Electrical Help Please!

[index]

I like to think I am above average in the DIY electrical work. I worked on a crew for a summer in college and have rewired two of my own houses now getting all the proper permits and inspections of course.

About two months ago I was outside on a ladder painting and heard very loud popping. It sounded kind of like a pneumatic roofing nailer in rapid succession and it seemed to be coming from the back of the house outside. My wife came out and said the lights went on and off for several seconds and there was loud popping in the basement.

I went to the panel and it smelled as if something had burnt and two circuit breakers had faulted; the breakers were lighting and bedroom circuits with almost 0 load. Our panel uses only AFCI or AFCI/GFCI combination breakers. One of the breakers would not hold a load and immediately tripped as soon as it is turned on. I removed the first connection in the line and confirmed the AFCI breaker was toast.

My thoughts were there was a power surge or we overloaded the panel. We were running the dryer 25A, oven 25A, and the A/C (30A) at the time. I checked our smart meter and it read a max draw of 82 amps. We have a 100A service, but I wouldn't say this was the first time all those devices were used together. Also, the main 100A breaker did not trip. Could it have been a power surge? We have a whole house surge protector (Siemens breaker type).     

All has been fine the last two months and we have continued to use the high draw appliances like normal.

Yesterday, I was working in the garage and noticed the led lights were flickering; I turned the lights off. I went on to use a miter saw and it seemed to only be spinning at half speed and bogged down when cutting a 2x4. My wife came out and said the living room breaker tripped (separate from the garage breaker where I was using the miter saw), there was no loud sound this time. At the time we were running the dryer but no other high draw appliances. The smart meter said we were pulling 24 amps. The living room breaker that tripped had an led tv playing music on and a couple of led lights on it. I reset the breaker and continued working outside. The saw seemed to have returned to normal and the lights in the garage stopped flickering.

What could be going on? The only thing consistent between the two events were both happened on a Sunday afternoon and the dryer was running at the time.

[Jon Bon]

Well this is all second hand from what I have heard.

Basically AFCI breakers are more trouble then they are worth. They are a result of electrical equipment manufactures lobbying those folks that write the code. So now it is code that houses have them.

The issue is they are too damn sensitive, they trip all the time when they should not be. So lots of guys (I have heard) swap them out for GFCI only or even  standard breakers.

Again this is all second hand but it sure sounds like what might be happening to you. Do some googling on AFCI breakers.

[index]

Well this is all second hand from what I have heard.

Basically AFCI breakers are more trouble then they are worth. They are a result of electrical equipment manufactures lobbying those folks that write the code. So now it is code that houses have them.

The issue is they are too damn sensitive, they trip all the time when they should not be. So lots of guys (I have heard) swap them out for GFCI only or even  standard breakers.

Again this is all second hand but it sure sounds like what might be happening to you. Do some googling on AFCI breakers.

Yeah I know a lot of electricians have opinions about AFCI's. In my experience nuisance tripping isn't too bad. It is mostly the result of cheap or old electric motors like and old vacuum or power tools from Harbor Freight. I can see electricians disliking callbacks when a HO goes to use a circular saw and repeatedly trips the breaker. I take that to mean I should replace the circular saw with something with a more efficient motor and not have the problem anymore.

I looked into it quite a bit. At the time I had some old cloth wiring and knob and tube in the house that I had a smoldering fire occur in a wall that didn't result in any damage but was alarming. I installed the AFCIs more to protect from another fire due to my old wiring until I could get to it.

Here are the average numbers, you can ball park them to decide if you are more or less likely to have a problem:

FEMA has a lot of literature about house fires. Their literature shows 10% of house fires are attributed to electrical problems:



 Of these: cooking, arson, and smoking materials can be prevented by being responsible which leaves heating (15%) and electrical (10%) as potential fires sources hard to prevent. This study (https://www.usfa.fema.gov/downloads/pdf/statistics/v19i8.pdf) indicates about 44% of electrical house fires could be prevented by AFCI breakers.

Installing AFCI breakers is going to run $400 to $800, and you will need to deal with the nuisance trips until you replace your offending devices (if you have any). It lowers your total chance of a house fire by 4.4% or the chance a responsible person that watches the stove, doesn't smoke in the house, and doesn't intentionally burn their house down by about 18%.

Your chance of having a house fire due to heating and electrical in any given year is 1/1400 which is a 1/50 chance over 30 years. Installing AFCIs reduces this to 1/60 chance.

[Papa bear]

A lot of old knob and tube had a shared neutral.  Afci and gfci breakers do NOT like shared neutrals. 

I’m posting more to follow, I want to see the resolution on this.  I have similar electrical experience to you, and I’m stumped.

