According to the "Code for Acceptance of Construction Quality of Building Electrical Engineering" GB50303-2002, the vertical distance between the bottom surface of the fixed stainless steel enclosure ip67 and the ground should be greater than 1. The bottom surface. Distribution box and switch box should not exceed 30 meters. Generally, distribution boxes can be divided into three levels of secondary protection, that is, three levels of distribution boxes: general. These guidelines provide you with information on the installation of electricity mains, services, streetlamps, and other parts of our electricity networks. The guidelines also cover the safety aspects of GTC completing works onsite and specify your responsibilities in the delivery of the. This document is provided for information purposes only. If no information classification has been included, this document must be treated as 'Public' and must not be disclosed other than with the consent of nbn co.