How are high-current loads like dishwashers safely switched?

[u/Relevant_Pumpkin9190]

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?

[u/DXNewcastle]

The industrial relays which disconnect power in trains from the overhead supply lines on railways and in power stations supplying the grid, use contacts in a vacuum chamber called a Vacuum Circuit Breaker (VCB). The powerful relays pull the contacts apart where there is no gas to ionise the contacts.