AFCI Trips Randomly

[bad_idea]

The AFCI breaker feeding my daughter's room trips randomly. Used to be once every couple months, recently has escalated to once or twice a week. House was built in 2005, and has a Square D Homeline panel. I replaced the AFCI breaker, hoping that would solve the issue. It did not. The circuit has the following items on it: ceiling fan/light with dual switch to control each function (14/3 between switch and fixture), closet light with switch, smoke detector (replaced a few months ago because one failed), and six receptacles.

The following items are plugged into the outlets: night light, alarm clock, and desk lamp. These items stay plugged in, breaker does not trip when any one item is flipped on/off.

I used a thermal camera to look for hot spots - everything looks good there.

I plan to pull open the receptacles, switches, and fixtures to look for loose connections tomorrow. Anything else I should look for while I'm in there? Other causes I should look into?

 

[larry4406]

Motor brushes on ceiling fan if that type?

Vacuum cleaners were the culprit for me.

 

[sparky 1971]

Try putting one of these in and I bet your problems go away.

Square D™ Homeline™ 15-Amp 1-Pole Standard Circuit Breaker

Square D Homeline 15-Amp One-Pole Circuit Breaker is used for overload and short-circuit protection of your electrical system. This breaker is compatible with Homeline load centers and CSED devices. The ANSI-certified and UL-listed unit is rated for 120/240 VAC and 10,000 AIR. Homeline circuit...

www.menards.com

I'm not going to waste any time reading this, but nuisance tripping is the topic, I only know of one way to eliminate it.

Understanding AFCI (Arc-Fault Circuit Interrupter) Challenges and Addressing Nuisance Tripping > What's New > Leviton Blog

Welcome to the Leviton Blog > What's New > Understanding AFCI (Arc-Fault Circuit Interrupter) Challenges and Addressing Nuisance Tripping section of the Leviton Blogsite. This section has the following description: The National Electrical Code® (NEC®) has required Arc-Fault Circuit Interrupters...

blog.leviton.com

 

[wyliesdiesels]

snake oil got ya. replace as suggested above by sparky1971

 

[bad_idea]

I've read up on AFCIs, I know they are a nightmare. My concern is this is the only circuit that has had nuisance trips, the other four AFCIs in the house have not tripped once in the six years we have owned the house.

The ceiling fan is the exact same unit in the other bedrooms (each on AFCI breakers). My wife insisted we replace every ceiling fan in the house to match a few years ago.

I'll do an 'open and inspect' on all of the boxes today. If I don't find anything, I'll look at swapping in a standard breaker.

 

[PCustoms]

Well this one almost sounds like it's properly working.

Haven't smoked detectors required a dedicated circuit for a while? The combo of items on one breaker makes me think and old circuit/one that has been added to.

I'd do a little more investigation before writing off to afci as snake oil.

Note: I'm not a fan of them either

 

[PCustoms]

@bad_idea can you provide a little detail on how you used the thermal camera? I'm assuming you didn't just stand in the doorway and point it at each device...

 

[SlappyWhite]

When opening the outlets check to see if they are backstabbed, if they are move the wires to the screws. This is a common source of trips. Also make sure any pigtails/connections are tight. Like others noted, check anything with a motor that uses brushes, another possible cause.

They can also trip if current is bleeding to ground, not a full GFCI level protection but circuit will trip it just at a higher current (I think >50ma or so). I have had a damaged wire cause tripping, a neutral to ground "leak".

 

[sparky 1971]

Well this one almost sounds like it's properly working.

Tripping doesn't mean anything. I've been there and done that. Tried swapping AFCI breakers around d to verify and the same breaker was tripping no matter the circuit.

Haven't smoked detectors required a dedicated circuit for a while?

Never unless it's a local ammendment.

The combo of items on one breaker makes me think and old circuit/one that has been added to.

Sounds like a typical bedroom circuit to me. I wouldn't be surprised if the smoke detector isn't on the same circuit but it could be. If it is on the bedroom circuit, all of the detectors in the house should be as well.

I'd do a little more investigation before writing off to afci as snake oil.

Note: I'm not a fan of them either

They are snake oil whether they work properly or not.

 

[rooster59]

Backstabbed cheap outlets are the devil. Those and Marie Kondo.

 

[bad_idea]

@bad_idea can you provide a little detail on how you used the thermal camera? I'm assuming you didn't just stand in the doorway and point it at each device...

I pointed the thermal camera at each device ~2-3' away. The heat of each device was within a few degrees of the adjacent sheet rock.

 

[bad_idea]

Well this one almost sounds like it's properly working.

Haven't smoked detectors required a dedicated circuit for a while? The combo of items on one breaker makes me think and old circuit/one that has been added to.

I'd do a little more investigation before writing off to afci as snake oil.

