I have a question that relates to a doorbell install that you folks have been helping me with, along with another transformer install that I have to do for a AC system. The transformer that had been spec'd out a couple of years ago for the AC system called for a JBOX with a extension to give it depth and the transformer would mount directly inside of the box with the low voltage terminals sticking out, visible and easy to work on. I want to find the same setup for my doorbell install as the device will be in a home run closet that is drywalled! It is impractical to rip open the wall to install on the side of a JBOX. It is easier to just cut in a retro box that I can dedicate to the transformer and then pull Romex or THNN from a nearby outlet. What type of transformer fits inside of a JBOX and what size jbox do I get. I know that I have seen applications in the past, where the transformer is sticking right out of the box. Can someone help me with this. I am confused. If I was given bad info re the AC transformer that it will be a pain to rip out that box and reposition.
Help With Transformer Install
Sep 14, 2009
6 Replies
One method would be to install an extension ring on an existing box. Install the transformer in a KO on the exposed extension ring.
*I had the same thought. They make a four inch square box that will mount onto a in-wall outlet box. You will need to go to a electric supply company to get it. Check out the Raco/Hubbell web site to get a part number. One thing though is if you would be mounting this onto a plastic box you would need to connect a ground wire onto the metal box using a G clip.
Most of the transformers that I see and install for doorbells and furnace control are mounted on the exterior of electrical boxes with the line voltage leads going into a knockout. The only exception is factory installed transformers that are mounted directly inside of equipment.
I've never seen what you describe. The garden variety doorbell transformer has either a male 1/2" threaded nipple with the line voltage wires coming through, or a screw down fitting that also fits into a 1/2" knockout. Either way, the transformer sits on the surface. If you've mounted a large panel in the closet, for what was going to be your intercom interface, you could probably fit a box and transformer inside it. Another possibility, similar to what Bud suggested, is to cut in a switch box and install a blank plate on it, with a 1/2" knockout in the plate, and mount the transformer to it.
I want to find the same setup for my doorbell install as the device
I thought I knew a lot of stuff, but I never encountered the term "Home run closet".
Goggle and Wiki don't help much.
I gather it's a closet, but what does "Home Run" signify.
Jeff
Electricians sometimes call the cable that goes from the panel to the first outlet, a home run. The OP was installing an intercom system, and ran each line from a station, back to this closet, where the control panel was to be located, so he's calling the lines home runs, and the closet is where the home runs terminate. Personally, I would have called it a dugout.
Where each wire goes out from the panel (or whatever) to a single jack or other termination, not daisy-chained.
MikeB
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