Are you sharing a neutral on the AFCI circuit? I don't think single-pole AFCIs can share a neutral.
AFCIs + other circuits
I can't figure this out. This is the work I did:
Installed a new subpanel.
Split an existing 15 amp circuit into two 15 amp circuits by running new 14/2 to midpoint in the circuit and completely removing the feeder from the previous location.
Added a completely new 20Amp circuit.
The two 15Amp circuits are bedroom circuits, so they are on AFCI breakers.
When the drywallers use their screw gun on the 20amp circuit, it stays on, but one of the 15 amp circuits trips. The same thing happened when I activated a light on the 20Amp circuit, but not every time.
Seriously, there is no point that these circuits even get close to each other; they leave the panel and go in opposite directions to different floors -so it's not as if there could somehow be a crossed neutral or something.
My helper thinks that the screw gun motor is somehow creating a voltage drop in the panel and that this is tripping the 15A breaker. I definitely do not know how that would effect a AFCI, especially on a separate circuit, but that seems ridiculous to me. Unless maybe the power co is giving me a bad neutral and some of the voltage is going out the ground? But why would that effect the AFCI different circuit if it didn't already have a load on it?
I tried a different AFCI just in case the one I had was "sensitive". It still happened. I used a regular breaker and of course it doesn't trip.
I have heard (or read) that adjoining breakers can trip an AFCI, but I kinda thought that wasn't likely and that there must be something else wrong. Could this really be true?
Any insights?
Thanks in advance,
Greg
Installed a new subpanel.
Split an existing 15 amp circuit into two 15 amp circuits by running new 14/2 to midpoint in the circuit and completely removing the feeder from the previous location.
Added a completely new 20Amp circuit.
The two 15Amp circuits are bedroom circuits, so they are on AFCI breakers.
When the drywallers use their screw gun on the 20amp circuit, it stays on, but one of the 15 amp circuits trips. The same thing happened when I activated a light on the 20Amp circuit, but not every time.
Seriously, there is no point that these circuits even get close to each other; they leave the panel and go in opposite directions to different floors -so it's not as if there could somehow be a crossed neutral or something.
My helper thinks that the screw gun motor is somehow creating a voltage drop in the panel and that this is tripping the 15A breaker. I definitely do not know how that would effect a AFCI, especially on a separate circuit, but that seems ridiculous to me. Unless maybe the power co is giving me a bad neutral and some of the voltage is going out the ground? But why would that effect the AFCI different circuit if it didn't already have a load on it?
I tried a different AFCI just in case the one I had was "sensitive". It still happened. I used a regular breaker and of course it doesn't trip.
I have heard (or read) that adjoining breakers can trip an AFCI, but I kinda thought that wasn't likely and that there must be something else wrong. Could this really be true?
Any insights?
Thanks in advance,
Greg
1 - 20 of 21 Posts
No; all these circuits were run on 12 or 14-2.
You're right that you can't share a neutral on a single pole AFCI circuit.
You can however if you get a 220 AFCI breaker (I have retro fitted a panel with these and they are about $110 each). The poor guy ran bedroom receptacles on 12/3 -you need to use 12/2/2 (to use single pole AFCI breakers) if you want to save time.
You're right that you can't share a neutral on a single pole AFCI circuit.
You can however if you get a 220 AFCI breaker (I have retro fitted a panel with these and they are about $110 each). The poor guy ran bedroom receptacles on 12/3 -you need to use 12/2/2 (to use single pole AFCI breakers) if you want to save time.
I've heard anecdotal reports of the heat AFCIs produce will create problems with the new '08 requirement that all 120v 15- and 20-a circuits be AFCI'd. Maybe an adjacent breaker is heating up the AFCI?
My only other suggestion is: Is it just the drywallers screwgun that is causing it to trip? If so, there's a problem with the screwgun.
My only other suggestion is: Is it just the drywallers screwgun that is causing it to trip? If so, there's a problem with the screwgun.
That would be also be my question. Is anything else causing it to trip?My only other suggestion is: Is it just the drywallers screwgun that is causing it to trip? If so, there's a problem with the screwgun.
Well, the light on the other circuit also caused it to trip.
Other than that I don't know; I didn't want to trouble shoot the AFCI circuit while the drywallers were working there making it trip by using a different circuit.
