Door bell transformer

[Stevenfyeager]

I've seen doorbell transformers in homes in various locations, mounted outside of service panels, laying inside of service panels, etc. I usually mount them on a metal box in an attic. What if there is no attic available on a job? Where can I mount it in a house (kitchen remodeling area) and be code compliant? (I have to replace the old one that was just mounted and exposed on a wall)
Thank you.

 

[1964element]

Furnace disconnect

Sent from my E6782 using Tapatalk

 

[mopowr steve]

I usually mount mine on the side of the panel.
I don't think it's healthy to ever put a transformer in the attic. It may even not be listed to do so.
In rare instances I have mounted to a handy box cover with KO on a box that was on a wall.

 

[Dennis Alwon]

I have seen them in clothes closets close to the header of the door. I usually install them in crawl spaces

 

[Bill Annett]

Good Morning,

Mopowr Steve, I think you are correct about the listing. It has been a while since I installed a door bell transformer but I do remember that the paper work that came with them stated that you were not allowed to install the transformer in an attic.

 

[al hildenbrand]

Given that you are changing the doorbell transformer mounting location in an existing dwelling, I'd look for a 1/2" KO in an exposed metal box (or retrofit a metal box) in a location that steers clear of AFCI requirements. No sense in complicating the modification of an existing circuit.

 

[kwired]

Given that you are changing the doorbell transformer mounting location in an existing dwelling, I'd look for a 1/2" KO in an exposed metal box (or retrofit a metal box) in a location that steers clear of AFCI requirements. No sense in complicating the modification of an existing circuit.

Aren't you adding an additional outlet to the circuit though? May only be 10 or 15 VA but is an additional outlet, not a replacement outlet.

 

[al hildenbrand]

Aren't you adding an additional outlet to the circuit though? May only be 10 or 15 VA but is an additional outlet, not a replacement outlet.

My point is: Don't pick a location for the transformer that is described in the list of rooms and areas in 210.12(A). . . and, the OP's profile says he's under the 2011 NEC.

Kwired, you raise an interesting twist in the "what is an outlet?" scenario.

Say I have a pull chain lampholder mounted on a 4" steel octagon box in the furnace compartment. The interior of the furnace compartment walls and ceiling are open wood framing.

The assembly of the octagon box / lampholder is the very definition of Lighting Outlet. A Lighting Outlet is an Outlet. . . . If I attach a doorbell transformer to the Lighting Outlet assembly and hard wire the primary side of the transformer to the branch circuit conductors, am I creating an additional Outlet or merely connecting a piece of equipment to the existing Outlet?

Or, to ask it slightly differently, where, in a Lighting Outlet, does the Outlet exist?

 

[kwired]

My point is: Don't pick a location for the transformer that is described in the list of rooms and areas in 210.12(A). . . and, the OP's profile says he's under the 2011 NEC.

Kwired, you raise an interesting twist in the "what is an outlet?" scenario.

Say I have a pull chain lampholder mounted on a 4" steel octagon box in the furnace compartment. The interior of the furnace compartment walls and ceiling are open wood framing.

The assembly of the octagon box / lampholder is the very definition of Lighting Outlet. A Lighting Outlet is an Outlet. . . . If I attach a doorbell transformer to the Lighting Outlet assembly and hard wire the primary side of the transformer to the branch circuit conductors, am I creating an additional Outlet or merely connecting a piece of equipment to the existing Outlet?

Or, to ask it slightly differently, where, in a Lighting Outlet, does the Outlet exist?

You are supplying an additional load no matter how you look at it.

If you put a short nipple between the lighting outlet and another box, then install the transformer on the second box, you still are supplying the same loads, but are more clearly distinguishing them.

Add: if you ran wiring from that lighting outlet box to an additional receptacle outlet whether 2 inches away or 100 feet away - I don't think anyone questions you have added an additional outlet.

 

[al hildenbrand]

You are supplying an additional load no matter how you look at it.

I totally agree with this.

But, to keep the question narrow, I want to consider the situation as an existing lampholder / steel octagon box assembly rather than adding an additional box beside or close by.

So, if supplying additional load is a deciding factor, would putting in a higher wattage lamp in the pull chain lampholder mean the Outlet is "new" or "modified"?

 

[kwired]

I totally agree with this.

But, to keep the question narrow, I want to consider the situation as an existing lampholder / steel octagon box assembly rather than adding an additional box beside or close by.

So, if supplying additional load is a deciding factor, would putting in a higher wattage lamp in the pull chain lampholder mean the Outlet is "new" or "modified"?

My thought wasn't so much adding more net load being a factor as much as the fact you are adding a completely different load.

Replace a 60 watt incandescent in the pull chain lampholder with a 28 watt compact fluorescent - you reduced electrical load, gained more light output, kept same lighting outlet.

Add a doorbell transformer and you introduced another load and another outlet. That outlet may or may not be at the transformer - the door chime may be the outlet even though it is on the secndary side of that transformer?

JMO.

 

[al hildenbrand]

My thought wasn't so much adding more net load being a factor as much as the fact you are adding a completely different load.

Put a "Y" lampholder adapter into the existing pullchain lampholder and add a screw in noise maker (or a second bulb) then one is adding a completely different load.

"A point on the wiring system at which current is taken to supply utilization equipment".

The transformer, or the second lamp seem to be using the same Outlet, to me.

 

[GoldDigger]

IMHO the outlet is not at the transformer location in any case. It is where the doorbell is located and arguably where a lighted (or unlighted?) push button is located. In which case you have certainly extended the circuit if the transformer is in a new location.

I do not generally consider a transformer to be utilization equipment, whether it is a power transformer or a doorbell transformer.

 

[al hildenbrand]

I do not generally consider a transformer to be utilization equipment, whether it is a power transformer or a doorbell transformer.

Real world transformers have hysteresis and resistance losses whether a load is supplied off the transformer or not.

How do we know "how much" of a Volt Amp loss one is allowed before an apparatus is a load in its own right, and therefore utilization equipment?

 

[GoldDigger]

So you would call the primary side connection of a transformer that implements an SDS an outlet?

 

[kwired]

IMHO the outlet is not at the transformer location in any case. It is where the doorbell is located and arguably where a lighted (or unlighted?) push button is located. In which case you have certainly extended the circuit if the transformer is in a new location.

I do not generally consider a transformer to be utilization equipment, whether it is a power transformer or a doorbell transformer.

And my initial response was mostly about AFCI requirements - so if the existing lighting outlet is not AFCI protected but is in an area where AFCI protection is required does this new outlet (I still think a new outlet was created somewhere) need AFCI protection? Now complicate that with the fact that if the outlet is at the door chime itself it is no longer a 120 volt circuit anymore at that point.

I do not think the transformer itself is utilization equipment but the doorbell chime is.

 

[al hildenbrand]

So you would call the primary side connection of a transformer that implements an SDS an outlet?

Your question turns out and away from a residential doorbell transformer. My hypothetical question involves a pull chain lampholder on a 4" steel octagon box in a dwelling to which a standard residential doorbell transformer is installed in a 1/2" K.O.

If the lampholder has an LED "night light" of 1/4 Watt threaded into the Edison screw shell socket, the assembly is a Lighting Outlet with a load installed.

Arguably, the no-load doorbell transformer loss, when energized by the branch circuit, will be in the neighborhood of 1/4 VA, and may be a skosh more. . .

Utilization Equipment among other things, utilizes electric energy for electronic purpose, which, in this case, is the transformation of one voltage to another.

Remember, this doesn't have to be an iron core transformer, the transformer might also be electronic.