On the secondary side, switched-mode power supplies provide DC voltage to control circuit loads (e.g., controllers, operating panels, displays and auxiliary relays). These control circuits also call for wiring protection and if the load has no protective unit of its own, device protection as well. Furthermore, the Machinery Directive (EN 60204) requires hazardous ground faults in control circuits to be detected and switched off within five seconds.
The overcurrent protection in primary switched-mode power supplies reacts very quickly to overcurrents on the output side. Selective protection of individual current paths in the secondary circuit via fuses or conventional circuit breakers is often ineffective if the power supply cannot deliver a brief overcurrent.
Electronic Circuit Breakers
WAGO’s ECBs offer greater safety for protecting your system. Thanks to their communication capabilities, they also provide data about the current status of the channel and the connected loads.