Communication-capable Circuit Breakers
WL Circuit Breaker
External power consumption of a WL Circuit Breaker with CubicleBUS
WL Circuit Breakers with CubicleBUS are designed to provide internal and external communication when the main contacts are open. It is therefore necessary to connect an external power supply.
General information
The current sensing devices of WL Circuit Breakers consist of two components. The Rogowski coils deliver the current measuring values, and the energy converters provide the trip units with power. For breakers without an additional external supply, the trip units are
already activated and monitor the current at minimum values of 80A for Frame Size II, and 150A for Frame Size III.
The current from the sensors are sufficient to not only activate the protective functions of the ETU745 or ETU748 trip units, but also to activate the display, however, the
The display of the ETU776 only functions when an external CubicleBUS power supply has been connected. The protective functions are fully operational when primary current is flowing even though the display is not active.
If additional CubicleBUS components are applied on a WL Circuit Breaker, the breaker must be connected to an external UL Listed 24V DC class 2 power supply.
The CubicleBUS consists of four wires, two for the communications and two for the UL Listed 24V DC class 2 power supply. The CubicleBUS is connected to the external terminal X8.1 to X8.4.
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WL MODBUS Communication and Electronic Accessories • January 2005