where you will install the box, and the environment. Actual units use PNP status indicator, NPN status indicator, or neither. Dimensions are shown in mm (in. The body of the boxes shall have sufficient re- enforcement with suitable size of channels keeping a provision for fixin andle conforming to general. le pole Isolator (Switch Disconnector), conforming to relevant latest I. The supplier shall submit Type Test Repor of the Isolator for approval of Employer before commencement of supply. The Switch disconnector to e provided.