Do you know if your service is truly at 100amps? Maybe it was 60 but somewhere down the road, the panel got replaced with 100amp breaker and wiring never was upgraded.


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[index]

A lot of old knob and tube had a shared neutral.  Afci and gfci breakers do NOT like shared neutrals. 

I’m posting more to follow, I want to see the resolution on this.  I have similar electrical experience to you, and I’m stumped.

Do you know if your service is truly at 100amps? Maybe it was 60 but somewhere down the road, the panel got replaced with 100amp breaker and wiring never was upgraded.


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Yeah to use an AFCI or GFCI breaker on a shared neutral you have to use a MWBC breaker at $80 a pop.

The service is 100A. I ran new wires and upgraded from 60A 5 years ago.  I'm kicking myself now for not going 200A, before electric vehicles started to take off...

100A service, Siemens pannel with all afci, afci/gfci, and a whole house surge protector. I finished upgrading the wiring two years ago to all 12ga with 20A breakers nm or conduit in the attic where critters could get to it.

[zolotiyeruki]

I'd like to chime in, and add my voice to those who dislike AFCI breakers. They literally cost ten times as much as a traditional breaker, and are super duper sensitive.  I'm in the process of finishing our basement, and this stupid things mean I have to run an extension cord from an existing outlet in order to run my miter saw or even a vacuum.

I don't think they will last long after the inspector leaves.

[BDWW]

Not to derail the afci hate train, but from that initial description, I'd be more concerned that it actually did it's job.  That pneumatic sound it you describe sounds like moisture arcing to me.

I'd be concerned there's a bare/melted wire somewhere that's arcing to moist wood or something similar.

[Wrenchturner]

Not to derail the afci hate train, but from that initial description, I'd be more concerned that it actually did it's job.  That pneumatic sound it you describe sounds like moisture arcing to me.

I'd be concerned there's a bare/melted wire somewhere that's arcing to moist wood or something similar.

Agreed, probably other issues here, from a cursory read you're describing voltage drops among other things, GFCIs don't cause voltage drops or intermittent/flickering power in my experience.  They either stay closed or open very quickly.

[index]

Not to derail the afci hate train, but from that initial description, I'd be more concerned that it actually did it's job.  That pneumatic sound it you describe sounds like moisture arcing to me.

I'd be concerned there's a bare/melted wire somewhere that's arcing to moist wood or something similar.

Agreed, probably other issues here, from a cursory read you're describing voltage drops among other things, GFCIs don't cause voltage drops or intermittent/flickering power in my experience.  They either stay closed or open very quickly.

Thinking on this, it could a problem with the service drop to the house. If the live and neutral wires came close enough to to cause arcing between the two it would explain the pneumatic snapping noise. I thought it was coming from outside the house, my wife said she heard it from the panel. She was in the basement, but i suppose the panel could be making a racket if it was shorting outside...

Also, I cannot trace the lines from each transformer perfectly, but it appears there are 16 or more houses fed by 3 transformers. Maybe the load with everyone home sunday afternoon was enough to cause a small voltage drop last weekend? I don't know why it would trip an AFCI in the house though; or why after resetting it, everything worked normally and continues to work normally.

The only high draw appliance running was a cloths dryer that Sunday, maybe the dryer is malfunctioning? It seems strange it would cause a whole house voltage drop though and trip a unrelated circuit. The dryer is on a 4 wire 220, but the white wire is tucked away as the plug is only a three prong plug. I will investigate tonight, maybe there is arcing to the neutral or ground... 

The whole house voltage drop is what has me confused. The circuit that tripped was a 120V branch protected by and afci. If there was any arcing between hot neutral or ground, it would immediately trip and shouldn't allow "leakage" that could cause a 5 min or so voltage drop.

[Papa bear]

You seem big on electrical safety, having all the afci breakers.  Why not switch your plug out on the dryer and the receptacle to one that handles the ground? Seems like low hanging fruit. 

I don’t imagine it had anything to do with this, but in the off chance it’s arcing in the current receptacle, would be worth the hour of work.


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[zolotiyeruki]

You seem big on electrical safety, having all the afci breakers.  Why not switch your plug out on the dryer and the receptacle to one that handles the ground? Seems like low hanging fruit. 

I don’t imagine it had anything to do with this, but in the off chance it’s arcing in the current receptacle, would be worth the hour of work.

AFCI breakers are now required by the US National Electric Code on all new work.

[Papa bear]

You seem big on electrical safety, having all the afci breakers.  Why not switch your plug out on the dryer and the receptacle to one that handles the ground? Seems like low hanging fruit. 

I don’t imagine it had anything to do with this, but in the off chance it’s arcing in the current receptacle, would be worth the hour of work.

