I'm interested in lighting a stairwell in my house using a red LED strip.

I have a nearby AC outlet and plan on using a typical 12V power supply from the AC outlet. I know that class 2 wire is typically used for 12V DC applications for running behind walls, but romex wire (Typically behind walls) is usually terminated at an outlet.

If I chose to run my class 2 wire behind the wall, does it have to be hardwired to the LEDs? Is there an outlet that is typically used for low voltage applications such as this?

What is the typical procedure for running wire to LED strips behind walls?

NOTE: This question is somewhat similar to (How can I mount an 12V transformer for LED lighting inside a wall?), but differs slightly in what I'm asking. I've read it, and it my transformer is in a remote serviceable area. My question is more about how exactly the class 2 cable is wired to the LEDs.

  • Where are you in the world? Rules and regulations vary. Certainly make sure that the 12V supply is current limited and has appropriate cooling / a way for heat to escape. Mar 4, 2019 at 16:00
  • If the LED strip is long, the far end will be dimmer due to voltage drop along the PCB traces. May want to run 16ga or larger wires next to it and connect them periodically. Mar 4, 2019 at 16:10

2 Answers 2


Honestly, I solder direct to the LED strips. You have to be careful, because if you select wire that is too stiff, it can tear the pad off the printed circuit board. So I use stranded wire, erring on the side of "small".

Mind you, I do that soldering on the workbench, not on my knees.

  • Soldering is definitely the best if you can do it. Pre tining the pads helps alot and wrapping the gel (if gel type) with a heat sink (I use duct tape) keeps it looking nice.
    – Joe Fala
    Mar 4, 2019 at 3:36
  • I planned on soldering the class 2 wire, but this is done as soon as it emerges from the hole in the wall? Do you know anything about NEC compliance with regards to the issue, or is this just ho it is commonly done? Mar 4, 2019 at 3:49
  • NEC doesn't care if you solder wires onto low voltage <55W equipment. That makes for a very neat, low-profile installation since there isn't any bulky connector. Like I say, I do my soldering on the bench, figure the needed wire length first. Mar 4, 2019 at 3:56

LED strips often use a barrel jack, for 12v it should be 5.5mm. Like this one enter image description here www.falconcomputers.com

The other side will need an adapter depending on the type of LED strip you have.

This is a a 3 wire version enter image description here www.digikey.com

There are many different types and styles. 2 wire are usually one colour and four wire are usually RGB. To find exactly what you are looking for, I would need to know exactly what type of strips you are using. A picture would be helpful too.

For a clean look you can use these enter image description here

enter image description here www.ebay.com

Then insert heat shrink and do a western union splice cutting off any sharp/protruding wires.

enter image description here www.instructables.com

Solder it being careful not to heat up the heat shrink. Move the heat shrink in place and heat the heat shrink.

I always add a larger heat shrink to encapsulate the cable.

  • So a barrel jack is commonly used when it emerges from the wall? Mar 4, 2019 at 3:50
  • One of many options. See also Molex connectors. See also the many LED connectors available at banggood dot com or AliExpress dot com. Mainly choose connectors such that the power-providing connector won't short out if it brushes against a conductive surface. Mar 4, 2019 at 16:05
  • The most important considerations are: adequate for the voltage and current, won't be plugged into something else by accident (unwise to use an AC line plug!), not a fire hazard. Mar 4, 2019 at 16:07

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.