Appropriate gauge for LED Recessed lights?

[sfanale]

Hi All,

I have started thinking through my lighting setup and I have some left-overs from another project that I wanted to utilize in the garage to save $$$. I am aware that I need to calculate the total load from the lighting fixtures to determine the correct breaker/wire combo, which seems easy enough. I want to place 15 recessed lights throughout the garage, each LED is 15W so that's:

15W*15 fixtures = 225 total watts for lighting.

Obviously, that is a pretty low figure because they are all LED cans, so I know safety-wise I am plenty safe with 14/2 romex and a 15A breaker. These are the exact fixtures I was going to use:

http://www.homedepot.com/p/Commercial-Electric-6-in-Aluminum-Recessed-IC-New-Construction-Airtight-Housing-6-Pack-CAT7ICATA-6PK/202256649

My question is... because those are "standard" style housing which have a bulb socket (I would use LED retrofits that screw into the socket), can I still use 14/2 romex and a 15A breaker? OOOORRR, because theoretically someone could throw standard bulbs in, which would have a MUCH higher power draw, do I need to wire to the potential total power? Something more like:

100W * 15 fixtures = 1,500 total watts

If it's the latter, I obviously need to go with 12/2 romex and a 20A breaker. I realize there is not a big difference in price, but I am never going to use normal bulbs, so I figure why over-wire it if I don't need to? I fear I already know the answer, but what would the NEC say; Wire to the actual usage or to the theoretical max? Your expert advice is greatly appreciated.

 

[CJ7VFR]

It is hard to say which way to go. If the light cans says somewhere on it that a 100 watt bulb is the max you can use, then even if you never mean to use those in the cans, you might want to upgrade the wire and go with 12 gauge just for the peace of mind.

I would personally do it just for the fact that because it is in a garage then I would probably end up adding a few more lights to the string someday, and to know I could do that would be great.

If you HAVE to upgrade the wire to 12 gauge because there is a potential that someone, someday, might, maybe, put 100 Watt incandescent bulbs in there, then one of the sparky's here will tell you for sure once they see your post.

Give it a day and I am sure you will have a ton of replies to your question!

Jim

 

[AntonLargiader]

In the Q&A for that item, customer service says the fixtures have no watt rating because that is determined by the trim.

The breaker is there to protect the wiring from overload. I think it's ridiculous to run 12g wire on a 15A circuit for 2A of lighting.

There's nothing stopping you from trying to overload a receptacle circuit the same way...

 

[jdsac]

I had the same situation, screw in sockets with screw in retrofit led adapters.
The housings were rated at 75 watts max in the unlikely event someone were to put in 75 watt bulbs I sized the wire accordingly. When I added up the lights x 75 watts 14 ga was fine. That covered worst case.

By the way, I used that exact can & the sticker inside says it's rated 75 watts-
have a look at the store and verify, they might have changed.

Also look at these- they put 2 romex (the in & out) thru the same hole in the make up box on the can which makes the connection to the wago in the can easy as both the wires are in the same plane

http://www.homedepot.com/p/Halex-3-...sh-in-Cable-Connectors-5-Pack-27580/100148292

 

[cybrdyke]

because theoretically someone could throw standard bulbs in, which would have a MUCH higher power draw,

If this was a commercial space or even a new construction residential fixture, it would get counted by an inspector using the Max wattage allowable as stated by the manufacturer, in this case 75 watts. You would need to size the wire and breaker accordingly.
Good luck,
CD

 

[sfanale]

If this was a commercial space or even a new construction residential fixture, it would get counted by an inspector using the Max wattage allowable as stated by the manufacturer, in this case 75 watts. You would need to size the wire and breaker accordingly.
Good luck,
CD

Thanks everyone! I went to HD and I read the sticker inside which is actually a small table listing several types of bulbs; the max listed was 75watts. So following your advice, I'll stick to that, therefore:

15A * 120v = 1,800 watts
1,800 watts * 0.8 (for some overhead) = 1,440 watts total
1,440 watts / 75 watts per fixture = 19.2 fixtures "safely"

Always show your work! In reality, I'm only planning to hang 16 LEDs so I'm so far below the max. Thanks everyone for the responses. Time to get to wiring...

 

[donpauli2]

I use #12 for most everything 20 amps or less just cause I don't have to worry about it.


Sent from my iPhone using Tapatalk

 

[ard]

How much will you save using #14?

I mean you buy wire by the 250' or 1000' roll, right? not 'by the foot'.

Lets say you need 150 ft of #12 and 100 ft #14. The cost differential on the per foot is way smaller than the wasted lenghts you wont use- even buying a 100ft roll of #14. IMO the savings on the wire you use is countered by the wire you buy but dont use....

Of course, in this example it is TOTALLY dependent on how much wire you need. I agree with the poster above- just run #12 and be done with it.

 

[AntonLargiader]

We as a society are probably not going back to arrays of can lights that draw 75~100W each. That is really stuff from the past at this point. I get the idea of using the fixtures you have on hand, though, but it's interesting that the overrating can hurt you.

If code lets you pull 14, I would because it's easier to work with.

 

[sfanale]

How much will you save using #14?

I mean you buy wire by the 250' or 1000' roll, right? not 'by the foot'.

Lets say you need 150 ft of #12 and 100 ft #14. The cost differential on the per foot is way smaller than the wasted lenghts you wont use- even buying a 100ft roll of #14. IMO the savings on the wire you use is countered by the wire you buy but dont use....

Of course, in this example it is TOTALLY dependent on how much wire you need. I agree with the poster above- just run #12 and be done with it.

I can appreciate the ease of just over wiring with #12...set it and forget it. I happen to already have all the 14/2 from another remodel, so the cost savings would be 100% of the cost of the 12/2 I don't buy. I also was just curious of the offical NEC rule for wiring lighting like this, so that I know down the line on the next project.

 

[sfanale]

We as a society are probably not going back to arrays of can lights that draw 75~100W each. That is really stuff from the past at this point. I get the idea of using the fixtures you have on hand, though, but it's interesting that the overrating can hurt you.

If code lets you pull 14, I would because it's easier to work with.

Agreed on both points. I am going with #14 and just limiting the cans to 19 max so I meet both the code and the ease of use with lighter wire.

 

[prostreetamx]

In my local jurisdiction we can only put 12 light boxes or fixtures on a circuit whether 12 or 14. Sometimes this was an issue for situations like yours where you have more fixture you want to control with one circuit. There was also the opposite issue where they would have counted a bar light in a bathroom that could have up to 8 sockets per fixture. We always took the actual fixture into account when designing our circuits for tract houses. We also uses #14 for lighting whenever possible because it was cheaper than #12 and that is a big factor when you are wiring dozens of houses at a time. We used #12 for small apartments because you could mix lighting and plug circuits which saved long runs to feed a porch light or closet fixture since you could just add them to the nearest plug circuit. This was before AFCI's but now they make you AFCI light fixtures in bedrooms anyway so not a big deal.