AFCI breakers are now required by the US National Electric Code on all new work.

I realize that. His house is not new work. Also, not all jurisdictions follow current NEC. And not all inspectors follow the rules if they do follow current NEC.

Doesn’t change the fact that OP is up on safety and his current receptacle and plug aren’t to current standards.  Is it a problem? 99.99% of the time no.  But it’s an easy, cheap, and quick fix.  Figured it was worth a shot here as they mentioned it as a potential problem point.


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[Wrenchturner]

Okay I read this through.  I don't have much to offer.  Breakers that cycle fast or get burned or smell like burning suggests a different issue than the breaker.  Not a typical failure mode unless something else is wrong. Also strange that the breakers that got roasted were not in use (or low load on them).

This part seems weird:
"The dryer is on a 4 wire 220, but the white wire is tucked away as the plug is only a three prong plug."

I don't do any 220v work but it sounds like this might be the culprit.  Maybe there's backfeeding on the ground circuit from the inrush on the dryer? 

[index]

Okay I read this through.  I don't have much to offer.  Breakers that cycle fast or get burned or smell like burning suggests a different issue than the breaker.  Not a typical failure mode unless something else is wrong. Also strange that the breakers that got roasted were not in use (or low load on them).

This part seems weird:
"The dryer is on a 4 wire 220, but the white wire is tucked away as the plug is only a three prong plug."

I don't do any 220v work but it sounds like this might be the culprit.  Maybe there's backfeeding on the ground circuit from the inrush on the dryer?

We ran a load of laundry last night/this morning. The dryer was running, everything was fine. I opened the door to throw something else in and hit the start button again and the living room circuit (afci) tripped. I could not get the dryer to run and the living room circuit to hold at the same time. When I had the dryer off, the 30A dryer circuit and 20A afci living room circuit held, but I was getting the voltage drop symptoms I talked about earlier (motor in two fans slowed down, lights dimmed/flickered).
When I turned off the living room breaker, the voltage drop went away.

I inspected the dryer wiring at the plug and found the ground tucked in the back of the box (4th unused wire for my 3-wire plug) may have been able to contact one of the screws on the back of the 220V outlet, there were no burn marks. I coiled it and pushed it to the back of the box and am sure it cannot touch anything now. I turned on both the 30A dryer and 20A living room breaker and both held. Started the dryer, no problems. The voltage drop symptoms disappeared.   

Now this has been an intermittent problem. I have only noticed it twice (living room breaker tripped both times) though we have had voltage drop symptoms before, I just thought it was on the power company side. I don't know that the ground was contacting a live screw in the plug and it could have just been a coincidence everything started working again.

So I think it could be one of 3 things:

1. Backfeeding over the ground at the dryer plug. Which doesn't make sense why it would only happen when the dryer is on. Wouldn't the backfeeding be happening all the time.

2. The 20A afci could have a problem where it is shunting power from the hot directly to the neutral bar causing the voltage drop. These are pretty sensitive though and it being intermittent and somehow related to the dryer seems strange.

3. The dryer motor is going out and pulling too many amps on one side of the breaker. I don't think there is a capacitor on this model but I am just relating it to how an AC can dim the lights when the run capacitor starts going out and the motor draws too much current. The (Model: LE4440xWW0) dryer is probably 25 years old. I checked for parts and the Drive Motor is $125.

Do the symptoms sound like backfeeding at the dryer plug? Why would turning off the 20A breaker stop the issue?

If it happens again, next step is to replace the living room breaker, then the drive motor or dryer...

[Wrenchturner]

Unused wires in junction boxes should be capped with a marrette and taped to fasten, consult your electrical code.

I recommend calling an electrician.

At some point I'll try to read through your post and see if I can help further.

[Wrenchturner]

Okay, I read this through.  I think the biggest suspect is your three prong dryer.  Not too sure about the backfeeding but sometimes that will occur when power is cut to a motor(switched off) and the motor continues to turn, pushing amps back into the source.  I've seen this with DC low voltage motors but I don't know about a dryer.  There's probably a lot of noise making its way into your ground circuit from the brushed motor as well.

The voltage drop is pretty concerning because that usually suggests heavy amp draw.  Could be a second issue.  Perhaps you can identify which leg is going where--presumably the dryer is using both legs from the panel and maybe you can trace the issue to the leg that is also powering the living room.

Really what you want is for the dryer to start using a neutral imo.  Your dryer predates panel GFCIs.

You could try swapping the living room breaker to test that issue also.

[index]

Interesting development:

I was using a shop vac this weekend and the breaker tripped. It is an afci breaker and it is not uncommon for the motor in the shop vac to trip the afci. I went down to the box and one leg of the whole house surge protector was also tripped. I tried to reset the whole house surge and it immediately tripped and I could smell burning.



