Questions tagged [transformer]

For questions about transformers, devices which convert alternating current from one voltage to another.

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How can I test and find the polarity of an ignition / step-up coils (that's not connected to a car) using a multi-meter [closed]

How can I test and find the polarity of an ignition coil (that's not connected to a car) using a multi-meter. Just to let you know yes coils can have polarity when DC Voltage is placed on them. https:...
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3 votes
1 answer
984 views

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

update I replaced the transformer and 1 single doorbell with the ring video doorbell wired. Everything is functioning as it should. The existing chime from the standard doorbell is slightly louder ...
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Rhythmic tapping/banging sound on the external AC unit coupled with transformers in the furnace blowing out

We have a strange issue. We bought a house recently. We have several issues: External AC unit keeps making banging sound when heat is on The HVAC furnace stop functioning. In the last 6 months we ...
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1 vote
1 answer
156 views

How can I convert Single Phase 220v to 2 Phase 120v?

I purchased a SMA Sunny Boy 5.0-US-41 Inverter and brought it to the Philippines. Many connections in Manila are 2 Phase 120v. I am in the province, where we have Single Phase 220v. I called SMA ...
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0 votes
1 answer
38 views

Two transformers connected to boiler, no A/C

My HBSmith boiler honeywell circuit box has a 2-wire from transformer to the thermostat. Then there is another transformer on the ceiling that has conduit to the same circuit box, but different ...
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1 vote
2 answers
82 views

Thermostat wiring does not provide +24V AC

A tenant indicated a heat pump failure and that the thermostat display seemed to have been turned off / disconnected. Thermostat was removed, exposing the thermostat wires. The Red and Blue did not ...
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3 votes
1 answer
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Can a doorbell transformer be mounted to a metal junction box which is also being used as a light?

I was recently in my Crawlspace installing a doorbell transformer when I got the idea of potentially reusing an existing junction box. The only problem is the junction box currently has a lamp holder ...
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Adding New External 24v Transformer to Nest with separate Rh and Rc wires

I have separate heat and cooling systems with wiring to Y, W, G, Rh and Rc (see below). For the external transformer, where do I attach the two wires. C and ?
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Doorbell Transformer / Mechanical Chime Questions

I’ve got a 16VAC-30VA doorbell transformer installed near my furnace in the basement. Above the transformer is a Leviton light switch with the words “FURNACE SI (or S1)” which appears to get the load ...
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2 votes
1 answer
296 views

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

I have a bit of an odd situation. I have a standard outlet (120v, 15 amps, just a normal United States receptacle). I'd like to run some raceway conduit up from the outlet*. At the other end of the ...
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2 answers
86 views

How To Select Correct Cable and Transformer For LED Lights

I'm about to install some 12v LED lights and have been surprised by the amount of current required, especially if multiple strips are used, and the effect of voltage drop. I will be installing RGBW 4-...
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1 answer
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Closet light off of doorbell junction box

Good morning, Needed a closet light and had a doorbell transformer in the closet so I run a light off of that junction, finding out covering the transformer is not up to code. Problem is exposed 115 ...
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2 answers
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Use halogen transformer for Ring video doorbell wired

I am planning to install a Ring branded video doorbell at a home I am visiting for a few days. We are struggling to find a doorbell transformer on short notice, but did find a halogen light ...
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4 votes
1 answer
1k views

How to get 24V from this transformer

I'm confused - the arrows in this picture of a doorbell transformer range from 8V - 24V with arrows pointing just about everywhere. I think I need to buy this to get enough power to a Nest doorbell. ...
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2 votes
0 answers
140 views

mounting thermostat transformer in wall on old work box

I want to know if the following is reasonable and to code: I want to install a wi-fi thermostat that requires 24v AC but the existing thermostat has no C-wire. So I want to install a 24V transformer ...
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29 views

Connecting 2x halogen lights to a ECT T90 230/12V 50VA transformer which is operated by a step switch

I got this wall unit which has two halogen lights. The transformer is mounted on top of the wall unit and all the wires are there but no connections are made. The 2 lights are controlled by one step ...
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2 votes
1 answer
74 views

Outdoor low-voltage transformer off of sconce? Possible?

