AFCI breaker trips when turn on shower

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Well-Known Member
Feb 16, 2015
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Good morning! So, it isn't the actual breaker. The problem occured after making the switch. So, seems clear it is in the circuit. But, to eliminate further, could this be related to the ground, which is only connected to the house plumbing and there is no ground rod ? Thank you in advance for your help!
Try temporarily removing the ground to see if it makes a difference. If you have a meter you might also check for ground current.
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Established Member
Aug 28, 2016
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Not having a ground rod should not make a difference in this case.

You say your ground to the panel is to your incoming water line. I would assume and please confirm that the ground connection to your panel is as close as possible to where the water line comes into your home. Also that the water line is city water which would mean copper line more than likely. If you have only well water into home please let us know - might be another separate issue.

Let's take care of this issue - breaker tripping - first please.

What you need to do is let us know if this breaker is a dual AFCI/GFCI or just a AFCI breaker.
If this breaker is only AFCI then the breaker is sensing that there may be an arcing on the circuit somewhere either in parallel or in series (thus the term CAFCI - Combination Arch Fault Breaker).

If the breaker is a dual function AFCI/GFCI then it may be sensing a ground fault or an arc fault in the circuit. So the first thing you need to do is tell us what type of breaker it is.

Ground faults and Arc faults are two totally different types of faults.

Assuming it is only a CAFCI breaker then it is either sensing a arc fault in the circuit or there is an overload somewhere in the circuit. One more thing to try to eliminate the fact that it is an overload of some sort in the circuit and narrow this down a bit more.

Now move the circuit to a regular breaker. Take the neutral and hot off the AFCI breaker. Place the hot into the regular breaker and the neutral to the neutral bar (make note of which neutral wire you are moving so when it is time to put that neutral wire back onto the AFCI breaker it is easy to find). Now once the circuit is hooked up to a regular breaker if it trips it is more than likely an overload. If it does not trip it is a arch fault if the breaker is only an AFCI breaker - if the breaker is a dual function AFCI/GFCI then it can be either an arc or ground fault. Once you finish this test move the circuit back to the original breaker. Take the circuit neutral wire and put it back into the AFCI breaker and the hot where that belongs in the breaker - to its original setup.

This will narrow down what is causing the breaker to trip. Once you do that the next step is to find the culprit causing the trip. Step by step - process of elimination.