Connecting Different Size Wires

[minuteman62-64]

I know for marine applications the preferred way to connect wires is with crimp connectors. I've had good success (i.e. zero failures) with crimping same-sized wires (#16 to #16) and close to same-sized wires (say #16 to #18). However, I have problems with a difference of more than one wire size.

I'm connecting #16 wire to wire quite a bit smaller (looks to be either #20 or maybe even #22). I've been soldering wire all my life (at least from pre-teen on) and am much more confident in soldering these two wires than I would be with a crimp connector.

What would be the issue(s) with soldering these connections, heat shrink tube over and then covering all with the liquid tape compound?

The connections would be to a sensor mounted on the cylinder head. Consequence of failure would be loss of an add-on overheat alarm.

Or, is there a technique for crimp connecting different size wires that I should be following?

 

[bruceb58]

Re: Connecting Different Size Wires

I am a major crimp fan but I would just solder and use heat shrink that has adhesive in it. If you use the smallest heat shrink that would cover the 16 ga wire, it may be able to shrink over both sizes.

As far as crimps are concerned, they are way more preferred over soldering where there is a rigid connection that will be affected by vibration like a ring connector.

 

[matt167]

Re: Connecting Different Size Wires

Yea, I would just solder that connection. Strip more than you need to from the smaller size and just wrap it good and tight, then solder. As for crimps, I generally hate them, but in a high vibration environment, use the nifty shrink tube crimp connectors..

 

[UncleWillie]

Re: Connecting Different Size Wires

I would take the Solder connection any day.
The Crimp connection is generally going to be more reliable than a solder connection made by the average person who has little to no experience in soldering. Cold joints follow.

If you know how to solder, go for it. If you need instructions in soldering, crimp it.
A similar situation comes up in the Weld vs. Bolt question. The weld is better 90% of the time.
99% of the population can not weld, but they can handle a wrench without hurting themselves.
10% should not even own tools!

 

[MH Hawker]

Re: Connecting Different Size Wires

If you really need to you can strip a good bit more of the insulation off and double or even triple bend the wire so it fits snug into the crimp connector.

 

[Silvertip]

Re: Connecting Different Size Wires

I too will solder and double heat shrink the connection on wires that small. Butt splices are big, bulky and unless you stagger the connections you end up with a great big bulge in a harness. Besides, heat shrinks is a good strain relief. I also tend to remove the plastic from a crimp terminal and then solder the connections. Again, two layers of heat shrink about twice the length of the original plastic sheath acts as a good strain relief and eliminates bulk from stacked connections. The application, wire size, and termination type all play into how you make a connection.

 

[Auger01]

Re: Connecting Different Size Wires

anchor makes a crimp connector just for crimping different sizes of wire:

ANCOR MARINE Connector at West Marine

 

[bruceb58]

Re: Connecting Different Size Wires

If you really need to you can strip a good bit more of the insulation off and double or even triple bend the wire so it fits snug into the crimp connector.

You never want to do this.

 

[icyveins]

Re: Connecting Different Size Wires

I used to be an electrician building firetrucks, 99% of the time when we had to make a small to large connection we would take and strip the bigger wire back and take our test light and push it through the the center of the larger wire creating a hole..... then take your smaller wire and feed it through the hole and then wrap around the larger wire....add solder if needed

 

[kahuna123]

Re: Connecting Different Size Wires

Add the right size shrink wrap to the smaller wire to build up its diameter. Double the length you strip it. Double that over and stick it in the shrink connector. Crimp then together and heat the shrink connector. Bingo its done.

 

[bruceb58]

Re: Connecting Different Size Wires

You can never get a proper crimp by doubling back a wire onto itself. Same reason you don't put 2 wires into a crimp connector.

 

[hall832]

Re: Connecting Different Size Wires

You can never get a proper crimp by doubling back a wire onto itself. Same reason you don't put 2 wires into a crimp connector.

I get the reason you wrote doubling back a wire onto itself but. No disrespect intended here. I see 2 wires into the same connector and crimped into eyelets on Mercruiser & Optimax from the factory.

 

[hall832]

Re: Connecting Different Size Wires

I love heat shrink but connectors.

 

[kahuna123]

Re: Connecting Different Size Wires

I have done this once or twice

 

[fishrdan]

Re: Connecting Different Size Wires

You can never get a proper crimp by doubling back a wire onto itself. Same reason you don't put 2 wires into a crimp connector.

That's what solder is for (joking...)



I to have seen double wires crimped into the same connector in "factory" built harnesses,,, not that this is the proper way to crimp on a terminal end.

Here's something that I have done, not that it's a perfect way, but... I found a butt-crimp connector big enough to fit both wires inside side-side, melted off the connector insulation, knocked out the center "wire stop" and inserted each wire completely though the butt connector,,, crimp, solder, couple layers of heatshrink.

like this
------------------------------
-------------------------------
----------------------------------------------------------------
------------------------------

small wire/butt connector/big wire

 

[bruceb58]

Re: Connecting Different Size Wires

I have done this once or twice

I have as well. I have worked with assembly/manufacturing for military/automotive/commercial and you never double back a wire in a crimp connector.

 

[hall832]

Re: Connecting Different Size Wires

Nice work on that 1978 Glastron Sportster, Auger01 just checked out your complete rebuild. artwork with the electrical.

 

[bruceb58]

Re: Connecting Different Size Wires

That's what solder is for (joking...)

Going back to what the Op wants to do, soldering is perfect here.

 

[MH Hawker]

Re: Connecting Different Size Wires

You never want to do this.

And like I said ,,if you really need to. Its not all ways a perfect world where ever thing is handy.

 

[fishrdan]

Re: Connecting Different Size Wires

Going back to what the Op wants to do, soldering is perfect here.

Agree, soldering is a good way to make that connection for our DIY crowd here. Though, I'm very cautious of making a good strain relief over a soldered connection, with several layers of heat-shrink tubing as ST mentioned.

I found a broken "factory crimped and soldered connection" in my boat's engine wire harness, 8" from the plug, 1 wire in - 2 wires out, no support, right on a bend that vibrates a lot with engine movement. When I found the solder infused wire broken off right at the crimp connector, I thought,,, What were they thinking!...