The burnt out surge protector leg was the same leg as the dryer motor, basement lighting circuit (dimming), basement duct fan (where you could hear the voltage drop). And the opposite leg of the furnace, microwave, and bedroom fan we run often which has never indicated a voltage drop.

I swapped the surge protector double breaker for two 20A normal breakers and everything worked as it should.

I am beginning to think the initial event may have been a power surge that damaged one leg of the surge protector. Whenever an older motor would start the malfunctioning surge protector would shunt power from hot to neutral causing a voltage drop on one leg. The surge protector malfunctioning would explain why it is so intermittent and why the problem has been slowly getting worse but seemed to be initiated by the event where we heard the pneumatic sounding popping coming from (maybe the panel, maybe the outdoors). Any time we have a voltage drop, it seems to be initiated by the dryer which is a large electric motor.

What do you think? Could a broken surge protector be grabbing and shunting the surge from the dryer but not "letting go" and continue to shunt power below its initial clamp causing the voltage drop. This model does have a low initial clamp of 240V compared to most whole house spd's.     

[fixie]

Not to derail the afci hate train, but from that initial description, I'd be more concerned that it actually did it's job.  That pneumatic sound it you describe sounds like moisture arcing to me.

I'd be concerned there's a bare/melted wire somewhere that's arcing to moist wood or something similar.

Agreed, probably other issues here, from a cursory read you're describing voltage drops among other things, GFCIs don't cause voltage drops or intermittent/flickering power in my experience.  They either stay closed or open very quickly.

That's exactly what I thought when reading about the disturbing popping sound with no resolution.  The cells in wood could have been cavitating from the heat of an electrical short...
Not to scare you or anything....
-fixie

[index]

Not to derail the afci hate train, but from that initial description, I'd be more concerned that it actually did it's job.  That pneumatic sound it you describe sounds like moisture arcing to me.

I'd be concerned there's a bare/melted wire somewhere that's arcing to moist wood or something similar.

Agreed, probably other issues here, from a cursory read you're describing voltage drops among other things, GFCIs don't cause voltage drops or intermittent/flickering power in my experience.  They either stay closed or open very quickly.

That's exactly what I thought when reading about the disturbing popping sound with no resolution.  The cells in wood could have been cavitating from the heat of an electrical short...
Not to scare you or anything....
-fixie

I'm not sure you could get moisture arcing that went on for 10 seconds or so and AFCI and not have it trip. Also, there was a circuit that was fried in the box. This was on the same leg as the half of the surge protector that failed last weekend. My thought is the pneumatic sound could have been arcing between one leg and the neutral at the service entrance due to a power surge. My wife probably heard several breakers trip in the box along with the sound I heard outside the house.

I replaced the surge protector 3 days ago and my problems seem to have vanished. I am starting to think it was a faulty surge protector shunting power to neutral across the damaged leg. I will report back if the problems come back; it has been a biweekly problem lately while the dryer is running. I've been doing extra loads of laundry this week to test!

[Ripple4]

Might be worth the time to check that you have a correct neutral connection. do this by measuring for "120v" between each pole of a 240v breaker and the neutral inside the load center panel. if the neutral is floating it could be a 200v/40v split instead of 120/120 depending on which 120v loads are running. 240v appliances will work fine with a badly floating neutral because pole to pole voltage is controlled by the utility. the 120v stability is a function of how good the wire and earth connections are between the center tap of the transformer out on the pole and your load center.

[index]

Update - this is resolved!

The power had been working fine for three weeks, then Sunday, the voltage drop returned. This time it did not improve. I called the utility power outage line and explained what was going on. They sent a lineman who checked their side of the service - transformer to electric meter. The test showed a 65 volt drop. They got up on the pole and found the neutral had almost completely melted and welded itself to one of the incoming hots. Half an hour or so later, the issue was resolved.

Lessons learned - make sure your main panel is grounded well and call the utility when there is a power issue you cannot get to the bottom of.

[zolotiyeruki]

Update - this is resolved!

The power had been working fine for three weeks, then Sunday, the voltage drop returned. This time it did not improve. I called the utility power outage line and explained what was going on. They sent a lineman who checked their side of the service - transformer to electric meter. The test showed a 65 volt drop. They got up on the pole and found the neutral had almost completely melted and welded itself to one of the incoming hots. Half an hour or so later, the issue was resolved.

Lessons learned - make sure your main panel is grounded well and call the utility when there is a power issue you cannot get to the bottom of.

Oof, that's a nasty fault waiting to happen.  Glad you got it fixed!