Butt Splicing from Battery to Engine??

[George1632]

I just had an new engine installed and noticed that there was a "butt splice" between the engine breaker (coming off the battery) and the engine. Can someone tell me if this meets ABYC standards?

Thanks in advance.

[pcmm]

Is it a butt splice or maybe a fuseable link ( a built in fuse)? If it s a regular butt splice I personally would get rid of it ABYC or not.

[George1632]

It is a butt splice. Intuitively, I know it has to go but just wondered if it was approved as it opens questions about the rest of the work.

[David M]

A butt splice has the potential of creating a point of resistance in a wire run which would cause a voltage drop in the wire. Worse yet, it has the potential of pulling apart causing a short or even a fire.

Ideally, you want to replace the wire so as to have a continuous run.

[Frankly]

Give us a little more info about engine, breaker, and wire size. Not ideal situation, but if replacing the entire wire length is going to be a big deal then might be one of life''s compromises. I spliced the wire leading to my anchor windlass 14 years ago and has worked out fine, and I am as anal about electrical stuff as anybody body on this planet.


Frankly

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[George1632]

57 HP Yanmar and I believe it's a 40 amp breaker but not certain as I'm not on the boat. Can't tell about the wire size either but it runs from the battery box over the opening to the through hulls and to the engine.

[sailorboy1]

I fail to see why a properly done butt slice would be any more of a problem than a cable end fitting. As long as it’s well sealed to prevent corrosion I wouldn’t have an issue with one on my boat.

[wingless]

Welcome to the forum.

Yes it is possible to implement a butt splice on a battery cable, from 2/0 to smaller, using readily available Ancor heavy-duty butt connectors.

The frequent issue is crimp tools. This reply shows one of my thick wire crimp tools that will properly crimp 4/0 to 8 AWG wire connectors.

The ABYC standard defined the static load that the connector must withstand for one minute. For the larger wires these are well over 100 lbs. An improperly-crimped connection will not satisfy this important requirement.

[mjscottinnc]

In many respects it depends on the quality of the materials, workmanship and intended use. In certain environments a butt splice is completely acceptable, while other's are not. Based on a 40 amp breaker it would have to be a properly sized hydraulic or ratcheting tool crimp for me to be comfortable. Wire needs to be marine grade (tinned). Opening up the insulation midway means possible water infiltration and corrosion, unless its a water proof butt connector.

[GordMay]

Every connection (termination OR splice) is a potential point of failure, and a definite source of increased resistance (minute but present).
Unnecessary connections are an unforgivable, even if minor, mistake in any new installation.
A butt splice, in a new boat (or new installation), is very poor trade craft, and indicative of low quality standards.

I know of no ABYC prohibition against splices.

[Boatyarddog]

Originally Posted by George1632

57 HP Yanmar and I believe it's a 40 amp breaker but not certain as I'm not on the boat. Can't tell about the wire size either but it runs from the battery box over the opening to the through hulls and to the engine.

A butt splice on a battery cable is not optimum, but if done correctly is not a problem, or out of ABYC guidelines.
On a 40 amp circuit, it's not a battery cable, only a wire feeding a load.
Not a problem, if it looks suspicious, or isn't crimped and covered correctly.
Then by all means replace it.
Cheers,
SV Cloud Duster

[bharney]

A butt splice should be ok if done right, however it would be better if you soldered the connections also and used a good splicing tape to cover it. I've heard that you should not crimp and solder the same connection but I've been doing it this way for decades and never had a problem.

[john61ct]

No, if the crimp is done correctly

quality wire fittings & tools, cold-welded gas-tight would pass a milspec pull test,

then adding solder contributes nothing good.

Not saying a good solder-only connection can't be nearly as good, but takes a much higher level of skill to do those consistently reliably.

[Stu Jackson]

Not a single question about what service this wire performs and whether or not it is properly fused at the battery end? Unless I missed it...

[wingless]

Originally Posted by George1632

I just had an new engine installed and noticed that there was a "butt splice" between the engine breaker (coming off the battery) and the engine.

Originally Posted by Stu Jackson

Not a single question about what service this wire performs and whether or not it is properly fused at the battery end? Unless I missed it...

According to the OP there is a breaker "coming off the battery" and this is for the engine.