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 ...
Michael Karas's user avatar
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25 votes
Accepted

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 ...
Harper - Reinstate Monica's user avatar
24 votes
Accepted

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 ...
crip659's user avatar
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21 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 ...
Harper - Reinstate Monica's user avatar
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 ...
Ecnerwal's user avatar
  • 210k
14 votes
Accepted

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.
keshlam's user avatar
  • 28.6k
14 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 ...
bobflux's user avatar
  • 9,168
13 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 ...
shirlock homes's user avatar
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 ...
manassehkatz-Moving 2 Codidact's user avatar
13 votes
Accepted

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 ...
Ed Beal's user avatar
  • 103k
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 ...
manassehkatz-Moving 2 Codidact's user avatar
13 votes

What’s the ampacity for 18 AWG wire, at 24 V AC

What’s the ampacity for 18 awg wire, at 24v AC Safe ampacity does not depend on voltage. However, it does depend on ambient temperature, insulation temperature rating, wire material, and other ...
ickybus's user avatar
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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 ...
Harper - Reinstate Monica's user avatar
10 votes

wiring a 100amp subpanel to my barn 600ft away from my 200amp service panel

The "20% per 100'" rule of thumb you found there isn't very good. It's excessive for short distances and insufficient for long distances, and this is the latter. Anyway, Voltage Drop ...
Harper - Reinstate Monica's user avatar
9 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 ...
Ed Beal's user avatar
  • 103k
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 ...
Harper - Reinstate Monica's user avatar
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 ...
JPhi1618's user avatar
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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 ...
mongo's user avatar
  • 1,008
8 votes
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Why does hooking voltmeter to two transformers show 0 voltage?

To measure voltage, you need a complete circuit. Connect a voltage meter between a hot 120V wire anywhere in your house and a neutral wire anywhere in your house and you will get 120V because the ...
manassehkatz-Moving 2 Codidact's user avatar
8 votes
Accepted

Protecting out-of-wall wiring to transformer

The PSU is well chosen and is either UL listed, or would be if they applied for it. How refreshing to look up a street address on Google Earth and find an industrial park, instead of a Mailboxes Etc....
Harper - Reinstate Monica's user avatar
8 votes

Connecting LED lights to AC Power (flicker @ 50hz)

You're not going to like this solution: Buy Better Quality Lights There are a bunch of different ways to convert 120V 60 Hz or 240V 50 Hz power to low-voltage DC to power LEDs. Some of those methods ...
manassehkatz-Moving 2 Codidact's user avatar
7 votes
Accepted

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 ...
Harper - Reinstate Monica's user avatar
7 votes

Old doorbell transformer wired directly into electrical box, don’t know how to disconnect without cutting the wires?

The most common setup is a junction box with wire nuts. However, in your case the original installer did a mostly good thing by installing it on the panel. The only bad part, in my opinion, is that ...
manassehkatz-Moving 2 Codidact's user avatar
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 ...
bigchief's user avatar
  • 761
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 ...
ScienceGeyser's user avatar
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 ...
Harper - Reinstate Monica's user avatar
6 votes

Protecting out-of-wall wiring to transformer

Your PSU is nicely designed to interface with a metal junction box and to provide HV/LV separation to code. I'll focus first on the 120V side. Because you have plastic wall boxes you cannot install ...
jay613's user avatar
  • 36.9k
6 votes

What’s the ampacity for 18 AWG wire, at 24 V AC

To answer the question you asked: Assuming you are under NEC, 310.15(B)(16) only lists 90°C for 18AWG insulation (presumably because they only expect to see it inside fixtures) at 14A for not more ...
Ecnerwal's user avatar
  • 210k
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, ...
Graham's user avatar
  • 2,028
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 ...
PhilippNagel's user avatar
  • 4,947

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