Arc Fault Nusiance Trips


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Old 04-03-21, 11:31 AM
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Arc Fault Nusiance Trips

I have an accessory dwelling unit on its own sub panel (new construction) where I am getting occasional arc fault trips on the 2 kitchen counter circuits and a dedicated circuit for the fridge. There is no apparent pattern except that they only occur when the range is turned on. Very strange.

Anyone have ideas on what could be happening here?
 
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Old 04-03-21, 03:49 PM
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How old are the breakers? First generations of AFCI breakers did have some issues with nuisance tripping.
 
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Old 04-03-21, 04:24 PM
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Breakers are 3 years old. The fridge breaker trips randomly only when the range is on. The 2 Kitchen counter circuits trip randomly when a hot pot or microwave is running and the range is on. I replaced the range breaker since it was a cheap breaker but hesitate to replace the 3 arc faults without a bit more trouble shooting. I have checked all connections and there are no shared neutrals. The fridge circuit is dedicated. The 2 counter top circuits each have a gfi receptacle between the breaker and downstream receptacles.
 
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Old 04-03-21, 04:55 PM
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How old are the breakers? First generations of AFCI breakers did have some issues with nuisance tripping
my $0.02 is find a normal breaker for the circuit amperage and panel type but that is not code these days.

Also what is an "Accessory Dwelling unit" is that a Mother in law or sublet type thing? or a she or he shed? Never heard of accessory dwelling unit before.
 
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Old 04-03-21, 05:11 PM
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What kind of range? Inductive? Gas? And, what company made the AFCI’s?
 
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Old 04-03-21, 06:54 PM
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Accessory Dwelling unit (ADU) a mother in law apartment without the gender. It is what they are called in the land use code.
The range is generic electric (should have mentioned that) nothing fancy. The AFCI's are Siemens. I know there was a recall on some of their AFCI's but mine were bought 3 years ago so should not have the same problem as the recalled ones.
 
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Old 04-03-21, 10:12 PM
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Accessory Dwelling unit (ADU) a mother in law apartment without the gender. It is what they are called in the land use code.
The range is generic electric (should have mentioned that) nothing fancy. The AFCI's are Siemens. I know there was a recall on some of their AFCI's but mine were bought 3 years ago so should not have the same problem as the recalled ones.
Ah so a mother or father in law but the generic term got it thank you

So the range is just electric elements with no clock timer or any other "fluff" as the elements are just 240V resistance loads no neutral needed wired just between L1 & L2

The only thing I can think of is the range receptacle or cord on the range (4-wire cord but the ground & neutral jumper was left attached) is wired wrong does it trip as soon as the range is turned on or does it take time to trip?
Maybe a panel neutral ground is wired wrong as a sub panel they should be separate and have 4 wires between the 2 panels (hot hot neutral ground)
 
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Old 04-04-21, 10:31 AM
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Sub-panel is wired correctly. I pulled out the range and checked that the ground/neutral jumper was removed. it was. I moved the fridge breaker away from the range breaker thinking there might be some electrical interference affecting the fridge arc fault breaker (grasping at straws here}. Unless someone has any suggestions I am going to leave it as is and give the tenant a form to log future trips. If the trips continue I will just have to bite the bullet and buy new arc fault breakers.
 
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Old 04-04-21, 08:31 PM
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When you reset a Siemens breaker it should show LED if arc or ground fault that may help. Siemens document https://www.downloads.siemens.com/do...id1=BTLV_40705

Wondering if the range turning on is causing a significant voltage drop that the breakers don't like. Should measure.
 
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Old 04-04-21, 08:47 PM
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Breakers are showing the arc fault LED when tripped. I think all of the trips occur when the range is on and another appliance (fridge or counter top appliances). They seem to occur after the juice is flowing rather than just when it turns on. It is also very random, occurring only about once a week.

the electric range is the smallest one you can buy. It is on a 40 amp breaker and shouldn't draw much but I will check it once I find my muiltimeter.
 
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Old 04-05-21, 01:53 AM
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Seems odd that three AFCI breakers are failing together at the same time especially since they are only 3 years old. Be sure if you do buy three new ones and you find it does not solve the problem that you are able to return the 3 news ones you bought.

I would think the issue is being created by something else other than failing AFCI breakers.
 
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Old 04-05-21, 03:52 PM
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I think it must be something else as well.
 
