... grid partner 4.20years experience medium voltage switchgear Technical requirement Main circuit rated voltage 400V,690VRated frequency 50HzRated insulation voltage 690V(1000V)Rated currenthorizontal ... voltageAC220V,400VDC110V,220Vpower frequency testing transformer(V/5s)25001760levels of protection IP30,IP40generatrix3 phase 4 wire systemA,B,C,PE,N3 ...