Electrical – AFCI Breaker tripping

Some surge protectors work by "redirecting" surges to the equipment ground, which is pretty much the definition of a ground fault. In this case, it's definitely possible that surge suppressors could be tripping GFCI receptacles/breakers (given a large enough surge).

As for the AFCIs... When electrical contacts separate, they often create an arc between the contacts. This arc spans the gap until the contacts are too far apart, and the arc can no longer be sustained. It's possible (in theory) that the GFCI tripping could create a large enough arc, for long enough to cause the AFCI to trip. It's not likely that a properly functioning GFCI would do this, but if the GFCI was old and worn it could be opening the contacts slow enough that a detectable arc is being produced.

Determining if the GFCI tripping is causing the AFCI to trip, is a simple test. Simply press the test button on the GFCI. If the AFCI trips, you'll have figured out half the problem. If the ACFI does not trip, you could repeat the test using a receptacle tester with a GFCI test function.

If it's determined that the GFCI is causing the AFCI breaker to trip, replacing the GFCI receptacle may resolve that part of the issue.

Figuring out if the surge suppressor is tripping the GFCI, is a more difficult proposition. It will likely require you to monitor the supply voltage over some time, to identify and document possible surges.

From the comments posted above I understand....

You say that you measure a hot to neutral short at the electrical box for one particular circuit. On the other hand you say that no short is measured across hot to neutral at the outlet boxes.

This can mean one of two things.

(One) Something severed one or both of the wires between the outlet string and the breaker box and in the process caused the two wires to become simultaneously shorted on the breaker box side of the break.

(Two) The shorted pair from the breaker box is feeding a different circuit than you think it is.

For the first case you should really think about what has changed in your building between now and when the outlets used to still function properly. In most cases it is unlikely that wires spontaneously break and short together without there being some interposing disturbance of the wiring. This can give a clue of where to start looking. Did something get nailed or screwed to a wall someplace? Did a window get replaced?

I can think of one case where a wire break/short could happen and that is if there was a loose or high resistance connection that over time caused so much heat to be produced wherein the wires melted apart and also shorted due to the insulation burning off. This type of failure is most likely going to happen inside an electrical box itself where connections exist.

For the second case the obvious thing is that you need to guide your attention to the correct circuit. Note that I have seen many cases where the breaker function labels in the breaker box are incorrect. So double check the circuit carefully.

To aid in either case there is a simple technique where you can run a known good conductor from the destination point back over to the breaker box. Just lay it along the floor / ground. Then wire clip one end of it a wire in question at the destination and use the other end of the wire with your multimeter. This effectively makes one of the test leads of your multimeter long enough that you can look for continuity or opens between breaker box and destination without having to buy other types of test gear. This kind of testing should obviously only be done when all the power is turned off. Use a flash light or battery powered lamp if it gets too dark to see.

One other thing to think about....if not already being done....is that when testing for problems like this it is generally necessary to remove all connections from each wire run and test against wire ends that are free ended.