LED Lighting Wiring

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  #1  
Old 08-24-14, 05:55 PM
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LED Lighting Wiring

So I'm having a bit of a hard time deciding how to wire my LED under-cabinet lighting that I need to install before our new tile back splash goes in. The kitchen is finished otherwise.

So my wife would like the LED lights to be dimmable (and I agree with her). So that means wiring in a dimmer. I'd like it to look like a normal wall switch and I'd like to hide the 12V transformer up on top of the the cabinets. In order to accomplish this I think I've got a couple of options.

1) Wire in a 120V AC dimmer off of an existing kitchen outlet and fish the 120 up to the top of the cabinet. I could then either install an outlet or direct wire the transformer. I'm not sure that installing a dimmable outlet is allowable by code thought, and I am also not sure on how to go about direct wiring the transformer since it would need to remain outside of the wall but the splice would need to be in a junction box.

or I could

2) Run the 120AC directly from the lower outlet to a new outlet up above the cabinets. I would then install a plug in transformer and run 12V DC back down in the wall to a new 12V dimmer and then out to the LEDs. I can't seem to find a cheapish UL-rated 12V PWM dimmer though.

Could anyone make a recommendation, or perhaps there is an approach I am missing altogheter?

Thanks!

PS - I wasn't sure if this post should have gone here or in lighting, so I started here.
 
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Old 08-24-14, 06:35 PM
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As a coincidence I was just looking in on a question I had about replacing t-12 fluorescent tubes with led tubes. Something that I have found out is a bit more complicated than your project but not all that difficult.

As to what you want to do you really don't need a transformer anymore. You did need a transformer at one time but now they have made under cabinet lights easier to install. Here is a link to the under cabinet light I found from Lowe's as an example Shop Utilitech 12-in Hardwired Cabinet LED Light Bar at Lowes.com . This light can be installed in series with a wire that plugs in from the side of each fixture.

As for dimming I imagine you need a special dimmer made for led fixtures but other than that not much else that would be designed only for led fixtures. I first became aware of these while watching Hometime and was kind of impressed with how easy they were to install. I am not sure which brand was used it could have been this brand or some other brand. They all though seem to be fairly easy to install.
 
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Old 08-24-14, 06:55 PM
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The downside with those is that they are super pricy for my application. I'm trying to keep this cheap and those would run me several hundred dollars at best.
 
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Old 08-24-14, 07:09 PM
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The one I found was only $34.98 but if you needed quite a few of these which I am sure you probably will I can see how it would get pricey. I haven't priced these except for the brief time I looked at Lowe's website. I myself like these better as you don't have a transformer always running and would probably buy what I needed to start the project and then add on as budget permits. I can see how the other kind would be desirable though but might be concerned about humming sounds and might want to place the transformer in another area if possible.
 
  #5  
Old 08-24-14, 07:36 PM
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You can't tap off an existing kitchen receptacle; you'll have to run a new line or use the kitchen lighting circuit.

I'd go with option 1 but skip installing a receptacle up top. Just run the wire to a box and put a cover over it. Use a cover that has a knock out. Then run a short flexible whip from the box cover to the enclosed LED driver. Maybe something like this for the power supply: Magnitude Dimmable LED Power Supply | Enclosed Power Supplies | LED Power Supplies | Installation/Power Supplies/Misc | Super Bright LEDs | Super Bright LEDs

I assume you'll be using LED tape?
 
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Old 08-25-14, 03:36 AM
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Originally Posted by caddymac View Post
You can't tap off an existing kitchen receptacle; you'll have to run a new line or use the kitchen lighting circuit.

I'd go with option 1 but skip installing a receptacle up top. Just run the wire to a box and put a cover over it. Use a cover that has a knock out. Then run a short flexible whip from the box cover to the enclosed LED driver. Maybe something like this for the power supply: Magnitude Dimmable LED Power Supply | Enclosed Power Supplies | LED Power Supplies | Installation/Power Supplies/Misc | Super Bright LEDs | Super Bright LEDs

I assume you'll be using LED tape?
Yeah I'd be using led tape. Why can't I go off an existing receptacle?
 
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Old 08-25-14, 07:30 AM
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Why can't I go off an existing receptacle?
By code, the countertop receptacles must be dedicated. You can tap off a non-countertop receptacle if you wish.
 
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Old 08-25-14, 10:24 AM
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Shoot. That is what I was afraid of. Would the one from the microwave be allowed since it's a cabinet above the microwave?
 
  #9  
Old 08-25-14, 05:53 PM
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Probably not as most microwaves require a dedicated circuit.
 
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Old 08-25-14, 06:34 PM
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microwaves require a dedicated circuit
If it is permanently fastened in place and has a vent hood incorporated with it then usually on a dedicated circuit (50% rule). However if it is a standalone unit it normally would be plugged into a counter top receptacle.
 
  #11  
Old 08-25-14, 07:57 PM
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It's a dedicated outlet buried in the cabinet with a vent hood and all that jazz.