Note: I'm not a fan of them either

The smoke detectors were all wired into the same circuit, the circuit for my daughter's room. The wiring is all original, no signs of additions.

 

[bad_idea]

So... I found the issue. Long story short, the smoke detector in the master bedroom had the neutral for the detector wired to ground. Plain as day, white wire and ground wire under the same wire nut.

Long story long - some times I fear I am a dumb ***. I went to the breaker to secure power to the circuit and realized I replaced the wrong breaker. I swapped the two breakers and now the new breaker on the trouble circuit was tripping immediately, every time.

I opened all of the receptacles up to find they were back stabbed. I removed all of the receptacles, identified the receptacle box the power cable from the breaker was coming from (turned breaker on and probed wires until I found 120v. The first box from the breaker had three cables in it - one from the breaker, second to the next outlet, and the third went to the smoke detectors. I installed the receptacle, turned the breaker on, it tripped. I removed the smoke detector wire from the junction, turned the breaker on and it stayed on.

I then went around the room installing receptacles and turning the breaker on between each one, breaker did not trip again. Once I had the entire circuit hooked up (with new receptacles with the wires under the side screws, not back stabbed), I then opened up the smoke detector boxes. I found the neutral from the pigtail wired to the ground in the box for the detector in the master bedroom. Swapped the neutral to the neutral and now the entire circuit functions correctly.

 

[SlappyWhite]

As the fault is staying with the circuit and not the breaker (breaker was swapped and the new one keeps tripping). This means to me that something is wrong in the circuit or with something plugged into it.

Also to add to my previous post in this tread. A device that is producing a large amount of EMI can also cause the trip. Look for cheap dollarstore phone chargers etc.

Edit, you found the problem!

 

[sparky 1971]

I'm confused. It was tripping randomly in post #1, then switching the breakers caused it to trip immediately in #13. If the smoke was wrong from the beginning the AFCI should have immediately tripped on day one. If what I am thinking is true, the original breaker was junk out of the box.

 

[Sumboodie]

Well this one almost sounds like it's properly working.

Haven't smoked detectors required a dedicated circuit for a while? The combo of items on one breaker makes me think and old circuit/one that has been added to.

I'd do a little more investigation before writing off to afci as snake oil.

Note: I'm not a fan of them either

That seems like a horrible idea. If on a lighting circuit it'd be noticed fairly quickly. On it's own, maybe never.

 

[bad_idea]

I'm confused. It was tripping randomly in post #1, then switching the breakers caused it to trip immediately in #13. If the smoke was wrong from the beginning the AFCI should have immediately tripped on day one. If what I am thinking is true, the original breaker was junk out of the box.

My thoughts exactly - the original was junk from day one.

 

[wyliesdiesels]

I'm confused. It was tripping randomly in post #1, then switching the breakers caused it to trip immediately in #13. If the smoke was wrong from the beginning the AFCI should have immediately tripped on day one. If what I am thinking is true, the original breaker was junk out of the box.

bingo. you beat me to it

 

[wyliesdiesels]

Well this one almost sounds like it's properly working.

Haven't smoked detectors required a dedicated circuit for a while? The combo of items on one breaker makes me think and old circuit/one that has been added to.

I'd do a little more investigation before writing off to afci as snake oil.

Note: I'm not a fan of them either

as said above you definitely dont want them on a dedicated circuit because if it trips or stops working, you may never know. and then your smokes stop working. cant always rely on battery backup either.

 

[SlappyWhite]

as said above you definitely dont want them on a dedicated circuit because if it trips or stops working, you may never know. and then your smokes stop working. cant always rely on battery backup either.

Code here requires smoke detectors to have a regularly used light on the same circuit. When the light stops working you know the breaker is tripped (or the bulb is out...).

My boiler, fridge and smoke detectors are the only three 120v circuits without CAFI (AFCI) in my house. Smoke detectors are also prohibited to be on arc fault here by code.

 

[PCustoms]

I'll have to look later and see how I wired my smokes pretty sure I looked up what the code was followed that to the t. For some reason was thinking they were dedicated...

 

[sparky 1971]

I'll have to look later and see how I wired my smokes pretty sure I looked up what the code was followed that to the t. For some reason was thinking they were dedicated...

They can be but nothing says they have to be as far as the NEC goes. I put them on a dedicated circuit but that's only because that's the way I was taught way back when...

 

[larry4406]

The sparkles at the day job put the smokes on a dedicated circuit.

They do include the attic radon pump prewire on that circuit for convenience as the smokes are a small load.

 

[bad_idea]

as said above you definitely dont want them on a dedicated circuit because if it trips or stops working, you may never know. and then your smokes stop working. cant always rely on battery backup either.

