doorbell transformer

rllevine

Member
Location
Alameda, CA
Can a doorbell transformer live inside of a J-box?

Typically, a doorbell xmer lives in a crawl space and is connected to a J-box through the 1/2"KO, with the xmer outside the box. In this application, the customer wants to add a doorbell and there is no crawl space below. There is room in the 3-gang switch box at the front door, right behind where the push button will go. I'd like to keep the xmer in that box (there is room), but is this legal? Are there heat issues with the xmer that would preclude me from keeping it enclosed in the box with a couple of switches?
 

hbiss

EC, Westchester, New York NEC: 2014
Location
Hawthorne, New York NEC: 2014
Occupation
EC
A bell transformer is not designed to be installed in a box. Further, the low voltage CL2 wiring can't be in the same box with the line voltage conductors.

What I have always done is use a "wall wart" transformer plugged into a convenient receptacle, then run CL2 wiring to either the chime or pushbutton. You don't mention how you are running the wire from the push button to the chime or doorbell.

-Hal
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
You don't mention how you are running the wire from the push button to the chime or doorbell.
Agreed. Knowing that would help us help you.

There are doorbells that run on batteries, which get practically shelf life, as well as wireless buttons.
 

David Castor

Senior Member
Location
Washington, USA
Occupation
Electrical Engineer
In the houses I have lived in, the transformer has always been mounted to a drilled out cover plate high up in a closet. I wouldn't want one in a crawl space but maybe that's just me.
 

curt swartz

Electrical Contractor - San Jose, CA
Location
San Jose, CA
Occupation
Electrical Contractor
People still wire doorbells?:unsure:
Not always for chines but most clients want power for a doorbell camera. Ring, Nest , Ubiquity, etc.

In my area the standard location for the transformer has been the gas furnace disconnect switch box. Now that heat pumps are becoming the norm we install a receptacle somewhere near the front door, often the coat closet then use a plug in 16.5V 40VA transformer.
 

marmathsen

Senior Member
Location
Seattle, Wa ...ish
Occupation
Electrical Contractor
This looks interesting. Recessed transformer and chime combination. Does anyone have experience with Nicor brand products?
43acf2a9fc351b7b8ae92fbdd77e5e5b.jpg


Rob G - Seattle
 

marmathsen

Senior Member
Location
Seattle, Wa ...ish
Occupation
Electrical Contractor
It does beg the question, What is the difference between a lighting transformer like an LET60 that I've installed in junction boxes for decades, and a doorbell transformer? Or is it more that the wiring required to share a junction box with the 120V conductors wouldn't also work with the doorbell button and chime? Thus there's no market for an in-box transformer?
49ee9dae8dfcc9f272201c6b63704da5.jpg


Rob G - Seattle
 

tthh

Senior Member
Location
Denver
Occupation
Retired Engineer
Look for where you can drag the doorbell wiring to...if you can get it into the attic or where the furnace is or water heater or someplace like that, install a box there with the transformer hanging off it.
 

hbiss

EC, Westchester, New York NEC: 2014
Location
Hawthorne, New York NEC: 2014
Occupation
EC
Broan/Nutone C915 was designed to occupy a single gang box (120V inside the box, LV outside the box), but it was discontinued. I'm surprised nobody else makes a doorbell transformer for use in a junction box.


Cheers, Wayne

I remembered that and looked for it for him. Guess that's why I couldn't find it.

-Hal
 

winnie

Senior Member
Location
Springfield, MA, USA
Occupation
Electric motor research
If you are going basic, use wireless. It's cheap and it works.

If you are going fancy, run cat 5 and use power over ethernet for your doorbell/security camera/YouTube server.

Too many people use Wi-Fi based security systems, so thieves are jamming Wi-Fi before entering homes.

Jon
 

PaulMmn

Senior Member
Location
Union, KY, USA
Occupation
EIT - Engineer in Training, Lafayette College
If you are going basic, use wireless. It's cheap and it works.

If you are going fancy, run cat 5 and use power over ethernet for your doorbell/security camera/YouTube server.

Too many people use Wi-Fi based security systems, so thieves are jamming Wi-Fi before entering homes.

Jon
They also use WIFI for their house-wide internet. Then complain about slow speed!
 

Jpflex

Electrician big leagues
Location
Victorville
Occupation
Electrician commercial and residential
A bell transformer is not designed to be installed in a box. Further, the low voltage CL2 wiring can't be in the same box with the line voltage conductors.

What I have always done is use a "wall wart" transformer plugged into a convenient receptacle, then run CL2 wiring to either the chime or pushbutton. You don't mention how you are running the wire from the push button to the chime or doorbell.

-Hal
I was going to say that the transformer might have a better chance “living” if the box is not sealed and it has air to breath or there is someone on sight qualified to feed it daily.


Other than that I have only encountered a code that requires circuits over 1,000 volts to be separated from circuits under 1,000 volts with a partition or vault.

Is the transformer 120/24 volts 1kVA or less? Any live parts on xformer?
 

gene6

Senior Member
Location
NY
Occupation
Electrician
People still wire doorbells?:unsure:
Oh man its been a year of doorbell drama, we started a subdivision about this time last year, the model homes all had wired doorbells with decorative buttons, all 4 different plans have doorbells on the plans. We forgot or omitted the doorbells in about the first 6 production homes and the realtor flipped her lid said she cant sell a home without a doorbell.
We put in wireless ones for those 6
then it started the callbacks;
One of the new owners wanted to put in a wired doorbell camera and insisted there is supposed to be wiring in the walls for it.
Then another callback one of the wifi ones was ringing the wrong house.
Then another callback battery dead ..
I will say the wired ones do have a nicer 'chime', and the wireless one we used looked overly cheap.
 

tthh

Senior Member
Location
Denver
Occupation
Retired Engineer
I just never do anything wireless that can easily done wired. It makes no sense to go wireless and cause all the headaches that may follow for me or the owner or next guy debugging the problem.
 
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