Installation conditions and methods of power cabinets

Installation conditions
(1) The installation height shall not exceed 1,000 meters above sea level.
(2) The ambient medium temperature shall not exceed +40℃ and shall not be lower than -20℃.
(3) The relative humidity of the air shall not exceed 85%.
(4) Places without conductive dust and gases that can corrode metals and damage insulation;
(5) Places without explosion hazards;
(6) Places without severe vibration and jolting, and with a vertical inclination not exceeding 5°.
(7) After being treated in accordance with the requirements of the humid and tropical zone, the power box can be applied in areas where the relative humidity of the air does not exceed 95%, and where condensation and mold exist.

Installation method
Usually, a base is made of 10# channel steel, which is welded to the steel plate pre-embedded in the foundation (such as 100*100*6). Then, the power cabinet is fixed to the base with bolts or welding, or it can be directly installed on the bolts pre-embedded in the foundation. There is a standard installation drawing set available.

Repeated grounding
Repeated grounding should be installed in the following situations:
(1) The terminals of overhead line trunk lines and branch lines, every 1km along the line, and where the length of branch lines exceeds 200 meters;
(2) The first distribution device where the line is introduced into the workshop and large buildings (the entrance to the household);
(3) When using metal conduits for wiring, the metal conduits should be repeatedly grounded after being connected to the protective neutral wire. When using plastic pipes for wiring, a separate protective neutral wire should be laid and repeatedly grounded.

The function of repeated grounding:
(1) Reduce the risk of electric shock on the zero connection equipment when the PE line or PEN line is accidentally disconnected or has poor contact.
(2) Reduce the "drift" of the load neutral point when the PEN line breaks.
(3) Further reduce the ground voltage of the unexpectedly energized equipment during the duration of the fault.
(4) Shorten the duration of leakage faults.
(5) Improve the lightning protection performance of overhead lines.