Recommended splice for 6 to 8 ga. wire?

tony_cliffy

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I need to splice some 6 ga. wire to 8 ga. wire on my boat. I can't find any Shrink Tube Butt Connectors in this size. I found some regular Vinyl-insulated Butted Seam Barrel Terminals in 6 ga. that would work and I guess I could shrink some of the adhesive-lined shrink tube around it to keep out the moisture. Anybody have a better idea?

If I use a plain old vinyl crimp butt connector, what size adhesive lined shrink tube should I get to shrink over it but still seal against the underlying 6 and 8 ga. wires?

Thanks!
 

tashasdaddy

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Re: Recommended splice for 6 to 8 ga. wire?

youll have to get the size that will fit over the butt connector, and add a little more heat to shirink the small end.
 

drewpster

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Oct 17, 2006
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2,059
Re: Recommended splice for 6 to 8 ga. wire?

Be sure to use quality shrink tube. There is allot of junk tube out there. Learned my lesson wiring the trailer....twice.
my 2cents.
 

burroak

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Mar 29, 2007
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Re: Recommended splice for 6 to 8 ga. wire?

You may want to look into cold fusion tape. It's used in the utilities (electrical, natural gas). I have found it in Menards,; but an electrical supply house will carry it.
 

JB

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Re: Recommended splice for 6 to 8 ga. wire?

Don't overlook liquid electrical tape for a final seal.
 

bajabassboat

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Re: Recommended splice for 6 to 8 ga. wire?

Alpha shrink tubing is good stuff. Comes in all the sizes and you can go with 6:1 shrink ratio or a 3:1 shrink. You can get it with or without glue. Newark electronics sells it . this link will take you to the newark site for heat shrink tubing . http://www.newark.com/jsp/search/results.jsp?N=0&Ntk=gensearch_001|gensearch_001&Ntt=shrink+tubing|heat+shrink&Ntx=&D=shrink+tubing+heat+shrink
 

Chris1956

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Mar 25, 2004
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27,033
Re: Recommended splice for 6 to 8 ga. wire?

Tony, I would use marine-grade butt connectors and crimp and solder them. Then pull the shring tube over them and shrink it, and cover the edges with liquid electrical tape.
 

Marc III

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Re: Recommended splice for 6 to 8 ga. wire?

LOL at Chris. Are you sure he don't need some conduit too?
 

Chris1956

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Re: Recommended splice for 6 to 8 ga. wire?

Hey Marc, If you don't solder and waterproof the connection, it will fail. I have had a marine-grade battery cable turn to blue paste in less than 4 days, in my saltwater environment.

If he follows your advice, then the question is, "where do you(or he) want to be when that conection fails?"
 

tony_cliffy

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Mar 19, 2003
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Re: Recommended splice for 6 to 8 ga. wire?

How would I solder this thick wire? It is not pre-tinned marine grade wire. The trolling motor manufacturers don't provide pretinned wire.

In a previous job I used to solder much smaller size wire. It seems like it would take a LOT of heat to get the wires hot enough to take solder. The insulation would start melting.
 

drewpster

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Re: Recommended splice for 6 to 8 ga. wire?

Just an FYI, It is my understanding that the ABYC guidelines recommend crimped and heatshrinked connectors. They are specific not to recommend solder. But I cannot remember why. ABYC is the standard that most builders use. Personally I have used both methods when the situation dictates.
 

Chris1956

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Re: Recommended splice for 6 to 8 ga. wire?

Tony, Work some solder paste (flux) into the strands of the wire, and use a 60 watt soldering iron or a propane torch. Just a touch from the torch should do you. Use rosin core solder.

As for the non-recommended use of solder. The crimp-type butt connections are vapor tight and superior to solder, if crimped properly, using the correct tools. Since I have neither the correct tools or the correct technique, I use solder.
 

I/O WALDO

Petty Officer 1st Class
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Nov 16, 2005
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Re: Recommended splice for 6 to 8 ga. wire?

ABYC says no solder cause the wire at the solder point can become britttle from the heat -induced temper and break due to vibration. Solder and seal (shrink wrap and liquid electrical tape)Is the best permanent,LOW RESISTANCE,method of connecting continuous,high current load,unlike wire size splices.(In my opinion and experience.)Done correctly,and secured against flexing(aka vibration)Its forever!
 

Scaaty

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May 31, 2004
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5,180
Re: Recommended splice for 6 to 8 ga. wire?

I just spliced some new batt cables together for my big Merc OB. Home Depot has some aluminum blocks (in the same section with the butt splices)..that are about inch or so long, with a set screw on both ends. I cannot think just what they are called, but come in different sizes for the bigger wire. They are the same things that connect your house wire on the pole to your rain cap somewhere along the line, only those are much bigger. I simply stuffed the stripped wire in there, cranked down the set screw, wrapped in some 1/8 thick rubber I have, taped up good, and zero problems. If it works out in the rain for decades, I see know problem on boats cables if done right​
 

Marc III

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Re: Recommended splice for 6 to 8 ga. wire?

Not questioning your technique Chris. It sounds very thorough. I just thought you were joking about the liquid tape after the heat shrink. I recently bought a boat that had seen some use in coastal VA. Several butt-spliced connections had failed. The wire had become very brittle and corroded. So I agree about sealing the connection in a salt water environment.
 

cjames

Petty Officer 3rd Class
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Mar 23, 2007
Messages
83
Re: Recommended splice for 6 to 8 ga. wire?

Crimp with a good quality butt connector (non insulated) and use the proper crimp tool. Then use good quality shink tube. Marine electricans, and the ABYC may well know something.... As for the use of solder, in addition to the reasons allready mentioned, some solder has a lower melting point than the rating on the wires insulation, you can imagine the problems this could cause.
 
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