Doorbells, AFCI breakers

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Good morning everyone,
For new residential construction, do I need to have the doorbell on an AFCI breaker or does it even matter?

Thank you
Joe
 

480sparky

Senior Member
Location
Iowegia
Depends on where the transformer is located. If it's in a room that requires AFCI protection, then yes. If it's not, then no.
 

al hildenbrand

Senior Member
Location
Minnesota
Occupation
Electrical Contractor, Electrical Consultant, Electrical Engineer
The location of the 120 Volt 15 or 20 Amp outlet that supplies power to the doorbell system, that is, where the transformer is mounted, is the key. If the transformer is in one of the areas described in 210.12(A), then, yes. If the transformer is elswhere, then it is not required.

210.12 only applies to outlets on 120 Volt 15 or 20 Amp branch circuits.
 

Hv&Lv

Senior Member
Location
-
Occupation
Engineer/Technician
Good morning everyone,
For new residential construction, do I need to have the doorbell on an AFCI breaker or does it even matter?

Thank you
Joe

Where is the transformer? behind the bell, in the crawl space or basement? Maybe at the panel. That would be the deciding factor on afci protection IMO.
 

hurk27

Senior Member
Just to point out that an AFCI breaker would not protect the wiring after the transformer and is really not needed to, while here it is very common to place the transformer on the switch box for the furnace, I started installing them into a box behind the bell because it not a load allowed on the furnace circuit, but I despise having to find them in an attic and the heat of many attics can cause the thermo-fuse in the transformer windings to fail, another common place that makes the most sense is on a box right off the breaker panel, or if panel is surfaced mounted then in one of its K/O's, but at least here in Indiana we are not required to use AFCI so having it on one is a mute question here.
 

gndrod

Senior Member
Location
Ca and Wa
Good morning everyone,
For new residential construction, do I need to have the doorbell on an AFCI breaker or does it even matter?

Thank you
Joe

NEC 2008 cycle general purpose circuits require AFCI protection that includes a BC to the primary of the xfmr feeding the door bell.
 

kwired

Electron manager
Location
NE Nebraska
NEC 2008 cycle general purpose circuits require AFCI protection that includes a BC to the primary of the xfmr feeding the door bell.

Not necessarily. If the doorbell transformer is not on a circuit requiring AFCI or in a location where outlets are required to be protected by AFCI then there is no reason it has to be AFCI protected.

SABC's are out of the question as the transformer would not be allowed on those circuits,

It could be on a bathroom outlet circuit but the transformer would have to be located in the bathroom, it could also be connected to an unfinished basement circuit, a garage circuit or an outdoor circuit as long as the transformer is not located in a room where AFCI protection would be required.
 

gndrod

Senior Member
Location
Ca and Wa
Not necessarily. If the doorbell transformer is not on a circuit requiring AFCI or in a location where outlets are required to be protected by AFCI then there is no reason it has to be AFCI protected.

SABC's are out of the question as the transformer would not be allowed on those circuits,

It could be on a bathroom outlet circuit but the transformer would have to be located in the bathroom, it could also be connected to an unfinished basement circuit, a garage circuit or an outdoor circuit as long as the transformer is not located in a room where AFCI protection would be required.

I'll go half way on the 'not necessarily' from practical experience of running BC's throughout a dwelling. General purpose circuits was the caveat I used to not include GFCI circuits in outside, garage and unfinished basements. There are rare practical locations left to select a circuit for the xfmr primary that would be a BC that is not on an AFCI for new construction. A multifamily dwelling is a tough one to find a non-AFCI BC as an example.
 

kwired

Electron manager
Location
NE Nebraska
I'll go half way on the 'not necessarily' from practical experience of running BC's throughout a dwelling. General purpose circuits was the caveat I used to not include GFCI circuits in outside, garage and unfinished basements. There are rare practical locations left to select a circuit for the xfmr primary that would be a BC that is not on an AFCI for new construction. A multifamily dwelling is a tough one to find a non-AFCI BC as an example.

If you put the transformer at/near the panel you can easily put it on any circuit you wish. Unless you normally use GFCI breakers instead of GFCI receptacles it can easily go on the mentioned circuits without the transformer being on GFCI protected portion of a circuit.
 

kwired

Electron manager
Location
NE Nebraska
Not always. You can't use the bath, laundry or any SABCs.

That is why I said you can easily put it on any circuit you wish. Did not say it was acceptable to put it on any particular circuit. ;) I already mentioned a some of the circuits in a previous post that it can not be on.
 

George Stolz

Moderator
Staff member
Location
Windsor, CO NEC: 2017
Occupation
Service Manager
Let's take this up a notch. :)

I say that if I ran a 14-2 home run to a single gang box in a bedroom, installed a blank cover and the transformer on the cover, I still would not need an AFCI. Discuss. :D
 

kwired

Electron manager
Location
NE Nebraska
Let's take this up a notch. :)

I say that if I ran a 14-2 home run to a single gang box in a bedroom, installed a blank cover and the transformer on the cover, I still would not need an AFCI. Discuss. :D

I think we have addressed that already. If you put the transformer there it meets the definition of outlet. If it is in the bedroom all 15 and 20 amp 125 volt circuits supplying outlets in that room need afci. Put it on other than 15 or 20 amp 125 volt circuit and GFCI is not needed. How about a 240 volt primary for this transformer? Won't be as cheap as ones made specifically with doorbells in mind.
 
Just to point out that an AFCI breaker would not protect the wiring after the transformer and is really not needed to, while here it is very common to place the transformer on the switch box for the furnace, I started installing them into a box behind the bell because it not a load allowed on the furnace circuit, but I despise having to find them in an attic and the heat of many attics can cause the thermo-fuse in the transformer windings to fail, another common place that makes the most sense is on a box right off the breaker panel, or if panel is surfaced mounted then in one of its K/O's, but at least here in Indiana we are not required to use AFCI so having it on one is a mute question here.

Is this legal? I did this years ago by installing a double gang box for the doorbell, but was tagged for it so I changed the location to the furnace disconnect box.
 

al hildenbrand

Senior Member
Location
Minnesota
Occupation
Electrical Contractor, Electrical Consultant, Electrical Engineer
Let's take this up a notch. :)

I say that if I ran a 14-2 home run to a single gang box in a bedroom, installed a blank cover and the transformer on the cover, I still would not need an AFCI. Discuss. :D
:?

Interesting.

The doorbell system (transformer, class 2 wiring and door buttons) are included in the Article 100 Defintion of Premises Wiring (System).

The doorbell transformer is a power supply that does not have a Service Point (again, Art.100) . . . so, by:
This includes . . . (b) wiring from and including the power source to the outlets where there is no service point.
. . . so, the transformer is included in the Premises Wiring (System). Doesn't sound like it can be at an outlet.

That pushes the Outlet all the way to the chime (and the buttons - if you think like I do ;))
 

kwired

Electron manager
Location
NE Nebraska
:?

Interesting.

The doorbell system (transformer, class 2 wiring and door buttons) are included in the Article 100 Defintion of Premises Wiring (System).

The doorbell transformer is a power supply that does not have a Service Point (again, Art.100) . . . so, by: . . . so, the transformer is included in the Premises Wiring (System). Doesn't sound like it can be at an outlet.

That pushes the Outlet all the way to the chime (and the buttons - if you think like I do ;))

I'm starting to think that you are right about this.

Art 100 definition of outlet: A point on the wiring system at which current is taken to supply utilization equipment.

The transformer is not utilization equipment the chime is.

The chime is not 15 or 20 amp 125 volts.
 
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