Remember: the screw gun is on a different circuit completely, so whether or not there is something wrong with it, what I really want to know is if there is some <bizarre> way that using the screw gun on a different 20Amp non-AFCI circuit could get a 15Amp AFCI circuit breaker to trip...
Tomorrow I will start under the assumption that there is a neutral to ground short on the AFCI circuit. Another thing that I remembered is that the romex wires all go through the same tomic connector; it wasn't packed or anything, but I always worry that the screw threads will score the romex.
The only explanation I can think of is that the screw on the tomic connector has scored both the 14/2 and the 12/2 and is creating a short across the 2 circuits.
I have also read about heat generation messing up AFCIs ...as I recall, someone posted on this message board that this will be a problem if the 2008 code actually kicks in and we have to start wiring houses with AFCI breakers on every circuit.
I doubt this is a heat issue; the panel cover is still off and there is no other construction going on right now...
Other than that I don't know; I didn't want to trouble shoot the AFCI circuit while the drywallers were working there making it trip by using a different circuit.
Remember: the screw gun is on a different circuit completely, so whether or not there is something wrong with it, what I really want to know is if there is some <bizarre> way that using the screw gun on a different 20Amp non-AFCI circuit could get a 15Amp AFCI circuit breaker to trip...
Tomorrow I will start under the assumption that there is a neutral to ground short on the AFCI circuit. Another thing that I remembered is that the romex wires all go through the same tomic connector; it wasn't packed or anything, but I always worry that the screw threads will score the romex.
The only explanation I can think of is that the screw on the tomic connector has scored both the 14/2 and the 12/2 and is creating a short across the 2 circuits.
I have also read about heat generation messing up AFCIs ...as I recall, someone posted on this message board that this will be a problem if the 2008 code actually kicks in and we have to start wiring houses with AFCI breakers on every circuit.
I doubt this is a heat issue; the panel cover is still off and there is no other construction going on right now...
My guess is that nether the screw gun or a heat build up it causing the said trip. Maybe the AFCI is doing exactly what it was built for, either detecting an arc or current in-balance between the two circuits. You may want to investigate your new work where the circuits come together for either possibility.
I had something like this. The wrong neutral was landed on the arch falt breaker. I looked at 3 times till and didn't see it. Then I completely dismanteled the circuit found nothing went back to the panel and finaly found that the guy that cut in the panel crossed the neutrals
Try another drill and see if it trips.My only other suggestion is: Is it just the drywallers screwgun that is causing it to trip? If so, there's a problem with the screwgun.
If this was the case it wouldn't matter if it was the drywaller's screw gun or not, the circuit would trip on ANY load..
The only explanation I can think of is that the screw on the tomic connector has scored both the 14/2 and the 12/2 and is creating a short across the 2 circuits.
If this was the case the AF breaker would never hold.The wrong neutral was landed on the arch falt breaker.
Somewhere along the line the circuits running together. I'd start from around a mid point in one of the circuits and just start pulling things apart. Sometimes you've gotta go through the whole dang thing until the problem is revealed.
Agreed.If this was the case it wouldn't matter if it was the drywaller's screw gun or not, the circuit would trip on ANY load.
Disagree. No load, this would hold, but ANY load would trip itIf this was the case the AF breaker would never hold.
Agreed. This is usually what ends up being done, If the problem isn't neutrals mixed up at the panel. (sigh....)Somewhere along the line the circuits running together. I'd start from around a mid point in one of the circuits and just start pulling things apart. Sometimes you've gotta go through the whole dang thing until the problem is revealed.
I thought of something new. Maybe you have a floating neutral. bond the neutral to the ground in that panel and see what happens. just use a piece of # 12. if that fixes it you need to remove it and bond it right at the main panel. Do any other exsisting circuits do it? try moving the breaker that trips or the 20 to the other phase. see what happens
So I took apart the tomic connector to see if the wires were cut by the screw threads and then I checked the neutral coming from the street. They both seemed to be OK. Which meant it was time to look in the mirror...
Ugh. Not one, but two problems:
My helper mixed two AFCI neutrals in the panel.
...and I had connected both circuits back together after I changed my mind about how I was going to split the circuits up -and never bothered to update the plans.
::embarrassed::
Here's the weird thing: both of those mistakes were on the 15Amp AFCI circuits; not the 20Amp circuit.
