Check for proper IP/NEMA ratings and material quality. Ensure safe placement: install in dry, accessible areas with good ventilation and at appropriate height (typically ~1. Practice good wiring: secure grounding, neat cable management, proper insulation, and correct wire gauge and. This document represents the minimum requirements and specifications for the installation of the electrical underground distribution systems fed from padmounted transformation, serving Secondary Service Accounts, to be transferred to Oncor Electric Delivery Company ownership. 1 This document is one of a suite of documents intended for designing and installing substations for adoption, and/or for use, by Scottish and Southern Electricity Networks (SSEN) Designers and Installers, covering the following situations. They shall provide sufficient volume to accommodate expected flows. Load. After preliminarily determining the type and specifications of the distribution box, the relevant technical parameters and usage requirements should be provided to the manufacturer for final confirmation.