I have a bunch of leftover sprinkler cable, 18/5 solid copper. The product description from the manufacturer says it can also be used for low voltage landscape lighting.

I need to run an extension from a power supply to LED light strips, 24V. Most of the cables sold as RGBW extension are actually 22AWG stranded, but I do see some 18AWG stranded as well.

Is there any reason I couldn’t use the sprinkler cable? Is there more to it than just the wire gauge?

Based on my understanding, stranded would allow some movement without breaking, but I’m not sure if that would be a concern.

I’ll be using this under a covered porch.

  • What ratings does the cable have? Is it UL listed for indoor/low voltage use? Apr 3, 2020 at 4:16
  • It is UL listed but only outdoor. Being used in a porch protected from the elements, I wasn’t sure if that would be considered indoor or outdoor. It wouldn’t be wet but could be damp?
    – user684360
    Apr 3, 2020 at 10:59
  • Usually, the issue with outdoor-only cable is that it isn't fire retardant... Apr 3, 2020 at 23:47

2 Answers 2


The biggest barrier will be physical. 18 AWG solid is much too stiff to solder directly onto LED strips. "The tail will wag the dog" as it were, and the strain placed by the wire on the strip will tend to tear the solder pads off the strip.

I prefer to use #20 or even 22 stranded, however it's fine just to run that for a short 6-12" pigtail. Then transition to the #18.

Remember there is a lot more current on the common wire than the other 4.

  • That makes sense why the cables sold as RGBW extensions are stranded.
    – user684360
    Apr 3, 2020 at 11:01
  • That makes sense why the cables sold as RGBW extensions are stranded. It’s a fairly long run of extension of about 40 feet, that’s why I thought 18AWG may be good to minimize the voltage drop. It’s a 2m length of 24V strip, listed as 12 W / meter. Going to find a stranded wire to use for this. Thank you!
    – user684360
    Apr 3, 2020 at 11:12
  • @user684360 Well bumping up to 18AWG is definitely the right idea. It's not critical it be stranded. 18 AWG stranded will also be too stiff. So I recommend just having the last 6" be #22 stranded, and have the rest be in #18 of your choice. Apr 3, 2020 at 11:59

Using the 18 gauge sprinkler wire with the other recommendation of a pig tail section for transition would be ok, plus since it is rated for outdoor, it would be better than the standard LED wires. The stiffness wouldn't matter, since this is a fixed installation and you would make the appropriate size bend for the wire. The sprinkler wire would be a better quality than the LED wire for using outside. The sprinkler wire would have a separate covering over the other 5 wires.

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