After I fixed the problems on the 15 A circuits, there was no problem with the 20 Amp circuit being used, so I don't get it.
Just to be safe, I did continuity tests on the 20 Amp circuit. No problems. So I put an AFCI on the 20Amp circuit to see if It would trip and potentially indicate bad insulation, but it didn't trip.
I really thought it was going to be the tomic connector or a bad neutral coming into the building. Naturally I'm disappointed that I made a stupid mistake (more forgiving toward my helper), but I'm really baffled by the AFCI breaker tripping when another circuit was used.
Ugh. Not one, but two problems:
My helper mixed two AFCI neutrals in the panel.
...and I had connected both circuits back together after I changed my mind about how I was going to split the circuits up -and never bothered to update the plans.
::embarrassed::
Here's the weird thing: both of those mistakes were on the 15Amp AFCI circuits; not the 20Amp circuit.
After I fixed the problems on the 15 A circuits, there was no problem with the 20 Amp circuit being used, so I don't get it.
Just to be safe, I did continuity tests on the 20 Amp circuit. No problems. So I put an AFCI on the 20Amp circuit to see if It would trip and potentially indicate bad insulation, but it didn't trip.
I really thought it was going to be the tomic connector or a bad neutral coming into the building. Naturally I'm disappointed that I made a stupid mistake (more forgiving toward my helper), but I'm really baffled by the AFCI breaker tripping when another circuit was used.
Glad you got it worked out. If there's one thing I've learned doing electrical troubleshooting is, every now and then you'll get something that you just can't explain. If it's all working let it be.
The odd thing about this is you still use tomic conn. They have been illegal for like 20 years. I want the credit here, I was the first one to say your neutrals where crossed
Wow, I never heard that. I've been using them for years, especially when fishing into an existing panel. What I like about using them in a new panel is that they are fast and they really keep all the wires bundled together in one place. That keeps the work really neat and clean. None of my inspectors has ever said anything about it -in fact, during the rough insp, I got complimented on how good the panel looked (my generally well-trained and hard working helper did it all).The odd thing about this is you still use tomic conn. They have been illegal for like 20 years.
You get credit on the board (I figured it out on Friday -but that's easy when you're right there).
Keep using them if your inspectors don't mind.
I've had inspectors give me grief for having more than one wire in a romex conn. I'm an M/C jockey mostly these days. I'm just finishing a Rite-Aid drug store. They spec. all pipe. You never see that any more. Everything was pipe in the walls and all. I was allowed to use M/C for lights only.
I've had inspectors give me grief for having more than one wire in a romex conn. I'm an M/C jockey mostly these days. I'm just finishing a Rite-Aid drug store. They spec. all pipe. You never see that any more. Everything was pipe in the walls and all. I was allowed to use M/C for lights only.
I am 64 years old, forgot too much. Help. I got customer wants 50ampere RV receptacle installed. RV is not on site. I assumed 2 hots, neutral and grounding. Four wire receptacle. His dealer tells me make sure 2 hots are same leg so no potential for 240 is present. So now dowe use 1 hot jumpered to other prong, and neutral and grounding. I don't know too much about RV stuff, inspector said he don't either. Please advise. Any info appreciated.
Start a new thread.
Your question is a good one, how ever you should start a new post with it so as not to confuse this one.
The codes for RV and parks have changed greatly, unless you have access to the new code book I would respectfully recomend some one else tackle this.:thumbsup:
I am 64 years old, forgot too much. Help. I got customer wants 50ampere RV receptacle installed. RV is not on site. I assumed 2 hots, neutral and grounding. Four wire receptacle. His dealer tells me make sure 2 hots are same leg so no potential for 240 is present. So now dowe use 1 hot jumpered to other prong, and neutral and grounding. I don't know too much about RV stuff, inspector said he don't either. Please advise. Any info appreciated.
Your question is a good one, how ever you should start a new post with it so as not to confuse this one.
The codes for RV and parks have changed greatly, unless you have access to the new code book I would respectfully recomend some one else tackle this.:thumbsup:
Your question is a good one, how ever you should start a new post with it so as not to confuse this one.
The codes for RV and parks have changed greatly, unless you have access to the new code book I would respectfully recomend some one else tackle this.:thumbsup:
thanks leland
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