Crazy AFCI

[Dennis Alwon]

I started this thread so as not to take over little bill's thread on the crazy gfci.

First let me state that this was not my job but rather another ec's job. He has been dealing with this afci problem for month's and has done everything in his powers to solve the problem. I personally believe it may be a power quality issue.

So he had trouble with an afci tripping intermittently. Supposedly he went thru the circuit and found nothing. Similar to Bill's gfci it would work fine for days and last time it worked for most of the summer. Started again last week-- he assures me there is nothing plugged in that is causing the issue.

He went there last week an witnessed first hand that 3 afci's would trip when the home owner turned on the oven. Apparently she has never used this oven in the months that she has been there. The electrician reset the breakers and turned on the oven and pop all three afci's would trip. Poltergeist again I guess. I told him to get the power company to put a recording meter on the line side and see what is going on.

 

[starbolin]

I started this thread so as not to take over little bill's thread on the crazy gfci.

First let me state that this was not my job but rather another ec's job. He has been dealing with this afci problem for month's and has done everything in his powers to solve the problem. I personally believe it may be a power quality issue.

So he had trouble with an afci tripping intermittently. Supposedly he went thru the circuit and found nothing. Similar to Bill's gfci it would work fine for days and last time it worked for most of the summer. Started again last week-- he assures me there is nothing plugged in that is causing the issue.

He went there last week an witnessed first hand that 3 afci's would trip when the home owner turned on the oven. Apparently she has never used this oven in the months that she has been there. The electrician reset the breakers and turned on the oven and pop all three afci's would trip. Poltergeist again I guess. I told him to get the power company to put a recording meter on the line side and see what is going on.

AFCIs are a different matter as they will trip if there is a series fault on the line side also.

 

[Dennis Alwon]

AFCIs are a different matter as they will trip if there is a series fault on the line side also.

Please explain how an afci trips from a line side fault. If that were the case every afci in the panel woud trip every time another circuit trips-- that is not usually the case

 

[GoldDigger]

Perhaps clearer to say that the AFCI can trip from a line side fault that is in series with the breaker. That is on the main or the panel feeder.
To a much lesser extent it might trip on a series or parallel fault that is in a circuit parallel to the breaker-protected circuit.

 

[Dennis Alwon]

Perhaps clearer to say that the AFCI can trip from a line side fault that is in series with the breaker. That is on the main or the panel feeder.
To a much lesser extent it might trip on a series or parallel fault that is in a circuit parallel to the breaker-protected circuit.

So any thoughts on how an 240v oven can trip 3 afci's whenever it is turned on? Am I crazy about a power issue? I remember that Sq.D had issue in, Denver, I believe, with afci and they found out it was a power quality issue from the power company.

 

[GoldDigger]

Well, the only sort of power issue that I can envision that would be correlated with the oven being turned on would be excessive voltage drop.
If the oven switch contacts are bouncing and arcing, then a high VD could cause a strong arc fault signature voltage to appear on the panel bus.
Replace the oven switch and thermostat?
Quick experiment:
Turn oven on and leave it on while resetting the breakers. That will tell you whether it is the oven drawing current or the switch closure that is tripping the AFCIs. Also see if they trip when the oven switch opens.
An RF noise filter (choke) or a snubbing capacitor across the oven switch may also be fixes if the switch itself is 100% OK.

 

[Dennis Alwon]

As I understand it the afci will not reset unless the oven is off. Honestly I hate these 2nd party threads because I can only go by what they tell me and we all know that is not always accurate. I know that at least one of those afci have been an issue periodically as I mentioned in the first post. I volunteered to go help him but I think he wants to solve it-- trouble is he always calls me back to pick my brain. At this point I have no ideas without checking things myself. The original issue may be a staple in the wire that occasionally causes problems.

 

[GoldDigger]

As I understand it the afci will not reset unless the oven is off. Honestly I hate these 2nd party threads because I can only go by what they tell me and we all know that is not always accurate. I know that at least one of those afci have been an issue periodically as I mentioned in the first post. I volunteered to go help him but I think he wants to solve it-- trouble is he always calls me back to pick my brain. At this point I have no ideas without checking things myself. The original issue may be a staple in the wire that occasionally causes problems.

Well, if the observation is correct, then that leaves switching transients out of the mix and leaves a constant arc signature from the oven when energized or some sort of odd ground fault related perhaps to a three wire installation of the oven and a metallic connection to another ground somewhere in the wiring.
As always, I would start by determining whether the breaker trip was caused by apparent AF or GF.

 

[John120/240]

As I understand it the afci will not reset unless the oven is off. Honestly I hate these 2nd party threads because I can only go by what they tell me and we all know that is not always accurate. I know that at least one of those afci have been an issue periodically as I mentioned in the first post. I volunteered to go help him but I think he wants to solve it-- trouble is he always calls me back to pick my brain. At this point I have no ideas without checking things myself. The original issue may be a staple in the wire that occasionally causes problems.