So I did go down to the breaker box and it looks like my microwave and fridge are a 2-pole 20A breaker together. The problem is it looks like my microwave can draw up to 1800W so that is 15A of the 20A which is over the 50% limit. I've got another outlet inside a lower cabinet that we had installed for running a stand mixer on (using a rev-a-shelf lift so we wanted to be able to plug it in the cabinet). I have to figure out what that is wired to, but I am going to guess its to the other outlets on the cabinet back.
 
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Old 08-25-14, 08:12 PM
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So I did just confirm that the outlet inside the lower cabinet is indeed wired with the ones on the back splash. Only thing I can think of now is that there is a wall outlet in the hallway on the back of of the kitchen. Would it be legal for me to tap off of that? I'm trying to avoid having to run a whole new line because my breaker panel is at the other end of the house.
 
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Old 08-25-14, 08:16 PM
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there is a wall outlet in the hallway on the back of of the kitchen. Would it be legal for me to tap off of that?
Yes, that would be a code compliant solution.
 
  #14  
Old 08-26-14, 04:55 AM
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Just realized the problem with that outlet is that it is right behind the stove and we have a large vent hood so there would be no way to hid the electrical outlet. Could I run down through the basement and back up through a different location?
 
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Old 08-26-14, 06:20 AM
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Yes, any method that allows you to run the electrical cable protected is fine.
 
  #16  
Old 08-26-14, 12:58 PM
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Thanks!

I'm also looking to do this in butlers pantry that is off the dining room. No water or anything there. Just two upper and two lower cabinets. Could I tap off of one of the outlets on the counter there since it's not technically a kitchen?
 
  #17  
Old 08-26-14, 02:29 PM
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I'm also looking to do this in butlers pantry that is off the dining room. No water or anything there. Just two upper and two lower cabinets. Could I tap off of one of the outlets on the counter there since it's not technically a kitchen?
yes.......

Mod Note: I disagree, the dining receptacles are part of the required small appliance branch circuits.
 

Last edited by pcboss; 08-26-14 at 03:55 PM. Reason: added note
  #18  
Old 08-27-14, 05:28 AM
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Oh oh. Conflicting opinions :-) That ain't good. With the Mod Note does that mean any outlet above any counter like surface needs to be dedicated? I guess I can figure out if the outlets in the butler pantry are already hooked to something else (there is only 2 of them) and that would give me an indication of what the building department in my town thinks (it's a new build house and yes I was an idiot and should have just had them wire switches).
 
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Old 08-27-14, 06:17 AM
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BE CAREFUL...............i agree with pcboss and ray2047

you need to run a new 20 amp circuit to safely operate 20 watts of LED lights
 
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Old 08-27-14, 01:09 PM
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So here is a picture of where the butler's pantry is. I circled it in green. On here it doesn't show the cabinets but they are there. Does this help clarify at all?

Name:  BP.jpg
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  #21  
Old 08-27-14, 01:46 PM
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If you turn off the breakers for the kitchen circuits you can check to see if the butler pantry receptacles also go off.

I would look for a lighting circuit nearby to tap into.
 
  #22  
Old 08-27-14, 01:51 PM
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Yeah I was thinking lighting circuit too, but the down side there is that I have more drywall to tear up.
 
  #23  
Old 08-27-14, 06:18 PM
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You guys were right. There is a GFCI circuit in the butlers pantry so no tapping off of that right?
 
  #24  
Old 08-27-14, 07:18 PM
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ALL OF YOU ALL

are making a BIG DEAL out of 20 or 30 watts of LED undercabinet lights

BUG OFF

TAP OFF ANY OUTLET .....to a switch.........to feed an outlet over the cabinets.......plug in your 12 volt transformerr for the 12 volt wiring.

many people plug in their under cabinet lights

Mod Note: Non code compliant answers will not be given on this forum. While this may not be a big deal in your opinion it is in conflict with the NEC. If you would like to change it feel free to submit a change to the NFPA commitees for the 2017.

Plug in lighting is not prohibited but hardwired lighting is.
 

Last edited by pcboss; 08-27-14 at 11:34 PM. Reason: added note
  #25  
Old 08-27-14, 07:43 PM
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It does seem like a bit of overkill to run a whole new wire cable for such a small load. Heck, if I plugged in an incandescent reading light it would draw more power.
 
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Old 08-27-14, 09:30 PM
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I would avoid the butler pantry receptacles, as they as well as the dining circuit is allowed to be on the sabc's. (Although I disagree with that) On most minimum code houses I've been in that's how it's done with 1 circuit on 1 side of the room and another circuit on the other side of the room. Where I would personally tap power off of is whatever circuit the rest of your kitchen lights are powered off of.

I'll admit...the light above my sink is tapped off the counter receptacles.
 
