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Where would you put the 12V transformers for display cabinet lighting?

Where would you put the 12V transformers for display cabinet lighting?

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  #1  
Old 09-11-13, 02:28 PM
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Where would you put the 12V transformers for display cabinet lighting?

I can't decide which option to choose. I am not as familiar with the flexibility of 12V Class 2 wiring methods, but I am quite experienced with the much stricter 120V wiring.

I have 8 upper glass display cabinets where I want to put 20W lights in each, and some 60W 12V Class 2 transformers to hide somewhere.

1. I can put a metal box with the transformers in the cabinet above the oven. The plus is that it would be readily accessible if a transformer burns out. But all the wire runs would be cumbersome in this configuration, because of the placement of some of the display cabinets on the opposite wall. With the longer wire runs on the secondary there would be more voltage drop unless I use pretty thick wire even for the low voltage wire.

2. I can slip the transformers inside the cabinet ceiling hole used to recess mount the puck lights. There is a 2 inch cavity between the room ceiling and the upper display cabinet ceilings. If the transformers live inside this cavity they would be accessible when the lights are removed, the secondary wire runs would be very short. However the challenge would be that the 120V connection needs a junction box, and there is no room inside this 2 inch cavity for a junction box unless I get creative somehow with a ceiling lamp box (how could I slide it in this gap and get it to fit, without cutting a giant hole in the cabinet ceiling).

3. I can put the transformers inside junction boxes in the attic. There is some design flexibility here, as to how long the secondary wires should be, depending if I group the transformers together or put them in separate boxes. But it gets really hot in the attic and the transformers would be a little harder to access. A bigger concern of mine is that I think the low voltage wires cannot penetrate the ceiling without being inside a conduit (is that correct?).
 
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  #2  
Old 09-11-13, 02:35 PM
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The attic should be a last resort as the heat is an issue.

How about the basement ? Bring the wiring down the walls.
You should use 12-2 or 14-2 romex for your low voltage wiring.

Romex does not require any conduits.
 
  #3  
Old 09-11-13, 06:08 PM
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I don't have a basement, rather a concrete slab. I was thinking about using Romex for the low voltage side. But then I read about people running into problems with electromagnetic interference to their radios and other equipment when they used longer runs of low voltage wiring inside the house. So I am thinking maybe I should use metal FMC for the low voltage side as well to shield from EMI. But that would be clunky to wire up with 9 (8x 12V, 1x 120V) cables entering the cabinet if I put the transformer inside the cabinet above the oven. Class 2 low voltage is supposed to be flexible as far as what's allowed, but for me it's turning out to be way more puzzling to figure out compared to the stricter 120V wiring.
 
  #4  
Old 09-11-13, 08:52 PM
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Have you considered using a double-gang box mounted at the rear of your cabinet, cut into the cabinet/wall? The transformer goes in there, and is readily accessible if needed. You can mount it in an adjacent cabinet so you choose one that doesn't have glass fronts.
 
  #5  
Old 09-12-13, 09:57 AM
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Xenon Puck Lights - 5-Pack at Menards


Line voltage lights will be more efficent are dimmable and dont have the problems with bulky/faulty/hot transformers and low voltage wiring, if your wire is real long you will notice that the end light is dimmer than the first


Ive installed a dozen of these kits on diffrent jobs
 
  #6  
Old 09-12-13, 12:43 PM
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braether3 - I like your idea of line voltage lights. Actually this was the first option I considered.

I changed my thinking to 12V after I noticed that there is a much wider choice of 12V light fixture styles available.

But for the reasons you mentioned I may just go with 120V Xenon lights even though the fixtures are harder to find in the style I want.

Makes me wonder why 12V is more widespread. I am starting to think that low voltage wiring is over-hyped (transformer wiring hassle, big voltage drop without really thick wires), and LED is over-hyped as well (flat color rendition even with today's technology).
 
  #7  
Old 09-12-13, 01:03 PM
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the main reasons are safety, though its a loose definition of safety, in that the wiring can more safely be done by the homeowner with out him frying himself. Imo a person is better off to properlly install 120v lights and skip the transformers unless going LED.
 
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