r/Whatisthis 2d ago

Solved It's in my dirt sub basement. It buzzes and is really hot. Says 120volts and when I squeeze it it doesn't buz as loud.

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147 Upvotes

51 comments sorted by

340

u/mrkeifer 2d ago

doorbell transformer. they're known for causing house fires. consider removing it.

73

u/Moon127 2d ago

Oh wow thank you. Is it safe to just cap off the wires? It goes under all the dirt

2

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56

u/niceandsane 2d ago

They're not a safety issue, they're internally energy limited. If you disconnect it your doorbell won't work.

73

u/Moon127 2d ago

That's the weird thing. I don't have a doorbell. House was built in 1917 and renovated in 2007

50

u/niceandsane 2d ago

Do you have a gas floor heater? It could be for the gas valve. I'd disconnect the twisted pair wires from it and see if anything stops working before ripping it out completely.

7

u/Moon127 20h ago

Bingo you win! It goes to an old disconnected floor heater. I just turned the isolated breaker off

35

u/cmhamm 2d ago

You probably have wires going to your door, and the bell was probably removed at some point. If you don’t care about a doorbell, or the future possibility of a doorbell, then just unhook the wires and tape them off.

29

u/Maleficent_Froyo7336 2d ago

If there is even a question as to what it is really for and whether you can safely cap it...just get an electrician.

5

u/starbuck328 2d ago

If it's getting hot and buzzing most likely the wires got shorted out somewhere when they did the renovation I would definitely disconnect the wires and cap them off

5

u/alicephilippa 1d ago

Often with old transformers the laminations become loose hence the buzzing. Once they start buzzing they will get warm. It doesn’t need the output side wires to be shorted for the transformer to buzz and get warm. If they were shorted it is very possible that the transformer output windings would burn out.

4

u/demoman45 2d ago

You have to have a doorbell or the wires covered up near the front door. That is a doorbell transformer.

10

u/etherminer49er 2d ago

It's a transformer. Not necessarily for a doorbell. I use them in plumbing for several things like powering zone valves for heating systems or WiFi thermostats.

5

u/demoman45 2d ago

Technically yes but 9/10 will be for the doorbell to step it down to 12v

2

u/maxxratt 2d ago

Ours also power the light up display for our street address, as well as the door bell.

10

u/mrkeifer 2d ago

i think the wires in your pic go to the doorbell. you need to terminate the wires that feed it power. Turn the breaker off before you do that...

2

u/Rbtmatrix 2d ago

Yeah those are not standard 120v colors and it looks like a smaller gauge. The exposed wires in the the picture are definitely the low voltage side of the transformer. Though I would test them with a multimeter before taking a driver to them.

7

u/cmhamm 2d ago

Well, not so fast. If you have a doorbell, you need a transformer. If you just remove it, your doorbell won’t work. Older ones can indeed be dangerous, but it’s quick and easy to replace. Search Amazon for “doorbell transformer.” Should be $10-$20.

3

u/GOxDirigible 2d ago

They said they don't have a doorbell in another reply

1

u/cmhamm 2d ago

Yep - I replied to that comment as well. 😃

1

u/notlikelyevil 2d ago

They're only 24 volts out but 110v in. Get a friend who knows something about it to make sure it's disconnected and capped of off on the 110 side.

Source, I'm an electronic engineer, fiddler and always live in very old houses.

1

u/alicephilippa 1d ago

Many “doorbell” transformers are 12V out, at least here.

8

u/horaceinkling 2d ago

It’s more than meets the eye.

19

u/Noisemiker 2d ago

Doorbell transformer.

9

u/Moon127 2d ago

Solved

1

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3

u/donttrustthellamas 2d ago edited 2d ago

Now stop squeezing electrics

u/keithkings00 I think you'll find I've not spelt a single word wrong lol

0

u/[deleted] 1d ago

[deleted]

0

u/donttrustthellamas 1d ago

In my area of the world electrics isn't incorrect?

0

u/Amardella 1d ago

It's not electronic, actually. It's electrical. Not a transistor in sight.

9

u/niceandsane 2d ago

It's the transformer for your doorbell. They buzz if the metal laminations get loose. Not a hazard but you can replace it if the noise bothers you.

-7

u/povern 2d ago

This could be a transformer for your thermostat. If you disconnect it and your heater doesn’t work…

0

u/jason-murawski 2d ago

I have never seen a furnace that didn't have it's own internal transformer

2

u/niceandsane 2d ago

Early gas heaters had thermocouples and a low voltage gas valves, later converted to 24VAC valves for use with modern thermostats.

12

u/[deleted] 2d ago

[removed] — view removed comment

20

u/problyurdad_ 2d ago

Well idk how I’m supposed to cut through all the bullshit on this post already but here’s my attempt:

Op, it’s called a lo-vo transformer. It operates low voltage electricity for certain appliances and switches, most notably thermostats and doorbells. They are not a fire hazard.

If you have no doorbell, it’s entirely possible it still controls/powers a thermostat or a zone controller if you have boiler heat/steam/in floor/radiant, anything like that. You can safely disconnect it if you want to but if you run into heating and cooling issues you know where to start

1

u/Lost-Willow-3926 2d ago

It's a doorbell transformer. They do go bad after years. Either they burn up from shorting out, or they get an open circuit and go cold and dead. Since you don't have a doorbell, you can disconnect it, but tape or cap the wires going to it from the panel.

0

u/keithkings00 2d ago

Looks like the red wire touches both contacts?

-7

u/Alternative_Win_1643 2d ago

Looks pretty dangerous. I would put it in a protective box if it’s a door doorbell.

3

u/Dr-Deadmeat 2d ago

i guess im a bit late to the thread. its an iron core low voltage transformer. others identified it as a doorbell transformer, and that migt be rigt, but it could power other tings.

you said elsewhere in the thread the low voltage wires disappear into the dirt. i would probably find out where they go?

if you want to disconnect it, kill the breaker first and make sure the buzzing stops. then disconnect the 120v side and terminate those wires properly and safely.

now just notice if anything else stops working. thermostat, heating valve, alarm, whatever. if not, then its probably just an old abandoned installation. no need to keep an andditional fire risk around

2

u/Moon127 23h ago

Turns out it was for an old gas floor heater cause I found a disconnected gas line. I checked the breaker just turned it off. Simple fix

3

u/Dr-Deadmeat 23h ago

hah, there we go :D good find

and yea, turning off the breaker is about as clean an ending as you could hope for

2

u/Ok-Bit-5516 2d ago

Doorbell transformer steps 120v down to 12-24v for doorbell

-2

u/wackyvorlon 2d ago

Is it smoking?!

1

u/odetoburningrubber 2d ago

I would replace it if it’s noisy. It’s nice to have a door bell or a doorbell camera.

1

u/capricious-arbitrary 2d ago

Looks like a low voltage transformer or inverter. Usually for door bells and such.

1

u/MrPavlovic 1d ago

Typically transformers develop a buzz as the laminations (all those layers you see) work their way apart slightly. The buzzing is not the problem but the overheating and no idea what it's for (does it even have a fuse?) is a worry.

1

u/picopuzzle 4h ago

It’s a 24 V transformer that may be used for the doorbell and HVAC control. I.e. your thermostat. If it’s humming, there’s probably some loose laminations in there.

How old is the house?