I want to extend a couple of electric wires coming out of a ceiling to get to a hole at the top of a lighting fixture. Let's assume for the sake of discussion the lighting fixture is fixed and will not be moved, rotated etc.

I'm used to this kind of wire connectors:

enter image description here

(obviously I'll need just two 1-to-1 units in this case.)

and I could use those - except that I don't have enough cross-section for them. The wires will be located between the top surface of the lighting fixture and the ceiling, and will not have more than a few millimeters of spare height. Here's how it looks (black blob is the hole):

enter image description here

How do I connect the wires in a stable fashion, hopefully without too much fuss? Are there special thin-profile connectors I could get?

PS - I live in Palestine/Israel in case that matters w.r.t. tools/equipment available to me.

  • Can you not fit some sort of box into the ceiling that the fixture can mount over? Jan 19, 2019 at 19:40
  • @ThreePhaseEel: You mean, carve out a disc out of the ceiling, fit a disc-shaped box, and mount the fixture onto that? No can do... that's overkill.
    – einpoklum
    Jan 19, 2019 at 19:44
  • "overkill" Eh? Gotta put splices in a box (at least over where I am) Jan 19, 2019 at 19:53
  • @ThreePhaseEel: How about: A small hole into the ceiling, just large enough to fit the connector, but small, so that it's easy to create and doesn't interfere with fixing the fixture to the ceiling?
    – einpoklum
    Jan 19, 2019 at 20:05
  • Crimps and heatshrink is often considered the same as unjointed cable, and can go wherever you want them. Jan 20, 2019 at 9:58

3 Answers 3


Use a crimp joint with heatshrink

Join the wires with a crimp. This is a permanent means of connecting wires that, done properly, will never come loose. It involves crushing another piece of metal into the wire with a special tool.

It is, however, critical that you use the correct size crimp for your cable, and the correct tool. Test the crimp by trying to pull it apart - they should hold at least 5-10kg force.

Insulate with heat shrink tubing. This is a special type of tubing that can be slid over the cable then heated, causing it to shrink radially and seal onto the wires/cables. Ideally you would use one sleeve over each individual crimp/conductor, then another larger diameter layer over the sheath of the whole cable (assuming you are joining sheathed cable).

Apply heat using a hot air gun or blow torch - avoid applying too much heat.

The shrinking effect prevents the sleeve from moving, and reduces any gaps. Glue lined heat shrink is available if the joint needs to be watertight.

GIF of heatshrink

Image courtesy Smial of Wikipedia under CC BY-SA 2.0 DE.

  • Blow torch? Seriously? ... Don't you mean blow dryer? +1. Now I just need to find these things. Is the black connector you linked to the kind which you suggest I use, or is the image just an example of heat-shrink tubing?
    – einpoklum
    Jan 20, 2019 at 11:46
  • Not sure if a blow dryer gets warm enough. Yes, a butane blow torch works. The image is only to show the red heat shrink; those black plugs are only good for lo-power electronics Jan 20, 2019 at 12:21
  • I would use crimps like these, but for the right size cable. They can be used with the crimper found in many electricians' pliers. Jan 20, 2019 at 12:22
  • Yeah -- a butt crimp splice with heatshrink over the top is probably the least-bad option here given that installing a box seems to be out of the question Jan 20, 2019 at 15:19

Wow, I am with @threephaseeel. Pretty sure Israel is 230vt for household current which would likely make mandatory that electrical connections are enclosed in an approved electrical box.

Please look into at least finding a shallow electrical box you could mount on the surface of the ceiling, to contain the wire connection. You could then mount the light fixture to that. Yes, it would hang down a bit and maybe would not be as pleasing to look at, but better than a fire which burns down your home (which also would be less than pleasing aesthetically).

  • I don't quite see how a shallow box is different than the "box" made up of the ceiling and the top surface of the light fixture. Are you suggesting it might heat up? Regardless, I'll give some thought to creating a small cavity in the ceiling to hose a proper connector. And even more thought to having a professional handle the issue.
    – einpoklum
    Jan 19, 2019 at 22:06
  • @einpoklum -- a proper electrical box is tested to not catch alight if a splice inside it puts on a fireworks show ;) Jan 19, 2019 at 22:15
  • @ThreePhaseEel: My ceiling won't catch alight (all construction here is concrete, not wood); nor will the top metal cover of my light fixture. Now, technically, a spark could fly out the crack between the ceiling and the fixture, and land on something flammable; but this will be taken care of by the very light filling of the crack wich I plan to do, to avoid light bleed from the top of the fixture. Either that or the metal will bend slightly and block the crack anyway.
    – einpoklum
    Jan 19, 2019 at 22:31

My fallback solution will be, for each wire:

  1. Getting some extension wire
  2. Stripping the ends of the extension wire
  3. Braiding the stripped end of the existing and the extension wires together
  4. Soldering the braid (Difficult, since I would have to work near the ceiling).
  5. Applying a good few rounds of electrical tape:

enter image description here

(Sorry about the lack of images for the other steps...)

But I dislike this solution because it's very involved and I'm not sure about the strength of this arrangement against pulling (which I don't plan on of course). A different solution which improves on this would be much appreciated.

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