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Old 04-06-21, 02:27 AM
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DavidJ whatever you do do it quickly. Since this is new construction and you find the AFCI breakers are not at fault the electrician must find the problems/causes. This should not be happening. The AFCI breakers if not faulty are doing their job of protecting you and your property from arc faults which may result in fire. Not trying to scare you. Since this is new wiring etc either there is an issue with one of the appliance on those circuits (which seems strange that 3 circuits would have 3 different things on them to cause an arc trip) or there is an issue overall - either way it must be solved. If the electrician does not do this that wired the place then in the future it will cost you a lot of money to deal with then instead of now.

The one thing you can do if you feel comfortable working in the panel is instead of buying 3 new AFCI breakers swap them for other AFCI breakers you may have in the panel now and see if the same issue remains. If it does then there is a problem with the circuit.

Actually though my feeling would be that since this is new construction and new wiring materials etc that the first thing that should be done is to contact the contractor to have the electrician come over and deal with it as soon as possible. I would think it is the contractor's and electrician's responsibility to be sure your electrical system is safe. I would not even touch anything and just get the electrician there.
 
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Old 04-10-21, 09:13 AM
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I did all of the work myself under permit.

I bought an ammeter and looked at the amp draw for circuit with only one of the circuits drawing power and then looked at the load with everything drawing power. The range drew 31 amps with all 4 burners and the oven on (40 amp breaker). The fridge drew 0.3 amps by itself and 1.4 amps with everything on. The 2 counter top circuits drew 12.5 amps each with a hot pot on one circuit and the microwave on the other. The hot pot and microwave are both rated at 12.5 amps.
The only thing that stands out is the change in the fridge draw. I expected it to draw more than 0.3 amps by itself and don't know why it increased when other circuits were drawing power.
I think the next step is to have an electrician come in and take a look.
 
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Old 04-10-21, 09:19 PM
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I did all of the work myself under permit.

I bought an ammeter and looked at the amp draw for circuit with only one of the circuits drawing power and then looked at the load with everything drawing power. The range drew 31 amps with all 4 burners and the oven on (40 amp breaker). The fridge drew 0.3 amps by itself and 1.4 amps with everything on. The 2 counter top circuits drew 12.5 amps each with a hot pot on one circuit and the microwave on the other. The hot pot and microwave are both rated at 12.5 amps.
The only thing that stands out is the change in the fridge draw. I expected it to draw more than 0.3 amps by itself and don't know why it increased when other circuits were drawing power.
I think the next step is to have an electrician come in and take a look.
OK this makes sense now it sounds more like an open or loose neutral then, this could be anywhere the main sub panel or even the power companies side. Did you measure the voltage also when this is occurring?
One sure sign is one leg has higher or lower voltage then the other and dimming or brightening lights.
 
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Old 04-11-21, 04:38 PM
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I replaced the refrigerator arc fault breaker with a standard breaker to see if that will make a difference. the arc fault breaker had some discoloring on the neutral wire that looks like scorching. The wire is intact with no obvious nicks. It may have been touching a hot wire from the same or an adjacent breaker int he panel. I checked the wires and could not find any nicks in the insulation.


 
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Old 04-12-21, 06:52 PM
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Looks like ink that was used to print the information on the wire (AWG 12 type THHN, etc) does not look like scorching to me it would discolor the insulation brown if it was but I can't really see it form a picture.
 
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Old 04-13-21, 06:40 AM
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Another vote for a weak neutral connection. What to do.... I would put a high load device on the reefer recept. Space heater or hair dryer, with a voltmeter in parallel. Any circuit a multiwire?
 
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Old 04-13-21, 08:29 AM
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I'll look into a weak neutral connection. There are not any multiwire circuits. Thanks for the input.
 
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Old 04-13-21, 03:55 PM
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That is an odd mark on that wire. Does not look like it would be from the factory to me.
 
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Old 04-13-21, 04:59 PM
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The mark is more brown than black. The insulation is intact and smooth with no other indication of scorching. The black wire from the same circuit may have been touching the neutral wire where it is discolored.
 
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Old 04-13-21, 05:50 PM
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Brown makes me think that the wire was getting hot at that spot. Much hotter than another wire touching it unless that wire was also quite hot. I have seen many white wires discolored brown due to loose connection, but that is typically where the wire terminates to a device, breaker, or lug.
 
 

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