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Author Topic:   Small wire to big wire connection
surfkast posted 11-16-2005 02:49 PM ET (US)   Profile for surfkast  
What's the best way to join a small wire to big wire?

Step-down butt connectors or soldering?

The gps power wire looks tiny compared to the 14 guage power wire. Thanks for any replies.

BW23 posted 11-16-2005 03:46 PM ET (US)     Profile for BW23  Send Email to BW23     
I would do it either of 2 ways.

Using a step up/down butt type connector.

Or use a Blue Sea,
Terminal Block 30 Ampere 8 Circuit
PN: 2508

Euro Style Terminal Block 27 Ampere 4 Position
PN: 2804

Chuck Tribolet posted 11-16-2005 05:17 PM ET (US)     Profile for Chuck Tribolet  Send Email to Chuck Tribolet     
Let's get the big picture here.

Where's the 14 gauge wire coming from?
What boat?


LHG posted 11-16-2005 05:38 PM ET (US)     Profile for LHG    
Here's an unorthodox but HIGHLY effective way of doing it if you want a permanent connection:

Use a plastic wire nut of appropriate size, twist the two wires together in the conventional wire nut method. Then fill in the "cup" flush with "Life Seal" polysulfide caulking or similar. This also works GREAT on trailer wire connections, or bilge pump connections that may be underwater or get wet, and is completely waterproof.

On my boats, I wiring all my electronics using the 2 prong flat (trailer style) connectors, which come with about 8" 16 ga lead on each end, which I butt crimp. Then when I need to remove the item for service, or whatever reason, it just unplugs. I do this on all bilge pump and float switch connections also. Makes replacement easy.

derf posted 11-16-2005 06:19 PM ET (US)     Profile for derf  Send Email to derf     
Wire nuts make good connections. Another good method is the one-sided butt splice things. They are like butt splice connectors but only have a hole on one side. You twist the wires together and insert them into the hole and crimp. Then seal it up and you have a good connection.
surfkast posted 11-16-2005 06:21 PM ET (US)     Profile for surfkast    
Thanks for the replies. Here's the bigger picture: 170 Montauk, connecting a Garmin 198c (red/black wires appox 22 gauge though they don't say) to larger pre-wired red/black pair 14 guage wired to the stereo switch by the manufacturer. --all inside the console. The Garmin power wires are only about 6 inches long.
Chuck Tribolet posted 11-16-2005 07:55 PM ET (US)     Profile for Chuck Tribolet  Send Email to Chuck Tribolet     
Your Montauk has an Aux Switch. The GPS should be wired to
the switched side of that. There are a couple of ways of
accompishing that. One is to use piggy back quick disconnect
connectors. Another is to route the switched side to a
terminal block of some sort. I did the former initially,
eventually switched to the latter. Blue Sea is a fine brand.

For the crimp ons and such, Ancor is the brand. Get the
ones that have hot-melt-glue-lined heat shrink. They
may be a bit hard to find for small wires.


jimh posted 11-16-2005 09:49 PM ET (US)     Profile for jimh  Send Email to jimh     
It is a very bad practice, and particularly so on a boat, to join wires together in mid-air using any kind of slice or wire nut. Wherever possible you should avoid splices in wires.

In the case of connecting the power lead to a GPS, bring the lead to a terminal and connect it there. The terminal can be on a switch or on a terminal strip. If the leads from the device are not long enough to reach the switch or power terminal strip, use a local terminal strip and terminate the wires there. Then extend the wires to the switch or terminal strip.

If you must make a splice, use a proper butt splice connector with heat shrink sealing. Secure the cable with clamps so that it is not dangling in the air and subject to vibration and movement.

All that said, these requirements are often overlooked in recreational boats.

Chuck Tribolet posted 11-16-2005 10:12 PM ET (US)     Profile for Chuck Tribolet  Send Email to Chuck Tribolet     
Solder and heat shrink sealing should be at least as good
as the butt joint connector.


kingfish posted 11-17-2005 08:34 AM ET (US)     Profile for kingfish  Send Email to kingfish     
And for another $0.02 from the peanut gallery-

I am also a big believer in the cemented heat-shrink butt connectors (both Ancor and Waytek), and I have had good success on mating wires of different gauges with these, if the wires are close to similar sizes. I have done so by baring twice the needed length of copper on the smaller wire and bending the copper back upon itself before inserting it into the butt connector, for a double thickness or even on occasion baring three times the length and bending the copper back and then forward for three thicknesses before inserting it. Probably not the solution for the absolute purist, but it has served my purposes well, *especially* in a short term fix. (And a professional grade ratcheting crimper is a must!)


davej14 posted 11-17-2005 11:31 AM ET (US)     Profile for davej14  Send Email to davej14     
If you decide to use wire nuts, use the gel filled variety. They are literally waterproof because the gel will displace water and completely encapsulate the connection. Much better than gooping up a standard wire nut with some type of sealant.

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