Earth leakage circuit breaker

The Terasaki ZS earth leakage moulded case circuit breaker (MCCB) offers machine or personnel protection within a standard 125 A, 160/250 A MCCB frame size. The MCCB maintains the functionality of a standard thermal-magnetic overload/short-circuit protection device.

Protection against electric shock hazard can be provided by circuit breakers incorporating residual current protection. Until now, MCCBs incorporating an RCD in Australia and New Zealand have been a combination type, where the circuit breaker is mechanically and electrically coupled to a residual current block. These add-on residual current blocks increased the overall dimension of the device as well as the overall power consumption due to the additional load, sometimes requiring a derating of the host circuit breaker.

As an integrated unit, however, the ZS MCCB enables a switchboard builder to use a switchboard, panelboard or chassis assembly designed for standard MCCB dimensions and mounting and still provide the residual current safety features in an integrated package, resulting in no increase in overall dimension or power consumption.

It is also simple to upgrade from a standard MCCB to an integral RCD/MCCB as the dimensions and mountings are the same.