26

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 electrical junction box similar to the following. Liable to be found in garage or basement fairly close in distance to the bell button and bell unit. Picture ...


19

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 sea of accident reports. They are using field data to "min-max" for minimum casualties. What you're talking about is an isolated system. That is a ...


18

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 transformer.


14

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.


13

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 transformer, but all the actual chime and buttons must be wired from the low voltage side of the transformer. It's a simple series circuit.


12

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 may be better off just adding a couple 240V circuits to your house, and running the appliances off 240V straight shot. North America has both 120V and 240V ...


8

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 wires are connected? They're "back wired" with a backstab style connection. That is only allowed for 14 AWG solid wire, the receptacle's labeling plainly says ...


8

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 dangerous. Some transformers can get warm, but doorbell transformers normally do not because they are very low power devices. You could hang a shoebox on it or ...


8

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 low current draws, will be easier to fit to a small transformer. For reasonable quality transformers, figure a loss of about 3%.


8

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 of eddy currents. I can’t quite make out the size, but it looks like 24V, 20VA. I would bump it up to a 24V, 40VA unit that would be compatible with video ...


7

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 wires stop being their responsibility and start being your responsibility (unless you have an in-house service plan as part of your bill). It looks like an ...


6

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 reflector bulb with a standard base. If you disconnect the orange connector and screw the base adapter into a bulb socket, a voltage meter will show 120v AC at the ...


5

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, that's simple. It's not "antiquated", it's actually a modern phenomenon. All mains-connected equipment needs safety testing (CE, TUV, or whatever your local ...


5

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 by the outlet in case you ever want to use the panel again. Tuck the transformer into the alarm box and shut it. There doesn't appear to be any backup ...


5

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). That said, the buzzing noise is likely being transmitted to the metal plate and wall, which make it much louder. A few things to reduce the buzz: Remove the ...


4

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 hooking up a Nest thermostat and looking for the "C" wire, it's one of those. The other is the "R".) Here, the transformer is part of a junction box cover ...


4

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 itself to be powered directly from high voltage. The two voltages cannot be placed in one junction box. So your desired doorbell chime unit must support ...


4

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 the transformer (as is sometimes seen in transformer-relay combos). As far as the R and C terminals, any HVAC transformer has two pins on the 24V side... They ...


4

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 should fail. However, if the low-voltage part of the winding were to open (as well as if the high side were to short), you'd also be faced with full line voltage ...


4

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. Get a multimeter. Test the voltage: 24V - Thermostat 16V - Doorbell Something else? Post it here and we can try and figure it out.


4

Because you have too much lighting load for the power supply (not transformer*) to cope with, so it is crowbar-ing. Reduce load. This is a good time to think LED. * "Transformer" is a proper term for a very specific thing, which this is not. Transformers are quite heavy and withstand short-term overload very well. This weighs 6.4 oz. for 150W, and ...


4

Adding transformers will not "stabilize" anything, I have no idea where you got that idea, but it's wrong. Sometimes people step up the voltage to a higher level (like 480V) and back down again for a long distance run so that the current is less, because less current results in less voltage drop since voltage drop is a function of I (current) Squared / R (...


4

Straight up You cannot afford to fall below 110V. Ok. Supply at your house is supposed to be 120V so we have a little room to play with. If you use 8 AWG cable, voltage drop will be limited to 8.29V on a full 20A load, giving 111.71V. That meets your criteria. If actual pulled amperage is less, voltage drop will be proportionately less, and ...


4

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 your old transformer was connected with the wire nut. Connect both the green and white wires to the same spot where the black and green are connected together ...


4

You're wasting about 2-3% of the transformer rating in inefficiency. If you're switching secondary voltage, then you're paying for the primary winding losses 24 hours a day even if there's no load on the transformer. The transformer is just one more item that can fail and leave you without your appliances.


4

The transformer is in a box so it’s not horrible but normally a doorbell transformer is mounted outside the box , the 120v connections made inside and the low voltage connections made outside the box. In this case both high and low voltage are in the same compartment , that would not fly in my jurisdiction with out a non conductive shield (plastic insulator ...


4

Is the actual problem "I need to power a bunch of 120V devices" or is it "I have a bunch of gadgets that need correct power" ? There is quite a difference. In the picture, it looks like a power adapter (a.k.a. "wall wart") is plugged in. Many wall warts (or other types of adapters, like "laptop bricks") can actually ...


3

No matter what you do, yes, you have to follow electrical codes (in North America, the NEC), and this means proper enclosures for any mains voltage stuff. The NEC doesn't have anything to say about low voltage (<= 30V) wiring. Essentially this comes down to preference, there's no right answer as to what is 'better'. A hard-wired solution can have a ...


3

Here is how manufacturers make an appliance one voltage or another. electronic switch-mode power supply. These can input a huge range of voltage, for instance many fluorescent ballasts take 90-306V. If you see that, don't be surprised, it really works. The machine runs on low-voltage AC or DC from a pluggable "wall wart" transformer, and they simply ...


3

You're not measuring the amperage, you are measuring the voltage. Set it to measure DC Volts on the 20 scale, read. The maximum voltage for the meter is printed right on it, 600. The device you have is not a transformer, it is a DC power supply. When you connect your lights, measure the voltage again with the lights connected. Don't try to measure the ...


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