The power supply needs to be installed in the aeration-dry indoor area, and keep away from the noxious gas such as acid and alkali. Because the noxious gas may corrode the electrical elements. It better to have doors in front and behind the power supply device and keep a distance about 800mm with the wall or other facility. The surrounding temperature should among the －10℃ to 45℃. And the relative humidity should be less than 90%.