If your tester suddenly stops – perhaps a clear Relay Error, an ambiguous Err 17 or a dreaded Hardware Error message — there’s a good chance a relay has given up. So, what are these pesky relays and why can they cause so much trouble?
Relays are the electromechanical switches in your tester - and your tester is packed full of them! They control everything from applying test voltages, bridging conductors during insulation tests to checking loads before tests. And they do a lot of switching — some testers have a dozen or more, clicking away constantly during every test. Over time, all that mechanical movement adds up. Like anything with moving parts, they wear out.
Then there’s inrush current — that big spike when certain appliances start up. In some instances, that surge can weld the contacts together, leaving it permanently stuck.
So no, it’s not bad luck, poor design, or cheap components — relays are just doing a tough job, thousands of times a week. And sooner or later, one’s going to say “I’m out.”
