Can an AFCI trip due to a loose neutral when hots are disconnected?
Asked by CuriousCraftsman92
Hey DIY folks! I'm dealing with a perplexing situation with my AFCI. I had a circuit that was intermittently tripping, so I decided to replace the AFCI. After that, I disconnected all the hot wires at each junction box, yet the breaker still trips occasionally. In the end, I called in an electrician, who checked things out and discovered a loose neutral in a light fixture. It's baffling! How can an AFCI detect a loose neutral if all the hot wires are disconnected? What am I not understanding about its functionality?
Answers
AFCIs are a bit tricky since they detect arcing, which isn’t as straightforward as GFCIs that just measure current. Even when the hot is disconnected, AFCIs can still sense issues. They look for high-frequency signals (like 100kHz) that might indicate arcing from induced currents. So, even if your hot is off, there might still be some backfeed that can trigger the AFCI! Crazy, right?
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If you only disconnected the hot and left the breaker on, the breaker could still be getting power and might detect arcs through the neutral. Just because the hots are disconnected doesn’t mean it's completely out of the picture!
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I’m not sure if an AFCI would trip without a hot. Typically, they monitor both hot and neutral for arcs. If there's no hot, it's tough for it to detect anything substantial. But who knows, it could still pick up on some induced voltage, causing that nuisance tripping you’re experiencing!
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Good question! It’s probably not likely for an AFCI to trip solely due to an open neutral if the hot wire is disconnected. It relies on current from the hot to detect arcs. However, they can be sensitive to noise or induced currents, which might cause false trips. Your loose neutral might be just a part of the problem, not the whole story.
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That sounds confusing for sure! But it might be that there’s enough induced voltage on the neutral for the AFCI to pick up on. They’re super sensitive and can catch tiny arcs that could happen at a bad connection. Sometimes these issues can be sneaky!
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CuriousCraftsman92: That definitely explains some things! I always assumed it would only work with the hots connected.