1 General DNH1(HR17) series fuse type isolating switch is a new type isolating switch with rated insulating voltage AC 800V, rated operating voltage 690V,400V , rated frequency 50Hz,and rated current 160A-630A,. It is mainly used as power switch, isolating switch and emergency switch with the functions of protecting circuit, however, it can not be used to directly close/break a single motor. This product is in conformity with the Standards of GB14048.3-2002 and IEC947-3(2001). 2 Construction Characteristic The sealed structure of this type isolating switch is three poles whole insulated. The whole enclosure is made of high strength fire-resistance materials with function of high insulating protection. The operate handle upon the cover is safe to use and convenient to operate. The transparent panel on the switch cover can be used to examine the working condition. And the cover is convenient to take off and the fuse is simple for replace. While the isolating switch is in the breaking, a clear fracture will appeared. The contact system of switch is advanced designed. When the switch breaks with load, the current will automatic transferred to the arcing corner, and while the switch compounded with excellent arcing chamber, it can be guaranteed the reliable break, few ablate on contact side, stable work condition. This structure of switch can be divided into to two types, one is fixed type, and another is hanging type. When the customers selected hanging type, the power supply will directly install incoming terminal via the base of switch according with the standard of landscape orientation. When the customers selected fixed type, the incoming terminal can connect with bus bar, and can be directly connected to cable while it is collocating with specific terminals. The parts of the switch adopt plug type, thus, the switch is convenient to maintain and repair. When a frame or molded type case circuit breaker has installed on the switch load terminals, this switch can be used as an isolating switch when it replace fuse to isolating knife. 3 Main Technical Parameter 3.1Rated insulating voltage:AC 800V 3.2 Rated operating current:AC 690V AC 400V 3.3 Rated heating current:160A, 250A, 400A , 630A