26 votes

Doorbell transformer is this it?

As indicated by Ecnerwal the picture you show is an old style telephone line hookup. When you go looking around for your doorbell transformer it may look like one of these: Mounted on cover of an ...
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  • 61.3k
25 votes
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Do travel voltage transformers really not have grounding?

All this stuff is cheap Cheese junk You describe a genre of travel transformers, not just a specific one... but who's kidding who? The "genre" you're talking about is "the infinite ...
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24 votes
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How to get 24V from this transformer

The arrows point to the screws that will give a specific voltage and amps. For 24 volts at 20VA you use the right and left screws. Centre screw is left empty/unused. For 16 volts at 10VA you use the ...
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  • 5,761
20 votes
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Why bother referencing neutral to ground in residential transformer?

I know you're looking for a "tweet" of an answer, a simplistic reason "Oh, it's this". There's actually a lot to it. It's not an ideology, it's hard empirical data culled from a ...
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18 votes

Doorbell transformer is this it?

Nope. That's a phone line terminal block. Old school. May have rudimentary surge supression built in. The heavy black wire is drop cable (from the pole to your house) It's not your doorbell ...
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  • 134k
14 votes
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What is this thing on my garage wall?

Transformer. Probably for doorbell, possibly for hard-wired controls for garage door opener. The "string" is fabric-insulated low-voltage wire, which was commonly used for that purpose.
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  • 16k
14 votes

In wiring a doorbell, what is an alternative to using a transformer?

The answer is NO. All wired doorbells must be low voltage by NEC. You can find chimes with the transformer in the chime box, or mounted in a jbox behind the chime box, and you run 120 vac to the ...
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13 votes

Is it safe to use a receptacle with wires broken off in the backstab connectors?

Play it safe. Replace the receptacle. What else can you get these days for 71 cents? $1.24 if you get tamper-resistant (which nobody likes but you're supposed to use in many places now) and $2.18 for ...
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13 votes
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Is it safe to use a receptacle with wires broken off in the backstab connectors?

I don’t use back stabs and although code allows them this is by far the largest cause of failed wiring in my experience (worse than aluminum wiring). Since I don’t see a release I would NOT reuse ...
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  • 95.8k
13 votes

Do travel voltage transformers really not have grounding?

TL/DR: there is no way this abomination is certified to any of the usual standards like UL. If a device that requires Earth is plugged into that, it won't be safe. If they ignore such basic safety ...
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  • 5,840
13 votes

Can I replace a 115 V doorbell transformer with a 120 V doorbell transformer?

There are 3 issues here. The one in the title is actually the least of the concerns: 115V to 120V The US electric supply has gradually increased the standard voltage over the past century from 110V ...
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12 votes

How wasteful is a voltage transformer?

The bigger problem is the transformer is going to set you back about $100, so it spectacularly fails to make sense for a $40 humidifier. Dollar for dollar, if you're coming to North America, you ...
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8 votes
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Replacing a doorbell transformer attached to power extension bar

Do not replace the junction box. It is a standard junction box and there is nothing wrong with it. Backstab connections fail more often than transformers Look at the receptacle. See how the ...
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8 votes

exposed doorbell transformer inside a walk in closet

The worst hazard here is snagging your clothes. The transformer is low-voltage, so you can touch the wires and probably not feel anything. If your hand was wet, you might get a buzz, but it's not ...
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  • 26.6k
8 votes
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How wasteful is a voltage transformer?

Something like a dehumidifier which has a fairly high load and a high start up current, will require a larger transformer. Cost and portability will be major considerations. Smaller appliances with ...
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  • 988
8 votes

Cover & sound-suppression for doorbell transformer in utility closet

The best way to eliminate transformer noise is to purchase a quality transformer. The noise is because the laminated core is heavily loaded or overloaded and the plates are actually vibrating because ...
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  • 95.8k
7 votes
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What is this unit attached to my house, and what do I replace it with?

That's telephone. It's not a transformer. It's a terminal block. Call up the phone company and ask them to have someone come out and show you where your point of demarcation is. That's where the ...
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6 votes

AC to DC transformer for LED

The voltage conversion (if nessessary) is done inside the lamp housing that you pictured. This type of retrofit lamp is designed to fit into existing recessed cans that are designed to take a ...
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  • 567
6 votes

Do travel voltage transformers really not have grounding?

I'd say this is a problematic oversight by the manufacturer. The proper cord plug would have a ground connection on it. The European plugs can be a bit tricky as there is actually more than one way to ...
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6 votes

Is there a good way to get 12v into an electrical box?

All you need is a plug-in power supply of a slightly different form-factor, one you're not used to. You're used to wall warts where they have an integral low-voltage cord. That cordage is not legal ...
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5 votes

In wiring a doorbell, what is an alternative to using a transformer?

In the UK, the vast majority of doorbells are battery-powered. On my old-school mechanical doorbell, two alkaline D-cells are lasting me around 3 years. As for why there's an external transformer, ...
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  • 1,770
5 votes

Replacing old doorbell transformer - wiring

The old transformer has identical wire colors for hot and neutral. The new one differentiates them. To connect the new transformer, connect the black wire from the new one to the same black wire where ...
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  • 4,772
5 votes

Can I disable an old security system by disconnecting the transformer?

The wire from the transformer goes into the wall and right back into your alarm panel with the rest of the wires to energize it. Unscrew the wires from the transformer and just tuck them into the wall ...
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  • 53.6k
5 votes

Cover & sound-suppression for doorbell transformer in utility closet

First, even though the exposed wires are low-voltage, likely 16 VAC, they should be covered for esthetics (if the transformer were accessible to children, not inside a closet, it is likely required). ...
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5 votes

What are these transformers in my garage for and how do I disconnect them?

One of them (top picture) is your door bell, and the second one could be the garage opener, sprinkler controller, or low voltage lighting of some sort. Typically, there is an electrical box behind it ...
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  • 312
4 votes

What is this thing on my garage wall?

This is a common way to install a 24V low-voltage transformer. These are used for HVAC thermostats, doorbells, garage door opener controls, and other "control" applications. (For instance, if you're ...
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4 votes

In wiring a doorbell, what is an alternative to using a transformer?

This is where the low voltage and high voltage sections of the UL code interact in an odd and problematic (for you) way. The wire from the chime to the button is low voltage. You also want the chime ...
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  • 3,223
4 votes

Can I buy a 24v transformer with a dedicated common c-wire feed?

Um, I don't know where you got the term "power stealing". What you describe as that, is exactly the normal way to do that thing, and the right way... unless you are aware of some capacity issue on ...
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4 votes

Lifetime of an autotransformer

The lifetime of an autotransformer is indefinite, and does not necessarily end with a short circuit. Barring a transient on the mains, water leak or some other external event, there is no reason it ...
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4 votes

Is this my doorbell transformer?

Anything is possible, but my bet is on a thermostat transformer. Typical (US) thermostats run on 24V AC. Typical doorbells (though there seems to be less consistency than with thermostats) use 16V AC. ...
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