I am wanting to join a #8 awg wire to a #4 awg wire. (for my trolling motor and outlet)

I am trying to come up with the best way to do this.  with it being two different wire sizes, i'm struggling to find a for sure method.

 

I looked at the anderson plug, but those look like they only work for similar wire sizes (in and out)

I see the screw type barrels where you slide the wire in, and then tighten the set screws down, followed by shrink tubing

I also see the option of buying a barrel and crimping it down, followed by shrink tubing.

 

since I am dealing with two different wire sizes, I need some help.

what's the best way to join these two wire sizes?

The absolute best method is to solder them together and put shrink tubing over the joint (preferably the stuff with the hot melt sealant in it for extra protection). 
 

 

It takes good skills to do a thoroughly well done solder connection with wire that size, not to mention a hefty 100 watt iron.

 

They do make splices for these wire sizes

 

https://www.pacergroup.net/nylon-butt-splice-8-4-awg/?srsltid=AfmBOoqgqJLG4E2c972fyKEB55ur-wkQwMWFLQoTZ_tOob0sh0ArFMH3

 

Car stereo guys use these

 

https://www.aliexpress.com/i/3256805703418407.html?gatewayAdapt=4itemAdapt

 

Home depot has these

 

https://www.homedepot.com/p/Commercial-Electric-6-AWG-to-4-0-AWG-Dual-Rated-Splicer-G61104/310741755?MERCH=REC-_-pipsem-_-303578399-_-0-_-n/a-_-n/a-_-n/a-_-n/a-_-n/a

 

https://www.homedepot.com/p/Commercial-Electric-14-AWG-to-2-0-AWG-Dual-Rated-2-Port-1-Sided-Entry-Insulated-Multiple-Tap-Connector-Black-G60005A/324050827?MERCH=REC-_-pipsem-_-303578399-_-1-_-n/a-_-n/a-_-n/a-_-n/a-_-n/a

@FloridaFishinFool - this might be another one of those "overthinking it" situations.  I have seen plenty of the screw down connectors like what you show. Maybe that's all I'd need, but the two different wire sizes needing to be joined are making me nervous.  

 

If it's as simple as insert, screw down, and shrink tube it....then I need to stop thinking 😄

If a 4 will fit in there. A 6 will fit in there. And an 8 will fit in there. All you gotta do is make sure its a good tight connection. Crimps are adjustable. Screw downs should also be adjustable for various wire sizes.

 

Just do your homework on the connectors and be careful. Make sure connections are tight and clean. And thoroughly insulated afterwards.

 

I like to use something on the wires to prevent corrosion, and twist the ends some to make a nice compact wire to tighten down on.

Ive heard about di-electric grease. That seems popular for that task

I would suggest considering some form of strain relief at a butt joint, especially if the wire will be subjected to movement. Stripping the insulation from the wire to put into the butt joint reduces that since insulation provides some degree of strain relief in addition to the insulating properties. I often use two layers of shrink tube with that being one of the intended benefits. I have the second piece overlap the ends of the first layer so it's gradual.

How about ring terminals on the wires and use a junction block.  If you ever need to add additional circuits you can do it easily.

4 hours ago, jbrew73 said:

How about ring terminals on the wires and use a junction block.  If you ever need to add additional circuits you can do it easily.

I used those exact same junction blocks under the bulkhead to wire my new Ultrex Quest. I used a hydraulic crimper to cold weld the ring terminals to the cables.

You can also fold the thinner wire once or twice to make it the same size as the thicker one and use a butt splice.