I have a raised deck with walkway underneath. I'm in the process of resurfacing it and I'd like the switch to the sconces above and below the deck (different switches) to also light the deck (above ...
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Safety question about isolating transformer

I have a situation identical to the one linked below and I was wondering what others might think. Electrical professionals have told me two different things and I want go with the safest option. I ...
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0 votes
1 answer
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Do I have the right supply list to start my under cabinet LED project?

Thanks for all the recent help on here. I am gathering supplies for an under cabinet RBGW LED project (US). So far I have: RBGW 12v LED Strip Lights 100-240v to 12v Transformer Wireless Controller ...
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If my HVAC Fan Is drawing to much amperage will it burn the relay and the transformer

First I found My 24v transformer was dead, I replaced it and it burned out in 15 seconds apx. Then I checked all T stat and control wires they checked ok no shorts. The AC unit runs fin if I manually ...
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0 votes
1 answer
117 views

120v from 240v with a transformer

I have 240v over Hot-Hot-Ground which is feeding to a sub-panel for a pool. Sub-panel will have a 30amp 2-pole breaker for the pool pump and a 15amp breaker for the lights. I need 120v for the pool ...
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2 votes
1 answer
2k views

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

I just bought a house and there are two transformers in the garage. I'm trying to figure out what they do. The house was built in 2014 and located in San Mateo, California. I suspect one of them is ...
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1 vote
1 answer
151 views

Hide an adapter in ceiling

I am installing in-ceiling speakers. However those come in with an adapter that transforms from 100-240V to 24V. I want to hide the adapter, preferably in the ceiling of my house. According to NEC ...
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1 vote
1 answer
240 views

R and C wiring for Air Handler and Zone Panel

First time posting a question! But have been reading the questions/answers here for a while now. Ok- so I have a brand new Goodman Heat Pump system (GSZC + AVPTC air handler) I’ve installed in my ...
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2 votes
1 answer
2k views

Blowing up a doorbell transformer

My house is a 117 year old masterpiece of evolving building codes and improvisation. One of the things I expect to do at some point in the future is get a doorbell camera, though it's not on the ...
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1 vote
1 answer
80 views

How to properly use a transformer which bundles its high & low voltage wires together?

Here's an example of an HVAC transformer that will go from 120 or 240 to 24 VAC. Obviously, all wires exit the device through the same pipe nipple; the device is intended to be installed by screwing ...
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1 vote
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226 views

What is the correct safe way to wire ground in a domestic 110/220 step transformer?

I am not an electrical engineer and do not have a deep understanding of all the different factors in transformer design. My question is about a plug-in 2:1 step up/down transformer used for 120/240 ...
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10 votes
8 answers
3k views

Do travel voltage transformers really not have grounding?

Example 220v-to-110v converter here. It seems like it accepts a 110V plug with grounding, and yet the converter itself only has a two-pronged plug (to a 240v outlet). Does this mean that plugging a ...
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0 answers
315 views

Doorbell has no voltage, but chime wires always have voltage

I just moved to a new place and trying to fix the doorbell. There are 2 doors, frond and back, neither one is working. I found a doorbell wire image on Google: However, it's very strange to see the ...
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1 vote
2 answers
71 views

24vac transformer inside furnace

I'm adding a humidifier to my furnace. The included 24vac transformer fits nicely on the inner electrical box in the upper furnace compartment. I like that it keeps everything behind the external ...
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3 votes
3 answers
280 views

Replacing Doorbell Transformer

I currently bought a Ring Doorbell and am trying to locate my transformer that powers it since it is unable to activate my indoor chimes. I'm in a condo and do not have access to the attic but do to ...
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1 vote
1 answer
61 views

Transformer going into receptacle obstructed by board behind it

I am in the process of upgrading my doorbell transformer. (I am the fella from yesterday with the question about broken off back stabbed wires, registered with a proper account this time) In addition ...
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5 votes
2 answers
1k views

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

I bought a new doorbell which required me replacing my transformer. My current transformer is attached to a receptacle that sits right below my panel. Turned the power off to it, unscrewed it, found ...
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1 vote
3 answers
376 views

Is it ok to pigtail different gauge transformer wires with a 15 amp circuit?

