* Altitude belows 2000m;
* Circuit breaker may be used between -25℃ and + 70℃. For temperatures higher than 40℃(65℃ for circuit breakers used to protect motor feeders), devices must be derated;
* It can withstand the impact from humid air, salt spray, oil mist and mold;
* It should be installed in places with no danger of explosion, no conductive dust, and no substance enough to corrode metal or damage the insulation.
* In places with no rain and snow erosion;
* Pollution degree 3;
* Installation category III.