... restrictions on geographical location and the outdoor environment and mang other advantages. It consists of the box, power supply, temperature ... : a. 1: residential area, less than 55dB b. 2: other regions, less than 76dB 8. Grounding protection: the protection of ... metal component to be insulated from each other, the insulation resistance of not less than 500MΩ,Each connected by not less than 4mm2 ...