AFCI tripping

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pbeasley

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Orange County, CA (for now)
I have been able to get by so far without having problems with AFCI's, but no more. This situation came up over the weekend during trim out and I'm not clear on why this would be the case.

Residence with 200A main panel, 100A sub panel on 2nd floor. Both panels are SqD Homeline. A/C compressors fed from Main panel. There are two 20amp AFCI's (not the combination type) in the sub panel that are tripping, and it appears they trip when the A/C kicks in.

Does it make sense for something up-stream of the breaker to cause this tripping? I am guessing it is more likely a vibration problem but open to other suggestions. No, I don't have a megger, though I may have one soon :smile: ....
 
Are they the only arc faults in the panel? I have seen some strange things with GFCI like that so I guess it is possible. I'll assume you changed the arc faults out.
 
You may want to invest in an Afrc-Fault tester. How often does it trip? Can you leave the a/c off for an extended period of time to see if the breakers still trip on their normal interval? I just did a service call a couple of weeks ago for arc-fault tripping and it wound up being neutral and ground got to close. (BTW, I hate tracking down for an hour what you know will be a 2- minute fix :mad: , but you gotta find it to fix it :roll: ) Anyway, the breaker started tripping periodically until it got to the point it was constant and they called me. I would chalk that one up to movement of the conductor over time because of vibrations throughout the house. Whoever installed the receptacle did not do so properly (yes, it was a house we wired, and it could of been me, but I will blame it on the helper who is no longer with us :) ) and the conductors just worked their way to fault point with every nearby thump of everday life.
 
Dennis Alwon said:
Are they the only arc faults in the panel? I have seen some strange things with GFCI like that so I guess it is possible. I'll assume you changed the arc faults out.
Click to expand...

Tried changing out with another breaker form the same batch, Also just bought a combination type just in case. There are a total of 8 AFCI's in this panel, only these 2 are having problems (at least so far) The rest are only 15amp.
 
360Youth said:
You may want to invest in an Afrc-Fault tester. How often does it trip? Can you leave the a/c off for an extended period of time to see if the breakers still trip on their normal interval? I just did a service call a couple of weeks ago for arc-fault tripping and it wound up being neutral and ground got to close. (BTW, I hate tracking down for an hour what you know will be a 2- minute fix :mad: , but you gotta find it to fix it :roll: ) Anyway, the breaker started tripping periodically until it got to the point it was constant and they called me. I would chalk that one up to movement of the conductor over time because of vibrations throughout the house. Whoever installed the receptacle did not do so properly (yes, it was a house we wired, and it could of been me, but I will blame it on the helper who is no longer with us :) ) and the conductors just worked their way to fault point with every nearby thump of everday life.
Click to expand...
Thanks for sharing, always good to know I'm not the only one :). Have been thinking about a new tester, but was thinking megger. What Arc-Fault tester do you recommend? I'll double check the neutral/ground thing as well.
 
pbeasley said:
Thanks for sharing, always good to know I'm not the only one :). Have been thinking about a new tester, but was thinking megger. What Arc-Fault tester do you recommend? I'll double check the neutral/ground thing as well.
Click to expand...

To be honest I have not looked at much beyond price and the price is still steep enough that I have not seriously considered one for as little as I find need. I do not know what kind of relevant information the tester can even give in these circumstances. But anytime is a good time to look into a new tool.:D
 
electricmanscott said:
Could you direct me to this tester? :-?
Click to expand...

If you are refering to my sorry spelling, then I can't help you.:D

If you are talking about an actual tester, try starting here. As I mentioned earlier, I don't know if there are any diagnostics on a tester that would help in these circumstances, but it may worth looking into.
 
The AFCI 'testers' are a worthless investment, in my opinion. The one's I know about are:
  • Certain Ideal SureTest models
  • Amprobe BT-AFT1 arc fault tester
  • Etcon AF120 arc-fault tripper and receptacle tester
  • Fox Meter Inc 'Arc Smart' AS-1000
For my money, you'll get all your AFCI problems rooted out with a megger.
 
pbeasley said:
Does it make sense for something up-stream of the breaker to cause this tripping?
Click to expand...

