Electrical questions

[Wade Lippman]

My son bought a house built in 1950. I am trying to get a nest doorbell working. His wires are cloth covered. Is that normal for 1950. He has two transformers. One is 16.7v for the door bell. What could the 25v be for. He has a defunct intercom and defunct heat sensors. Could it be for either of them. Finally it looks like the chime is set up for two doorbells but there's no trace of the second one. Could it be anything else.

In the unlikely event anyone knows about nest doorbells... He installed it and it worked for two years except that the chime didn't ring but their nest mini did so it was okay. One night the chime started buzzing loudly and they disconnected it. They bought a new chime but they couldn't get anything to work. I find 16.7v at the doorbell a green light is on the nest and shorting the wires makes the chime ring but nest doesn't do anything. The instructions say the voltage is inadequate but I think that is wrong. I think the nest
Is simply broken. Any advice.

[Bill George]

Set up for 2 doorbells, like wires connected and heading off somewhere? What is the voltage rating of the Nest?

So the wired version is 16 to 24 volts ac and there is a battery powered version.
Which so you have?

[Leo Graywacz]

24v transformers are used for thermostats connected to heat. Not saying that's what this one is for.

[Lee Schierer]

Cloth covered wiring was the norm in 1950. The actual insulation of the wires was rubber which can harden with age. Moving the wires around can crack or disintegrate the insulation.

[George Yetka]

I had a bear of a time with Ring doorbell. Getting it to work, getting it to work with the house doorbell chime. I installed it fine, but had to replace the transformer once I found it took me hours as I didnt install it. then after a week it started ringing itself between 1-2 am every night. I disconnected it at 2 am one night. Next weekend I replaced the transformer again as well as the door chime. worked fine for 3 days then started the early morning ringing. I disconnected the doorbell and chucked it. a year later when I calmed down I had got a new one It has been wired and fine for 3 years now.

The second tranformer could be HVAC those are usually built into a furnace but boilers sometimes dont have a transformer in them, This transformer I would expect to be buy either heat source. It could also be security or intercom

[Bill Dufour]

Our old house was built in 1949. Rubber insulated wires covered in tarred cloth. Real 2x4's in the wall so you need to add 1/2 shims to modern "2x4"s. The walls are 1/2" button board then 1/2" hard coat plaster. This blocks stud sensors and wifi signals. No modern "old work" electrical boxes with mounting clips are deep enough to work. I got good at screwing a box to a stud from inside. No insulation as built.
Bill D.

[Lee Schierer]

No modern "old work" electrical boxes with mounting clips are deep enough to work. I got good at screwing a box to a stud from inside. No insulation as built.
Bill D.

Have you tried the Carlon 1-Gang 20 cu. in. PVC Old Work Electrical Switch and Outlet Box They seem to work just fine on our blue board and plaster walls that are at least 5/8" thick.

[Bill Dufour]

The walls in that house are one inch thick so only 5/8" is too short.
Also good luck telling white from black 70 year old insulation. When I did any work inside a box I slipped heat shrink over the exposed insulation for extra safety. No heating. And I made sure no conductors touched anything so they had a air gap beyond the tarred cloth.
Bill D

[Tom M King]

I like the heavy old work boxes. I've used them in old house plaster walls before, but I don't remember how thick the plaster and lath was. I've used these in new houses for a long time, or any new work I do. I rough in the wires only, and when I put something on the wall, like rarely sheetrock, I cut the opening for the box, install the box in whatever the wall finish is, and run a bead of construction adhesive around the parameter on the inside. I put the wires in the box as we put whatever it is on the wall.

I've never had an inspector complain about this, and even had one say he was going to do his house like this. I've never had any trouble with one of them, and the wall is not torn up around the box. I really don't like oversized cover plates.

These cost a bit more, but they're a lot more substantial than the flexible ones.

https://www.homedepot.com/p/Carlon-1...118R/100154882

[Wade Lippman]

That could be. He has a heat only thermostat. He has a boiler, which is not anything I am familiar with.

[Wade Lippman]

24v transformers are used for thermostats connected to heat. Not saying that's what this one is for.

That could be. He has steam heat with a heat only thermostat. I will have him check to make sure I didn't ruin anything.

[Wade Lippman]

Cloth covered wiring was the norm in 1950. The actual insulation of the wires was rubber which can harden with age. Moving the wires around can crack or disintegrate the insulation.

I didn't see any rubber, but maybe it all cracked off. It was under the cloth I presume?

[Wade Lippman]

Set up for 2 doorbells, like wires connected and heading off somewhere? What is the voltage rating of the Nest?

So the wired version is 16 to 24 volts ac and there is a battery powered version.
Which so you have?

There were 4 cables coming into the chime. One was from the transformer, one was to the door bell. The third I suspect was to a second doorbell, but there is no trace of where it might have been. The fourth was newer and "might" have gone to intercom terminals on the chime, though nothing was attached. I have no idea what a chime had to do with an intercom, but that is what it said.

It is the wired doorbell.

[Tom M King]

I would run new everything, including wire. Just don't worry about the old stuff.

[Jim Becker]

I had the same thought that Tom just expressed when I first read this thread. While it can be a pain, rewiring with new wire gets around any difficult to determine routing for old, old stuff.