AFCI Tripping when dryer door is opened

Status
Not open for further replies.

Little Bill

Moderator
Staff member
Location
Tennessee NEC:2017
Occupation
Electrician
Before telling customer to call POCO I would at least place temporary unbalanced load to see how neutral voltage responds. If not good response more fuel for your theory that they might have a problem. But here I usually will be one calling POCO and will likely be there when they show up to check out the problem, but here we typically know the POCO guys personally anyway, and even have personal mobile phone numbers for at least some of the supervisors and can bypass the main office clerk that will only pass a message on. Can't have that in many cases in large cities.
Did you mean for this post to go here? It doesn't seem to fit.
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
I was told by another EC friend that if the system is bond at different points it will cause AFCI breakers to trip.


“ shoot low boys their riding shetland ponies”
This is a possibility if the breaker is a dual function AFCI/GFCI and it is the GF element that is tripping. You should always use the breaker diagnostic procedure to see why it tripped.
 

Archer973

Member
Location
Washington
Occupation
Retired Electrical Engineer
I am building new house and have been experiencing this problem with one of the several AFCI breakers, the one for the lights in the guest bath. I installed a combination light/heat/exhaust unit in the ceiling. The heater required a separate 12 A supply. So I ran two circuits insuring both were the same phase so I did not 240 Vac at the unit (required by code). Since the circuits were the same phase, I did not see a problem with wiring both the neutrals together.

We started experiencing the problem of this breaker being tripped whenever a high amperage motor was started on any circuit in the house or shop. I won't go into details of all the hours I spent troubleshooting this problem before googling and finding this and several other forum discussions. I didn't find an answer anywhere, but solved the problem today when I decided to separate the neutrals and fixing the issue.

I hope this info will be helpful to someone.
 

ptonsparky

Senior Member
Location
NE (9.06 miles @5.9 Degrees from Winged Horses)
Occupation
Electrical Contractor
I am building new house and have been experiencing this problem with one of the several AFCI breakers, the one for the lights in the guest bath. I installed a combination light/heat/exhaust unit in the ceiling. The heater required a separate 12 A supply. So I ran two circuits insuring both were the same phase so I did not 240 Vac at the unit (required by code). Since the circuits were the same phase, I did not see a problem with wiring both the neutrals together.

We started experiencing the problem of this breaker being tripped whenever a high amperage motor was started on any circuit in the house or shop. I won't go into details of all the hours I spent troubleshooting this problem before googling and finding this and several other forum discussions. I didn't find an answer anywhere, but solved the problem today when I decided to separate the neutrals and fixing the issue.

I hope this info will be helpful to someone.
Shared or incorrectly paired neutrals have been an AFCI issue since day one. Most had GFCI detection built in.
 

kwired

Electron manager
Location
NE Nebraska
I am building new house and have been experiencing this problem with one of the several AFCI breakers, the one for the lights in the guest bath. I installed a combination light/heat/exhaust unit in the ceiling. The heater required a separate 12 A supply. So I ran two circuits insuring both were the same phase so I did not 240 Vac at the unit (required by code). Since the circuits were the same phase, I did not see a problem with wiring both the neutrals together.

We started experiencing the problem of this breaker being tripped whenever a high amperage motor was started on any circuit in the house or shop. I won't go into details of all the hours I spent troubleshooting this problem before googling and finding this and several other forum discussions. I didn't find an answer anywhere, but solved the problem today when I decided to separate the neutrals and fixing the issue.

I hope this info will be helpful to someone.
Bath doesn't need to be on AFCI (so far).

Single 20 amp circuit to supply such heat/vent/lights is normally sufficient. The blower motor(s) are usually less than an amp maybe amp and half on some and the light is less than an amp if LED but wasn't ever much more when incandescent.

If you do have AFCO protection on either or both circuits you mentioned you don't want interconnections between neutrals or it is asking for AFCI tripping issues.
 

retirede

Senior Member
Location
Illinois
If you do have AFCI protection on either or both circuits you mentioned you don't want interconnections between neutrals or it is asking for AFCI tripping issues.

Wouldn’t paralleling the neutrals be a code violation in and of itself?

Maybe not if they originate on individual breakers….
 

ramsy

Owner/Operator
Location
LA basin, CA
Occupation
Service Electrician 2017 NEC
Wouldn’t paralleling the neutrals be a code violation in and of itself?
Yes NEC 200.4, but no inspector can detect it to request the correction.

I can see why AFCI and GFCI breakers may be loathed for forcing unforeseeable complications like this, if not billable under most competitive-bid contracts, much less solved by unskilled laborers.
 

kwired

Electron manager
Location
NE Nebraska
Yes NEC 200.4, but no inspector can detect it to request the correction.

I can see why AFCI and GFCI breakers may be loathed for forcing unforeseeable complications like this, if not billable under most competitive-bid contracts, much less solved by unskilled laborers.
The interconnection of neutrals from different circuits is still not code, but you usually get away with not knowing about it unless you have GFCI or AFCI on either circuit involved.

Those fan/light/heater units generally do have separate neutral terminations for each component and can easily be separated if not all on same circuit.
 

retirede

Senior Member
Location
Illinois
Yes NEC 200.4, but no inspector can detect it to request the correction.

Agreed, the reason I mentioned it was because it seemed a bit concerning that the forum member who resurrected this thread seems to think it was OK simply because “both circuits were on the same phase”!
 

Archer973

Member
Location
Washington
Occupation
Retired Electrical Engineer
Bath doesn't need to be on AFCI (so far).

Single 20 amp circuit to supply such heat/vent/lights is normally sufficient. The blower motor(s) are usually less than an amp maybe amp and half on some and the light is less than an amp if LED but wasn't ever much more when incandescent.

If you do have AFCO protection on either or both circuits you mentioned you don't want interconnections between neutrals or it is asking for AFCI tripping issues.
Hi kwired. Based on your response I see a mistake in my post. I meant 20 A for that heater feed, don't know why I said 12. I should also have explained the feed for the bathroom light also feeds the hall and guest bedroom lights which is why it is an AFCI circuit. Also, the manufacturer's installation instructions required a separate feed for the heater. Thanks for your reply.
 
Last edited:

Archer973

Member
Location
Washington
Occupation
Retired Electrical Engineer
To all who commented. Thank you for your responses, even those not expressly written to me. I have learned a few things, but after checking my emails a few minutes ago, I find that this site is not intended for do it yourselfers, which is what I am. So, I do appreciate what was said. Feel free to delete my posts and remove me from the forum. Best of luck to each of you.
 

retirede

Senior Member
Location
Illinois
To all who commented. Thank you for your responses, even those not expressly written to me. I have learned a few things, but after checking my emails a few minutes ago, I find that this site is not intended for do it yourselfers, which is what I am. So, I do appreciate what was said. Feel free to delete my posts and remove me from the forum. Best of luck to each of you.

As an EE, you are allowed to participate here, but need to limit contributions to your area of expertise.
 

curt swartz

Electrical Contractor - San Jose, CA
Location
San Jose, CA
Occupation
Electrical Contractor
While we are not allowed to help DIY's. The requirement for the dedicated circuit if for the entire unit (heat/fan/light/nightlight) You are not supposed to just feed the heat portion with the different circuit.
 
Status
Not open for further replies.
Top