I had a 20A 120V AFCI downstream of an arcing 200A main breaker trip. I believe even low quality power at the meter could trip one.

And don't forget how a company designs their AFCI is up to them, just so it meets UL criteria. They may very well react differently due to the methods employed.

Also, all AFCI's have 30 ma. GFCI's built in. If vibration causes the neutral to touch ground...it's tripped.
 
pbeasley said:
I have been able to get by so far without having problems with AFCI's, but no more. This situation came up over the weekend during trim out and I'm not clear on why this would be the case.

Residence with 200A main panel, 100A sub panel on 2nd floor. Both panels are SqD Homeline. A/C compressors fed from Main panel. There are two 20amp AFCI's (not the combination type) in the sub panel that are tripping, and it appears they trip when the A/C kicks in.

Does it make sense for something up-stream of the breaker to cause this tripping? I am guessing it is more likely a vibration problem but open to other suggestions. No, I don't have a megger, though I may have one soon :smile: ....
Click to expand...

Just thought I'd let everyone know it looks like this was a NM connector that was over tightened. Think I'll be watching fleabay for a meggers now.
 
mdshunk said:
The AFCI 'testers' are a worthless investment, in my opinion. The one's I know about are:...

For my money, you'll get all your AFCI problems rooted out with a megger.
Click to expand...
It there really an arc at all ?

Could you explain this more, from what I'm reading here its not so much an Arc as it is an induced and electrical EMS from the neutral to ground? (did I get that right?)

Now for example, If you bust the receptacle out to megger the circuit, then you could well be clearing the closeness of the circuits and might read clear and once remounted one recreates the problems.
 
cadpoint said:
Now for example, If you bust the receptacle out to megger the circuit, then you could well be clearing the closeness of the circuits and might read clear and once remounted one recreates the problems.
Click to expand...
Which is why megger checking, for the purposes of finding the cause of AFCI and GFCI breaker tripping, needs to start at the connection in the panel, and divide and conquer from there.
 
pbeasley said:
Just thought I'd let everyone know it looks like this was a NM connector that was over tightened. Think I'll be watching fleabay for a meggers now.
Click to expand...

Let me guess...someone used an electric screwdriver to tighten the NM connector. Good case to use the hit-lok nm connectors (cheaper too).

Also, I consider a romex staples' only function in life is to hold the nm in the wall long enough for the rocker to close it up. That extra wack with the hammer can cost you big time. If an inexperienced helper is on the job the cushioned staples may be worth it.

Glad you found it. How long did it take?
 
ohm said:
Let me guess...someone used an electric screwdriver to tighten the NM connector. Good case to use the hit-lok nm connectors (cheaper too).

Also, I consider a romex staples' only function in life is to hold the nm in the wall long enough for the rocker to close it up. That extra wack with the hammer can cost you big time. If an inexperienced helper is on the job the cushioned staples may be worth it.

Glad you found it. How long did it take?
Click to expand...

2 of us about 3 hours to find and fix. it was on the bottom of 4 gang box. sadly enough, ran out of plastic connectors during the install and finished off with some left over screw type. clearly a mistake.
we were able to keep the patch work to a minimum.. on a two gang it would have just been a larger cover plate.
 
pbeasley said:
Just thought I'd let everyone know it looks like this was a NM connector that was over tightened. Think I'll be watching fleabay for a meggers now.
Click to expand...
Do you mean a twist connector that was overtightened but realy loose?:-?
 
Bill,

I think he's saying screw tightened diecast NM cable clamp. Consider:
pbeasley said:
ran out of plastic connectors during the install and finished off with some left over screw type. clearly a mistake.
Click to expand...
 
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pbeasley said:
2 of us about 3 hours to find and fix. it was on the bottom of 4 gang box. sadly enough, ran out of plastic connectors during the install and finished off with some left over screw type. clearly a mistake.
we were able to keep the patch work to a minimum.. on a two gang it would have just been a larger cover plate.
Click to expand...

Rework hours are longer than new work hours. But, that's water under the bridge now and nobody said education was cheap.
 
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