... .ISO, ccc certifitate 3.State grid partner 4.20years experience low voltage switchgear Technical requirement Main circuit rated voltage 400V,690VRated ... ,C,PE,N3 phase 5 wire systemA,B,C,PE,N Regular service conditionsAmbient temperature:-5°C-- +40°C,daily average ... exceed 50%, a larger relative humidity is allowed at a low temperature (such as + 20°C to 90%),and temperature changes ...