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I just powered up the (dual function, 20A Siemens) circuit for my new laundry room, which is on a new subpanel. The circuit tests fine with my trusty 3-prong, 3-light tester. But whenever I plug anything else into it, the breaker trips. What could be the problem?

nobody
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5000fingers
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1 Answers1

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This sounds remarkably familiar.

Is the neutral wire correctly connected TO THE BREAKER? Insta-trip on device plug-in is very common with GFCI or GFCI/AFCI (and many but not all AFCI-only) breakers where the neutral is connected to the neutral bar, rather than the neutral connected to the (correct) breaker and the breaker connected to the neutral bar.

It could also be from an incorrect connection (or short) between neutral and ground in the wiring, which the "trusty 3-light tester" can't detect. The tester does not draw enough current to trip the GFCI circuit protection while just running its lights.

Ecnerwal
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