Ohh, but you can rely on the battery backup. When one of the batteries run low, they all start going off. At 3 am. That was what finally spurred me to fix the issue. The fire alarm went off at 3 am the other day. My daughter is 5 years old and seldom turns on her light. Her light was out long enough to run the batteries down on one of the detectors.

 

[Dagny]

Wow need a job?

 

[wyliesdiesels]

Ohh, but you can rely on the battery backup. When one of the batteries run low, they all start going off. At 3 am. That was what finally spurred me to fix the issue. The fire alarm went off at 3 am the other day. My daughter is 5 years old and seldom turns on her light. Her light was out long enough to run the batteries down on one of the detectors.

You are the exception to the rule. You know how many people let those batteries die after hearing it beep for days on end?

 

[Meursault74]

You are the exception to the rule. You know how many people let those batteries die after hearing it beep for days on end?

Nah, they just pull out the battery to stop the beeping. If they can stand the beeping for days, they have some fortitude. If mine starts to beep, I'll pull the battery quickly. If I don't have another 9v battery for it, I'll get another battery ASAP.

 

[bad_idea]

These do not do the chirping ****. They sound the fire alarm at 150db. At 3AM. We have been in the house for 6 years. The fire alarm has gone off 5 times now for various dumb problems. Each time has been between 2-3AM. NEVER during the middle of the day.

 

[sparky 1971]

I've found that the damned things use the batteries to chirp when the power is out and they use 120 volt to chirp when the batteries are dead. Which reminds me, I need to put the new SD up in my living room, I'm almost so used to seeing the wires hanging down that I don't notice it anymore.

 

[wyliesdiesels]

hmm weird. ive seen several interconnected smokes that are hardwired with battery backup and they do indeed do the low battery chirp

 

[larry4406]

I’ve found on smokes when they chirp you need to disconnect from house power, yank battery, then push test to bleed off capacitors.

Then new battery and reconnect.

 

[mike93lx]

I've found that the damned things use the batteries to chirp when the power is out and they use 120 volt to chirp when the batteries are dead. Which reminds me, I need to put the new SD up in my living room, I'm almost so used to seeing the wires hanging down that I don't notice it anymore.

Tomorrow's a better day for that

 

[sparky 1971]

Tomorrow's a better day for that

I've been saying that for about three years now. I have one for the second time. The first one I bought sat on the kitchen table long enough that Mrs. Sparky put it in a drawer where it was almost forgotten about. Then I had to trim out a room addition and realized I had forgotten about a smoke detector. I needed three but had only purchased one on the way home the day before. I about tore the house apart until I found that smoke. That gave me a reset on the clock and I picked up another about a month ago. I have no idea where it's at though...

 

[mike93lx]

I've been saying that for about three years now. I have one for the second time. The first one I bought sat on the kitchen table long enough that Mrs. Sparky put it in a drawer where it was almost forgotten about. Then I had to trim out a room addition and realized I had forgotten about a smoke detector. I needed three but had only purchased one on the way home the day before. I about tore the house apart until I found that smoke. That gave me a reset on the clock and I picked up another about a month ago. I have no idea where it's at though...

Tomorrow... The day that never comes

 

[bad_idea]

Wow need a job?

No thanks.

While I enjoyed the troubleshooting process, I could do without it on a daily basis. Besides, I would never make any money with the amount of time it took me to figure out.

 

[PCustoms]

Any chance you have a pic of the old breaker?

Still trying to figure out how a neutral/ground bond at the smoke would trip an AFCI...

 

[walta]

hmm weird. ive seen several interconnected smokes that are hardwired with battery backup and they do indeed do the low battery chirp

If by beep you mean all 18 interconnected Kidde alarms screaming at full volume while you squint staring at the tiny LED in a feeble attempt to figure out if one is winking a different pattern, then you and I have different pain thresholds.

The only thing I know for sure is blowing out the alarms and replacing the batteries ever 12 months has keep the silent.

Walta

 

[justsam]

If by beep you mean all 18 interconnected Kidde alarms screaming at full volume while you squint staring at the tiny LED in a feeble attempt to figure out if one is winking a different pattern, then you and I have different pain thresholds.

The only thing I know for sure is blowing out the alarms and replacing the batteries ever 12 months has keep the silent.

Walta

Nest Protect - Each unit will verbally announce trouble and location of troubled unit. Alerts such as loss of power, low battery, carbon monoxide, fire, etc. Also will alert and show on app. Each unit also has a sounder if all else fails. The sounder is tested each month via a built in microphone, and will give a brief unique tone sequence.

 

[bad_idea]

AFCI Troubleshooting Bulletin

I do not have a picture of the old breaker available, but I found the above document for the AFCI I had installed. I found it cruising the net looking for troubleshooting information. On sheet 7 it describes a 'inadvertent neutral to ground fault'.

 

[Jim greengo]

Any shared neutrals with other circuits?