Would a TDR meter (Time Delay Reflectormeter) i think, pinpoint the location of the offending staple ? IDNK

 

[Dennis Alwon]

Well until he calls me and asks me for help I am not sure what will help. To be honest I have never run into a situation where I wasn't able to fix the problem with afci's. The ec apparently changed brands on the afci to no avail. He is going to ask the power company to put a recorder on the house and see if there are any anomalies.

 

[Dennis Alwon]

Would a TDR meter (Time Delay Reflectormeter) i think, pinpoint the location of the offending staple ? IDNK

I don't know either. I really don't have any high tech equipment except a gaussmeter. Basically I have never had to use anything other than a meter that did V, amps and R

 

[GoldDigger]

If it is an arc in the oven circuit, a thermal camera might help more than a TDR. A high resistance arc with no continuity at low voltage would probably not show up on a TDR.

 

[mbrooke]

I started this thread so as not to take over little bill's thread on the crazy gfci.

First let me state that this was not my job but rather another ec's job. He has been dealing with this afci problem for month's and has done everything in his powers to solve the problem. I personally believe it may be a power quality issue.

So he had trouble with an afci tripping intermittently. Supposedly he went thru the circuit and found nothing. Similar to Bill's gfci it would work fine for days and last time it worked for most of the summer. Started again last week-- he assures me there is nothing plugged in that is causing the issue.

He went there last week an witnessed first hand that 3 afci's would trip when the home owner turned on the oven. Apparently she has never used this oven in the months that she has been there. The electrician reset the breakers and turned on the oven and pop all three afci's would trip. Poltergeist again I guess. I told him to get the power company to put a recording meter on the line side and see what is going on.

Wild guess, but is the oven induction? Id check the connections to the oven just to make sure nothing is arcing. Yup, I know the oven isn't AFCI protected, but I have heard of arcing on other circuits tripping them.

 

[ActionDave]

Well until he calls me and asks me for help I am not sure what will help. To be honest I have never run into a situation where I wasn't able to fix the problem with afci's. The ec apparently changed brands on the afci to no avail. He is going to ask the power company to put a recorder on the house and see if there are any anomalies.

I have personally seen two casea afci breakers trip on circuits that had no wiring errors. GE and Sq D were the brands.

The trips in both cases were caused by power tools with a soft start feature. Different brands of tools, different kinds of tools, only thing they shared in common was the soft start. I'm sure they used electronics to do it. I'm sure it was not the brushes that caused the trip because any other tool, including my old Skill saw that will throw a giant blue arc around the armature, did not cause a trip and no other loads would cause a trip. I know it was not a problem with the tools because they functioned fine when plugged into a GFCI protected circuit.

I say all that to say that I have no trouble believing that the AFCI breaker is the problem and I'll bet it is probably something to do with the electronics in the oven.

 

[electricalist]

I love trouble shooting. So id have to first swap the afci breakers with one already in the panel. Paying attention to phase and distance from oven breaker. . If the next set of afci s trip. Id move the oven breaker to phase opposite from what it is now. If they still tripped id lean towards what circuits tripped. They are possibly stappled. To know I would have my own temp circuit or move the oven to the panel and temp wire it to breaker. Its not very realistic the others could trip now. If they do they have bigger problems than a arc

 

[edlee]

I had a problem a few years back where an electric dryer running would cause a new 15a120v AF breaker to trip in a subpanel remote from the panel that had the dryer circuit. There were several new AF circuits in the subpanel but only this one tripped. It seemed crazy to me.

I tried a few things that didn't work, and eventually opened up the dryer receptacle and tightened the connections, which were somewhat loose. The tripping stopped.

 

[Sierrasparky]

I had a problem a few years back where an electric dryer running would cause a new 15a120v AF breaker to trip in a subpanel remote from the panel that had the dryer circuit. There were several new AF circuits in the subpanel but only this one tripped. It seemed crazy to me.

I tried a few things that didn't work, and eventually opened up the dryer receptacle and tightened the connections, which were somewhat loose. The tripping stopped.

So are you saying that a Arc fault signature somewhere else in a electrical system can cause a AFCI to trip in an unrelated circiut?

WOW

 

[GoldDigger]

There are some protections to limit that. One is just sensitivity. Another is looking for a matching, correct polarity signature in both hot and neutral.
A third is the requirement for some signatures that there be a minimum (8A?) amount of current flowing through the breaker.

 

[Dennis Alwon]

There are some protections to limit that. One is just sensitivity. Another is looking for a matching, correct polarity signature in both hot and neutral.
A third is the requirement for some signatures that there be a minimum (8A?) amount of current flowing through the breaker.

I think 8A is high. Ge is about 4 amps I believe before it will read an arc. It is good info to know when trouble shooting. My guys were stymied trouble shooting a tripped afci on a second floor bedroom circuit. They said the fans worked fine until they turned the lights on but the fan had to be on high then it would trip. They were sure it was the lights. I knew it was the fans simply because it is the usual case. We change to a different generation afci and all was good.

 

[cowboyjwc]

If you're getting something back on the neutral, I wouldn't see why an AFCI wouldn't see that. Try disconnecting the neutral from the oven and then turn it on and see what happens.