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I have an outdoor electronics project which is running 5V DC through 12 AWG wire to power strands of LEDs through 24 AWG wires. The strands are powered in parallel like so:

5V/GND --------------------------------------- ...
          |     |     |     |     |     |
          |     |     |     |     |     |
          |     |     |     |     |     |      ...
          |     |     |     |     |     |
        LED1  LED2  LED3  LED4  LED5  LED6

My first try to get them connected was to use weather proof wire nuts to connect the wires together (so each nut has two 12AWG wires and one 24AWG wire). However, I don't think this is a good solution as these wires will need to be able to move with environmental events (wind, rain, etc.) and it seems like the gross mismatch in the wire gauges will cause the LED power and ground wires to be pulled loose.

I can't make the gauge of the power supply wires smaller since they run over about 50 feet and I don't want to suffer a large voltage drop, and I can't directly make the LED power wires thicker.

So, are there other any good connectors I can use, taking into account the large difference in wire gauges I'm working with?

Nick Alexeev
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wckronholm
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  • Why not vampire taps? – Ignacio Vazquez-Abrams Jun 13 '14 at 19:35
  • @IgnacioVazquez-Abrams Thanks for the suggestion. I had thought of this, but I have been unable to find any which can mate 12AWG wire with 24AWG wire. – wckronholm Jun 13 '14 at 19:41
  • Can't you solder the wires and then put the taps just to protect them? – Vladimir Cravero Jun 13 '14 at 20:55
  • Distributing power at low voltage over long distances is always problematic. Are you sure there's no way to re-architect the system to distribute the power at a higher voltage (and lower current)? Perhaps by putting groups of LEDs in series, or by using local power converters? – Dave Tweed Jun 13 '14 at 21:43
  • Well, they aren't just LEDs but a series of RGB LEDs with ws2801s on them. So, the LEDs have to be wired in serial, but I'm picking up power at regular intervals along the way. Unfortunately, there is no way in this project to re-design the system to distribute the power in another way. – wckronholm Jun 13 '14 at 22:23
  • And also, @DaveTweed, there is no room for local power converters, unfortunately. – wckronholm Jun 13 '14 at 22:49

3 Answers3

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This is to illustrate @WhatRoughBeast's suggestion.

enter image description here

I don't have a 12 AWG wire, so this is a 1:3 scale model. The bigger wire is 20 AWG. The smaller wire is 28 AWG. The butt splice is for 22-18 AWG.

Butt splices for 12-10 AWG are fairly common. It should be able to accommodate a 12 AWG main wire and a 24 AWG next to it.

For outdoors, I would use an uninsulated butt splice (just the metal tube). Then slide adhesive-lined heat shrink over it. When it's heated and shrunk, the adhesive inside melts, fills the voids, and finally cures. This is an efficient method for keeping the water out.

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Nick Alexeev
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  • Dude. Way to go. You might be interested to know that they make butt splices with heat shrink jacket already in place. – WhatRoughBeast Jun 15 '14 at 01:07
  • @WhatRoughBeast Yup. In fact the one in the picture is the kind with heat shrink (on the photo it's shrunk). This one isn't adhesive-lined, but apparently the splices like this but with adhesive-lined heat shrink do exist out there too. – Nick Alexeev Jun 15 '14 at 01:37
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Because 24 ga is so much smaller than 12 ga, I'd seriously consider using crimp butt splice connectors, with the 24 ga tap inserted into one side of the connector before crimping. See https://www.youtube.com/watch?v=pdBcPJ7Dtaw for the type of connector I'm talking about if you don't know already. Once the heat shrink has been activated, the result should be very reliable, and not too much effort to install.

WhatRoughBeast
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  • Thanks for the suggestion. I'm familiar with those types of connectors, but am not familiar with any which will take 24AWG on one side and 12AWG on the other. Do such things exist? – wckronholm Jun 13 '14 at 22:50
  • Not what I meant. Use a 10AWG splice. Put a 12AWG on one side, a 12AWG plus a 24AWG on the other. Or, if you're feeling lucky, see if a 12AWG butt splice will take a 12 plus a 24 on one side. It just might. – WhatRoughBeast Jun 14 '14 at 00:48
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You can use two-part connectors such as Anderson PowerPoles: http://www.hamsource.com/app.html the '30 amp' terminals will take 12-18 gauge wire, and '15 amp' terminals will take 18-24 gauge. The housings for '30 amp' and '15 amp' terminals are the same size, so the connectors will mate to each other. This makes very nice and strong connection.

Of course you will have to buy a crimping tool, but it may be well worth, since the connections come out nice and strong.

The cheaper alternative is 'quick disconnect spade' connectors: . They are made to accept the very wide variety of wire sizes.

theamk
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