Joining larger gauge wire to 2 smaller gauge wires?

[BrettB]

What's the proper way to join a larger gauge 12v wire to 2 smaller gauge wires?

I notice one of my head pumps was not working in my new-to-me boat. It appears these 3 wires(the black ones) lost their tape, started separating, and then started smoking.

Looks like i need to fix up the other wires too... Fortunately, the wiring in the head looks immaculate.

Thanks in advance!

[redsky49]

Not entirely sure I understand your question, but I will try to offer some suggestions.

For the two smaller wires, you can always twist together the two wire leads. Use a butt connector to attach to the larger wire. If there is a real discrepancy in size between the two twisted conductors and the single larger conductor, look for butt connectors that have different size openings, purpose built to allow connecting wires of different gauges. These are known as 'step-down' connectors.

Is this what you are asking?

[Stu Jackson]

They make step down butt connectors. Look at any chandlery website in the electrical section.

[Jammer]

The various alternatives have their drawbacks.

In general, I try to use a crimp-type butt splice (designed for two wires of the same size) and a ratchet crimper. The two smaller wires go in one end, the larger goes in the other. It will always work if the smaller wires are two sizes smaller than the large wire (like a #10 and two #14s, or a #12 and two #16s), and will sometimes work for differences of one or three sizes (#12 with two #14 will work but #10 with two #12 will overfill the connector, for example). It may be necessary to strip the smaller wires back a little farther than usual, and it doesn't hurt to put heat shrink tubing over the whole thing when done.

There are terminal blocks designed for the situation but these are supposed to be mounted to something. They have the advantage of allowing individual wires to be disconnected for troubleshooting, refit, or repair. There are many styles, but here's one of the more useful ones:

https://www.automationdirect.com/adc...ries)/HPB106-1

Another alternative is to solder the wires and cover them with heat shrink. This works well for smaller wires, and can work OK even for battery cables if you have a large enough soldering iron to do the job properly. It takes skill and the proper kind of solder. In a high-vibration, high-current environment, crimp connections are supposed to be more reliable but my experience has been that either will work just as well if made properly.

[BrettB]

Looks like it is two 8-10 gauge wires and one 4 gauge wire.

[toddster8]

Note that the circuit should be fused for the smallest wire or component.

I think a terminal block is the preferred method of joining here. When the equipment needs to be removed, the terminal is unscrewed, rather than cutting the wire.

[smac999]

With those sizes you need a single post or bus bar. Each cable with a lug