This enclosure box is rated as a Type 3R/5/12 with removable blank end walls. Whether you are installing outlets, switches, lighting fixtures, or junction connections, box size directly affects wire fill capacity, device fit, and installation quality. Learn how to. NQ and NF Panelboards applications include commercial buildings, industrial buildings, data centers, stadiums, and offices. The guide rail can be adjusted in both. This guide explains electrical box dimensions, standard sizes, depth options, and volume calculations to help you select the correct enclosure.