wire gauge needed for leds

Thread Starter

zwo

Joined May 4, 2010
14
Hello everyone,
I just needed to ask the experts here for a little help please. I want to connect 2 led strips to a 12 volt regulated power supply, 1 strip draws 5 amps and the other 10 amps. I have a 30 amp 12volt supply. What gauge wire should I use foreach strip? Thank you for your help.
 

Tonyr1084

Joined Sep 24, 2015
6,459
Off hand, a total of 15 amps of current would typically be handled by a 14 gauge wire. For individual strings, I'd use no smaller than a 16 gauge for the 10 amps and no smaller than 18 gauge for the 5 amps if you're wanting to run separate wire sets. You can probably get by on the 10 amps with 18 gauge but why chance it?!
 

MisterBill2

Joined Jan 23, 2018
9,844
Aside from the current ratings of wire sizes, which are done for temperature rise considerations, there is a voltage drop concern that matters a bit more for LEDs. So the size choice also depends on how long the wires will be.
 

Reloadron

Joined Jan 15, 2015
6,218
So total current draw is 15 Amps. To allow a little headroom I would suggest AWG 12 which is about 2.32 mm depending on if you want US numbers or Metric numbers. Also the run length, as mentioned, is important. However for a short run (distance) of under 10 feet or 3 meters I would not worry about it. Those numbers are pretty high current for LED strips, you are sure they are correct? As to each strip individually for the 10 Amp I would go with AWG 14 (1.628 mm) and the 5 Amp AWG 16 (1.291 mm) assuming short ruins and each strip individually connected to your supply terminals.

Ron
 
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MisterBill2

Joined Jan 23, 2018
9,844
So total current draw is 15 Amps. To allow a little headroom I would suggest AWG 12 which is about 2.32 mm depending on if you want US numbers or Metric numbers. Also the run length, as mentioned, is important. However for a short run (distance) of under 10 feet or 3 meters I would not worry about it. Those numbers are pretty high current for LED strips, you are sure they are correct? As to each strip individually for the 10 Amp I would go with AWG 14 (1.628 mm) and the 5 Amp AWG 16 (1.291 mm) assuming short ruins and each strip individually connected to your supply terminals.

Ron
The national electrical code specifies #14 for 15 amp loads, and that is very conservative, really. #12 wire is rated to carry 20 amps constantly, and so is much more than is needed. #16 and #18, as first suggested, will work out very well unless you are running the wires a very long distance, like a few hundred feet.
 

Reloadron

Joined Jan 15, 2015
6,218
The national electrical code specifies #14 for 15 amp loads, and that is very conservative, really. #12 wire is rated to carry 20 amps constantly, and so is much more than is needed. #16 and #18, as first suggested, will work out very well unless you are running the wires a very long distance, like a few hundred feet.
Yes, I agree but figure the cost difference is not very much between AWG 12 and AWG 14 so I went with the 12 AWG overall. Also the thread starter gave no clue as to location and I have no idea if he wants AWG wire gauge or wire gauge expressed in millimeters? I intentionally left overhead based on what you mentioned. No clue if he or she has a run of a few feet or meters or a run of a hundred feet or meters. So considering wire cost I went considerably over in my advice. I know what the NEC proposes along with NFPA. A little overkill headroom won't hurt. Also thread starter mentions nothing about environment? Things like UF (Underground Feed) burred cable or anything else?

Ron
 

MisterBill2

Joined Jan 23, 2018
9,844
Around here, at Home depot, the difference between #12 and #14 is significant, in fact it is appalling. In addition #12 wire takes more effort to terminate, at least the solid certainly does.
 

Tonyr1084

Joined Sep 24, 2015
6,459
#12 wire takes more effort to terminate
OH HELL YES it is. Did my shop in 12 & 14 gauge. 12G for 20A outlets, 14G for lighting. 12 just doesn't want to be pushed into those boxes.

For what the TS wants to do, in my opinion, unless we're talking about long runs, 16 and 18 gauge stranded wire. After all, we may be under the impression the power sources are 5 & 10 amps. The lamps themselves may draw significantly less power. Nobody thought to ask that question. The TS states these strings are 5 & 10 amps, but those may be the power supplies that came with them. Clarification is needed.

Is the operating amperage of each of these LED Strings 5 & 10 amps - OR - did they come with their own power supplies that are rated for 5 & 10 amps?
 

Reloadron

Joined Jan 15, 2015
6,218
Well alrighty. I am not going to suggest running any wire at its maximum current. The thread starter was very clear his total load would be 15 Amps and based on that I will suggest AWG 12 for a constant 15 Amp load. I also find no real significant difference in terminating THHN or THWN AWG 14 verse AWG 12. Anyway for a 15 Amp load I simply won't suggest AWG 14. The thread starter asked and I gave my answer. The thread starter also pointed out they had a 12 Volt SC 30 Amp supply with no mention of fusing or any overload protection so can do whatever they want.

Ron
 

MisterBill2

Joined Jan 23, 2018
9,844
If #14 wire is approved for 15 amps by the national electrical code then it is obviously nowhere near "it's limit." At 15 amps #14 wire does not have any significant heating. And for reasonable lengths heating would be the limiting factor.
 

Thread Starter

zwo

Joined May 4, 2010
14
Hello everyone,
I just wanted to say a very big thank you to all that answered. The leds will be for Christmas decorations and I am in Montreal Canada where it get cold and windy during the winter , not to mention the humidity. I have to consider the weight of the wire, and flexability also. I will go shopping around Homedepot soon. I am thankful for this website and all the knowledgeable people that are kind hearted enoigh to help a stranger.Bye for now
 

MisterBill2

Joined Jan 23, 2018
9,844
You will find that the thinner wire costs a whole lot less than the larger diameters. And given the cold weather heat will not be a consideration. #18 will work, #16 will provide more margin.

Of course, with a 30 amp power supply you do need to provide over current protection, either circuit breakers or fuses. That is important, we forgot to mention it.
 
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Thread Starter

zwo

Joined May 4, 2010
14
You will find that the thinner wire costs a whole lot less than the larger diameters. And given the cold weather heat will not be a consideration. #18 will work, #16 will provide more margin.

Of course, with a 30 amp power supply you do need to provide over current protection, either circuit breakers or fuses. That is important, we forgot to mention it.
Hello again, Thank you Misterbill2 Very sorrry about the delay in answering I was at the hospital for tests. The power supply I am using has short circuit protection built in but I plan to install a slow blow 15 amp fuse. I greatly appreciate all your help . The leds strips will be installed in Christmas inflatable decorations . So let me wish you very Happy Holidays . Bye for now zwo
 
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