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connect 18g wire to 16g

Posted: Sun Oct 20, 2019 9:06 am
by DrBryanJ
I bought mostly 16 gauge wire to use. I didn't get any 18. My bilge pumps came and they have 18 gauge wire. How do I connect the 16 gauge from my switch to the 18 gauge on the pump? Connectors available are for 18-22 or 14-16. Which should I use? Are there other connectors available that I am not finding?

Re: connect 18g wire to 16g

Posted: Sun Oct 20, 2019 9:43 am
by Bill Edmundson
Bryan

The 14-16 is probably fine. If you are still concerned, there is heat shrink tubing at the big box store that can go over the entire connection.

Bill

Re: connect 18g wire to 16g

Posted: Sun Oct 20, 2019 9:49 am
by DrBryanJ
I found these https://www.pacergroup.net/bullet-connectors/. I could put the male on the 18 and female on the 16 and heat shrink over the entire connection.

Re: connect 18g wire to 16g

Posted: Sun Oct 20, 2019 11:39 am
by neel thompson
Bryan......I'm with Bill on this one... Use the 14-16 connectors. When I have done this, I strip enough off the 18 ga. wire so the tin wire can be bent over to make it thicker. Then after you put it all together and heat up the connector, both ends will seal up

Re: connect 18g wire to 16g

Posted: Sun Oct 20, 2019 4:03 pm
by kens
The correct answer is a reference to "circular mil area"
That is, the diameter of a wire has a cross section area, and that said cross section area has a correct size crimp for that.
In order to crimp a small wire into a larger crimp barrel, the easiest and most common, is to add filler wire to the small wire and crimp it into the larger barrel.
For something like 18ga into 16ga barrel, find some 20ga wire and add 20ga+18ga = crimp that into 16ga barrel, trim off excess 20ga hanging out.

For a lack of 20ga filler, take some spare wire , add enough few strands to the 18ga until it equals size of 16ga, crimp it into 16ga barrel, trim off excess.

Re: connect 18g wire to 16g

Posted: Sun Oct 20, 2019 4:43 pm
by kens
DrBryanJ wrote:
Sun Oct 20, 2019 9:49 am
I found these https://www.pacergroup.net/bullet-connectors/. I could put the male on the 18 and female on the 16 and heat shrink over the entire connection.
Yes, I see that would work, but if you were to remove your outer covering of heat shrink, and re-assemble it all according to color codes, they would not match up. The color codes would not align, if that matters, you would have red/mating to blue.

Re: connect 18g wire to 16g

Posted: Sun Oct 20, 2019 6:53 pm
by Hercdrvr
Hi Bryan,
I’d use a 16G connector and strip the 18G wire far enough back to double it over to fill the connector.
Matt B

Re: connect 18g wire to 16g

Posted: Mon Oct 21, 2019 3:51 am
by DrBryanJ
Thanks guys for the replies. Several good options.

Re: connect 18g wire to 16g

Posted: Mon Oct 21, 2019 3:58 am
by DrBryanJ
Just as an aside: If the smallest wire allowed on a boat is 16g unless the 18g can be bundled with other wires, why do many electrical items for boats come with 18g wire? I think my problem would come up often.

Re: connect 18g wire to 16g

Posted: Mon Oct 21, 2019 4:41 am
by Biss
You could just solder the connection and use heat shrink tubing...

Re: connect 18g wire to 16g

Posted: Mon Oct 21, 2019 5:02 am
by DrBryanJ
I believe soldering can not be the sole source of connection.

Re: connect 18g wire to 16g

Posted: Mon Oct 21, 2019 7:17 am
by chugalug
:D I used one of those racheting crimpers for marine use.A torch was too hot so got one of these matches
IMG_1214[1].JPG
works good :lol:

Re: connect 18g wire to 16g

Posted: Mon Oct 21, 2019 8:35 am
by steveh41
Neels method has worked for me. Some LED indicator leads are as small as 20ga, just strip enough insulation to fold the bare end until you get the right size for the crimp. The connector heat shrink may not contract enough to make a seal on the smaller wire so you might need to build up the insulation with a short length of small diameter shrink tubing to get a tight fit.

Steve

Re: connect 18g wire to 16g

Posted: Mon Oct 21, 2019 10:59 am
by Mr Hot Rod
You may want to step up to marine grade connectors and a quality crimper :
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Re: connect 18g wire to 16g

Posted: Mon Oct 21, 2019 3:27 pm
by DrBryanJ
Paul: I am using marine heat shrink connectors. That is the first time I've seen step down connectors. I think they will work great. I'll pick up some. Thanks