AFCI breaker - furnace motor keeps tripping it

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pdxsk

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My home has a natural gas furnace in the daylight basement. The room the furnace is in, is not a bedroom or otherwise occupied. We store items in the room (at least six feet away from the furnace).

The home was built in 2018. We had some electrical work done this year (2022). For that inspection, we happened to get the same State of WA L&I electrical inspector for our work, as who originally inspected the home in 2018.

According to him, some of the AFCI breakers were switched out for standard breakers namely, the furnace circuit breaker. I happen to know the original homeowner (who is a close family member to me), and he said "yes, we changed them out as they kept tripping. My wife's mixer in the kitchen would trip...even the brand new furnace would trip the AFCI, so I changed them to standard breakers".

Long story short...I had an AFCI breaker put in for the furnace at the main panel. And now...every few days, if not more often...the AFCI breaker trips.

The inspector won't pass my new electrical work until he sees an AFCI on my furnace circuit breaker, which I would have thought was grandfathered...but he says it was swapped since he inspected in 2018. (and he is correct)

I'm at a loss of what to do. I suppose I can have him inspect with the AFCI, and then change the breaker back to standard...like the prior homeowner??

Any thoughts, would be appreciated.
 
Thank you for the reply. I didn't read close about DIY questions...!

I will check my local jurisdiction (county) and see if they have any requirements different than the NEC standard. I appreciate it!
 
To keep the new AFCIs you will need to get an electrician out to check all the possibilities that could be. Your new breakers may have a diagnostic built in that the old didn't. Check those out.

I would not think your furnace would need an AFCI if hardwired, wherever the location.

The kitchen receptacle, IDK which code cycle you were under. New mixer is sometimes the answer for that if it's an older one.

Kitchen receptacles should be GFCI protected at minimum.

Otherwise you know the solution.
 
I believe most furnaces today use a hot surface ignition. But if your furnace has spark ignition, then it wouldn't surprise me if it triggers an AFCI breaker.
 
The need for AFCI depends in room type, and it applies to "outlets" which means receptacles, light fixtures, and hard wired access points need to be on an AFCI circuit. Your home was probably inspected under the 2017 code. I see no reason why you can't remove something that exceeded code at the time. I don't have a copy of it, but the 2014 covers the following areas (and I think 2017 and even 2020 are the same):

210.12(A) Dwelling Units. All 120-volt, single-phase, 15- and 20-ampere branch circuits supplying outlets or devices installed in dwelling unit kitchens, family rooms, dining rooms, living rooms, parlors, libraries, dens, bedrooms, sunrooms, recreation rooms, closets, hallways, laundry areas,
or similar rooms or areas shall be protected...

Is the furnace in one of these room designations? I not, I question the inspector for the requirement of the AFCI. Whether it was AFCI before is not relevant. Closet could be a it if its in a utility closet or if the laundry is close to the furnace and there are no walls separating the laundry. The only NEC defined term for closets is "clothes closet", but this only says closet which may be wider in scope. I see nothing in the state WAC rules modifying the NEC rules for AFCI circuits. Since you said an L&I inspector, I assume you are not in one of the areas that has its own electrical additions (e.g. Seattle), as you'd need to see those local rules to know if you are not meeting some requirement.

If all else fails, or you are in one of the areas that requires AFCI, just put in the AFCI when the inspector is there, and take it out when it trips again after he leaves. Spending some time on learning why the AFCI trips could be useful (most of the newer ones have lights that blink a certain number of time telling you why it tripped, and if its a current leak there may be a wiring error). What is the brand of panel and AFCI breaker that is being used?
 
Finally, is this furnace GFCI protected? That would most likely be a requirement in an unfinished basement. If you had a GFCI breaker, and changed it to non-GFCI, then you have a problem. Inspector could have confused AFCI with GFCI. New GFCI requirements have caused headaches for many, especially with HVAC systems. The state delayed some of the HVAC GFCI requirements (e.g. the outside compressor unit is now required to be GFCI protected, but so many trip them they delayed implementation). Most people don't replace their HVAC in a few years, so after they lift the exemption and new equipment is out that doesn't trip things you're in a pickle if you don't want to buy a new furnace.
 
suemarkp said:
Finally, is this furnace GFCI protected? That would most likely be a requirement in an unfinished basement. If you had a GFCI breaker, and changed it to non-GFCI, then you have a problem. Inspector could have confused AFCI with GFCI. New GFCI requirements have caused headaches for many, especially with HVAC systems. The state delayed some of the HVAC GFCI requirements (e.g. the outside compressor unit is now required to be GFCI protected, but so many trip them they delayed implementation). Most people don't replace their HVAC in a few years, so after they lift the exemption and new equipment is out that doesn't trip things you're in a pickle if you don't want to buy a new furnace.
Click to expand...

Are you sure? I thought only receptacle outlets in unfinished basements required GFCI protection.
 
I think I'm mis-remembering... An outside HVAC unit hard wired needs GFCI. Most other things inside are receptacles only. So a hard wired furnace in an area needing GFCI typically wouldn't need to be GFCI protected. Even under 2020 code.

I think AFCI could still apply, as it goes to outlets and not receptacle outlets. The type of room its in will determine if AFCI applies. All we know about this one is basement and nothing further like if in a closet room.
 
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retirede said:
Are you sure? I thought only receptacle outlets in unfinished basements required GFCI protection.
Click to expand...
2020 changed to all receptacles in basements whether in finished areas or not.

This shouldn't matter here unless this furnace is cord and plug connected for some reason.
 
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