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Old 08-28-14, 12:17 AM
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To the OP,

Some non code compliant information was given above. Please review for technical correctness. While the addition of the small load may not seem to be an issue to some it is a code violation to have hardwired lighting on the small appliance branch circuits, regardless of wattage.
 
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Old 08-28-14, 04:39 AM
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pcboss. Copy that. A lot of times codes are written in a particular way for a reason that we may not fully know. And codes often times are behind the times with what is available in technology. For instance, the lack of codes on low voltage DC wiring. I may just end up running a new breaker that feeds the butler pantry and the kitchen. It'll be a pain, but shouldn't be the end of the world. Of course I say that now. Check back and see if there are any posts from in a few weeks when I start the wiring :-)

The first thing will be figuring out how to drill a hole behind the in the walls floor plate behind the cabinets. I'm making a mental note of how I screwed this up for the next house we build :-)
 
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Old 08-28-14, 07:14 AM
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Matt you have a good understanding and a good attitude. Kudos to you for ignoring the static. Please come back with any more questions.
 
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Old 09-01-14, 10:55 AM
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So any recommendations on how to drill the hole behind the cabinets and into the basement? I've got a 54" but but every time I've tried to use it it just spins. I could drill up from the basement but am afraid of punching through the hardwood floors.
 
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Old 09-01-14, 11:27 AM
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I could drill up from the basement but am afraid of punching through the hardwood floors.
You drill a small indicator hole from above through the floor in a hidden or inconspicuous place as close to the wall as possible. then from below you use that hole as a guide where to drill up.

Plan "B": Run conduit from the basement into the base cabinet. Cut a hole in the back of the base cabinet and in the back of cabinet above for an old work box (staying in the same stud bay). Drop your cable between the two boxes. Install the old work boxes. In the base cabinet install an extension ring extending beyond the wall and run your conduit into that.
 
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Old 09-01-14, 11:53 AM
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bainbridgematt,

Invest in some fiberglass rods for pulling cable. You'll be glad you did.
I've ran cable through some very difficult walls, and sometimes you get lucky and can make a straight shot to where you want to go with only a few holes.
Just a tip: remember you can push cable up from basement or pull it up from above.
Whatever works better. It's good practice for you.
 
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Old 09-11-14, 07:14 AM
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So my next question is does the circuit need to be GFCI or AFCI or neither? Based on what I am reading it probably doesn't need to be either since everything will be direct wired (no outlets to plug into), but I wasn't 100% sure on that.
 
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Old 09-11-14, 06:43 PM
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does the circuit need to be GFCI or AFCI or neither? Based on what I am reading it probably doesn't need to be either since everything will be direct wired (no outlets to plug into), but I wasn't 100% sure on that.
That would depend on what version of the NEC your town has adopted and whether any amendments affect the adopted code.

I'll admit...the light above my sink is tapped off the counter receptacles.
30 to 35 years ago it was common to wire the light above the sink, the disposer and sometimes the range hood from the counter receptacles. At that time there was no requirement for two SABCs, one was usually standard.
 
  #35  
Old 09-12-14, 04:56 PM
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So what would be the most restrictive? If I go with AFCI would I be good reason. Gardless of the year the city is using?
 
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Old 09-12-14, 06:25 PM
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If I go with AFCI would I be good reason. Gardless of the year the city is using?
I think that would be a safe assumption. I believe the 2011 NEC probably would require AFCI protection, but I see no reason for GFCI protection.
 
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Old 09-13-14, 12:22 PM
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Is there any reason that the dimmer must be UL listed? LED PWM dimmers are very basic and even the cheapest ones use standardized design and ICs. For all of my LED strip instalations I've always just done standard (12v DC) power packs plugged into switched outlets (with an inline dimmer, if necessary) as it's much easier then 120VAC dimming and direct wire transformers. At one time, however I was considering doing an in wall 12VDC switch/dimmer using this switch(http://www.diodeled.com/pdf/diode-le...tion-sheet.pdf). It isn't UL listed, but it is ETL listed and the specs say it conforms to UL spec (plus it seems to be very high quality/reliable as the reviews were good.) It's $50 but as it is on the DC side, you should be able to save some money on the DC transformer by not having to buy one that is AC dimmable.
 
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Old 09-13-14, 06:59 PM
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It isn't UL listed, but it is ETL listed and the specs say it conforms to UL spec
That would be a good question for your local AHJ/Inspector.
 
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Old 11-21-14, 11:35 AM
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So I've talked to my inspector and he's on board with everything. The one questions I have for you guys though is related to wiring up the transformer. The company I am buying the transformer from recommends an armored cable that comes out of the faceplate and runs to the transformer. I'm good with that as it seems like a good idea. The one catch though is, where to find a faceplate that has a hole in it for armored cable. In addition, I need to run the low voltage wire back into the box to run it down inside the wall. Any thoughts on how to do that best? I'm trying to keep this install nice and clean with minimal wires running around lose on cabinets.
 
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Old 11-21-14, 11:45 AM
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Just drill a hole in a blank metal plate.
 
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