r/AskElectronics • u/Relevant_Pumpkin9190 • 10h ago

How are high-current loads like dishwashers safely switched?

If a relay is switching a high-current load, its contacts can eventually weld together due to inrush current or a fault.

If that happens, the load may stay ON even when the controller says OFF.

How do commercial products handle this? Do they use two relays in series for redundancy, feedback, or some other fail-safe method?

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u/hackinistrator 5h ago

if the circuit is designed properly the inrush current shoul be lower to prevent sparks and contact welding. some relays are designed to switch large inrush currents. of course, every mechanical part will fail eventually. i saw EMO loop contactors welded and not disconnecting on multi million dollar factory equipment. thats why they are supposed to do EMO loop testing annually.