I have a 15 amp breaker that’s used for my foyer/family room. The builders double tapped that breaker to add a 16V-10VA transformer for the doorbell to the side of the service panel via a knockout. ...
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0 votes
2 answers
297 views

DC Landscape Lighting Transformer

I'm planning an installation of twelve 12VDC deck post cap lights, each drawing 1.6 watts. The manufacturer says the lights must be driven by a DC supply. They offer a system that uses a 50 watt ...
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1 vote
3 answers
356 views

Sizing a landscape lighting transformer

I'm surprised this hasn't come up before but I did a search here and didn't find anything, so here goes. I need to power a dozen 12VDC LED deck post lights, each drawing 1.6 watts. I want to place ...
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0 votes
2 answers
148 views

240v plug, converter or transformer for EU kitchen appliance in the US

My Kenwood Major Cooking Chef (KM096) being my prized kitchen appliance, is the only one EU machine I've taken with me to the US. It would have been much more expensive to replace and letting it sit ...
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2 votes
2 answers
729 views

How should I replace door chime transformer at breaker panel?

I'm replacing a door chime transformer with a new 16v 30va transformer to accommodate a new Ring doorbell. The existing transformer is attached in our circuit breaker panel through a knock out at the ...
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0 votes
1 answer
64 views

AC to DC transformer for LED

Can someone tell me where AC to DC conversion happens in this type of LED light ? This is retrofit LED light which fits into can which has AC current. How and where does it step down voltage and also ...
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7 votes
2 answers
666 views

Why bother referencing neutral to ground in residential transformer?

I'm going to list the 3 scenarios for electrocution I can think up for both a residential transformer with grounded neutral and an isolated transformer. I find that the grounded neutral transformer ...
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1 vote
1 answer
3k views

Where to put my doorbell transformer for new wired doorbell in old house?

I used to have an old whole house intercom system with an integrated transformer inside the kitchen wall, far from the front doorbell. For the new basic doorbell, I was planning to power the doorbell ...
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0 votes
3 answers
422 views

Placement of transformer for indoor/outdoor LED light string

The LED light string is labeled for Indoor/Outdoor use but there is a warning on the box that the transformer must be indoors. That seems as though the light string is NOT suitable for outdoor use. I ...
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0 votes
1 answer
799 views

Can I directly add a Common wire to this point on a 24VAC transformer, or will load be too high? (70mA)

Referencing This excellent answer I have a two wire furnace controller, 24VAC, no common. I measured the current draw of the relay (when the thermostat wires are shorted), it draws 0.2A Wish to add an ...
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2 votes
2 answers
6k views

Doorbell transformer wiring to an electrical outlet?

I just bought a new doorbell transformer (24V 40VA), to replace for current one (10V 5VA) because I bought a video doorbell. I'm don't have any experience with electricity but I'm willing to learn (...
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0 votes
1 answer
61 views

Low voltage LEDs fluctuate from full to half to off and repeat

I purchased and installed 100' of 16/2 wire and eight lamps (LED Lawn Light 12W 2800K AC/ DC 12V) and Malibu’s 200 Watt Low Voltage Transformer. 96 watts of lamps, I was told, would be perfect for a ...
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2 votes
2 answers
1k views

Cover & sound-suppression for doorbell transformer in utility closet

This transformer is installed in the utility closet of a 1970's condo. Notice the wad of cut paper sheets pinched between transformer and the wall plate. This is an attempt at halting a low-tone ...
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2 votes
2 answers
3k views

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

I switched from my old security alarm to a diy alarm system. I want to completely shut down the old alarm system and keypad. Is I possible to remove the wires of the transformer? I don't know what to ...
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1 vote
1 answer
355 views

Blown Thermostat Twice and Dead Transformer

A year ago, I had a brand new smart thermostat that caused the A/C fuse to keep blowing. I replaced the thermostat with a duplicate, swapped the fuse out and everything has been fine. Now a year ...
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3 votes
2 answers
234 views

Transformer won't work for US plug

I live in the UK but have a few US appliances in my possession which I would like to use here in the UK. To avoid having to rewire all the plugs, I bought a transformer to step down the voltage from ...
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0 votes
2 answers
78 views

mounting a power-splitter on a foreign electricity transformer

I'm using a 110V→220V foreign electricity transformer (image attached). Is it possible / safe to mount a power-splitter on the transformer, to allow multiple 110V devices to be connected ...
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