DZ20 series plastic case circuit breaker (hereinafter referred to as circuit breaker), its rated insulation voltage is 660V (225A frame and below 800V), AC 50Hz, rated working voltage 380V (225A frame and below 400V) and below, The rated current is from 32A to 1250A. Generally used as power distribution, 400A shell frame and below can also be used as a protection motor. Under normal conditions, the circuit breaker can be used as an infrequent turn of the line and an infrequent start of the motor. Circuit breakers for distribution, used to distribute electrical energy in distribution networks, and can be used as overload and short circuit protection for line and power equipment. The circuit breaker for protecting the motor is used as a squirrel-cage type motor for starting and running breaks in the power distribution network and as an overload and short circuit protection for the motor. In this series, the three-pole products with rated currents from 100A to 630A also have a transparent cover. The cover is made of a new high-temperature resistant and high-strength polycarbonate material, which can intuitively judge the on-off state of the contacts. It is used in temporary power stations on construction sites. Meet the standard: GB/T 14048.2, IEC 60947-2.