AFCI's Tripping

[etelectrician]

I have been asked to check a fairly new house (1 yr old) because arc fault breakers keep tripping. I talked to the home owner via phone today, and he said that when one trips downstairs that the ones for the two upstairs bedrooms trips. He said it seems to do it more when it rains (?). He also said that the outlets upstairs do not have any load on them, as they are in his two small childrens bedrooms. Any ideas where to start?
Thanks.

 

[Dennis Alwon]

I bet the upstairs have a load on it somewhere. Are the lights part of the circuit? I would look for something that gets turn on/off periodically.

 

[etelectrician]

Not really sure if lights are on that or not, homeowner did not say. What do make of all three AFCI's tripping when one will trip and the issue with the rain?

 

[Dennis Alwon]

Not really sure if lights are on that or not, homeowner did not say. What do make of all three AFCI's tripping when one will trip and the issue with the rain?

Well if the rain is truely causing a problem then there must be something outside attached to those circuits. I am a bit skeptical about info obtained from a homeowner. You are going to have to dig in. Not sure why all three are tripping unless someone ran a MWBC and landed these on sp afci. It could be they got the neutrals mixed in the panel. Start there and work your way out.

 

[etelectrician]

Good Call. You may have hit on something with the neutrals being switched. I have ran into that before with GFCI's. The homeowner is an electrician himself and trained me when I first got into electrical. I doing this as a home warrenty follow up for the contractor that built house. Original electrician on house pasted away.

 

[gar]

091201-2138 EST

Is the rain accompanied by lightning?

.

 

[kbsparky]

Surge power strips, such as those commonly used with electronics and computers. Shunting surges to ground can cause the GFPE circuitry to activate the breaker to trip.

 

[etelectrician]

Gar,
No, not necessarilly.
Thanks

 

[gar]

091219-0844 EST

etelectrician:

My initial reaction is to be looking for some transient trigger source on the input side of all the AFCIs. It is less likely that arcing or a transient on the load side of one AFCI would trigger the other AFCIs. This is just a general concept. I have not experimented with any AFCIs.

I am implying that an AFCI might be sensitive to a voltage transient that has nothing to do with its monitoring of current signatures.

.

 

[brian john]

Do you have a megger?

Verify they are properly installed.
Check for loads on the circuits
Check for recalls from the manufacture.
Megger the circuits.