Importance of "Marine" rated wire

[philwsailz]

132575328_AWjoaGIo.jpg

Seems that the shear stress imparted on the strands by the crimp could potentially exceed the yield strength of individual strands and cause failures. In a high cycle fatigue situation, the cyclical bending loads applied to the crimped end of the wire would likely cause individual strands to part (particularly those on the OD of the bundle) that are at or near the limits of their yield strength due to the shear stress imparted by the crimp. When the connections are soldered, the load is spread among several of the strands and there is no shear stress imparted by the crimp so it seems that this would be a more robust connection.

If the element of human error is removed from the failure statistics, one would expect the soldered connections to outperform the crimped connections.

A proper crimp will never introduce shear. It is a wholly compressive application of force. Take a 3/4" piece of copper tube. Stick your finger in it. Now put the tube in a vise and start cranking. Your finger is not cut off, it is crushed. This is a fairly accurate analogy, except that your finger will not cold work into a polishable homogenous mass like is shown here

[Dandy]

This company does a pretty decent job of offering quality wire, tooling and terminals. They carry decent stock levels and ship quick. We use them for odd connections for custom builds at work.

http://www.waytekwire.com/products/

[SBM1234]

Rather than blindly following my advice, take a look at this 4-page site, heavy on pics, light on print. This gives you an excellent background into what and why...

http://www.pbase.com/mainecruising/w...ination&page=1

The author is one of the guys who I consider as an expert on the subject. I do not hav ethe $6K wirth or crimp tools he does, but after reading this, I think you will be able to form a pretty educated decision.


Phil
Kicker

A guy who writes that the corrosion risk is increased when using solder doesn't seem to me to be an expert, but I digress.

[SBM1234]

Are you removing the human factor from both connections types or just the crimped? Lots can go wrong with a human soldered joint as well.

Agreed 100%. The assumption was that we remove the human error from both.

And we are not taking into consideration the secondary effects of soldering - burnt carpet, blisters on skin, etc.

[chpthril]

Seems that the shear stress imparted on the strands by the crimp could potentially exceed the yield strength of individual strands and cause failures. In a high cycle fatigue situation, the cyclical bending loads applied to the crimped end of the wire would likely cause individual strands to part (particularly those on the OD of the bundle) that are at or near the limits of their yield strength due to the shear stress imparted by the crimp. When the connections are soldered, the load is spread among several of the strands and there is no shear stress imparted by the crimp so it seems that this would be a more robust connection.

If the element of human error is removed from the failure statistics, one would expect the soldered connections to outperform the crimped connections.

Are you removing the human factor from both connections types or just the crimped? Lots can go wrong with a human soldered joint as well.

I agree that fine stranded wire can be over crimped. But a quality tool will reduce this.

[philwsailz]

Okay, so to be fair, for most of my crimps, I am using the heat-shrink crimp connectors using this Klein tool:

http://www.alliedelec.com/klein-tools-1005/70145387/

I don't use these for cutting though. I have a different tool I use to cut wire.

[philwsailz]

Rather than blindly following my advice, take a look at this 4-page site, heavy on pics, light on print. This gives you an excellent background into what and why...

http://www.pbase.com/mainecruising/w...ination&page=1

The author is one of the guys who I consider as an expert on the subject. I do not hav ethe $6K wirth or crimp tools he does, but after reading this, I think you will be able to form a pretty educated decision.


Phil
Kicker

[SBM1234]

Seems that the shear stress imparted on the strands by the crimp could potentially exceed the yield strength of individual strands and cause failures. In a high cycle fatigue situation, the cyclical bending loads applied to the crimped end of the wire would likely cause individual strands to part (particularly those on the OD of the bundle) that are at or near the limits of their yield strength due to the shear stress imparted by the crimp. When the connections are soldered, the load is spread among several of the strands and there is no shear stress imparted by the crimp so it seems that this would be a more robust connection.

If the element of human error is removed from the failure statistics, one would expect the soldered connections to outperform the crimped connections.

[viking]

I have crimpers that are significantly better than the cheapos you find in the automotive electrical section at Walmart...

Know there are as many bad solder joints as there are crimps. Proper tools are key. Get a good crimper and you are likely to make good connections that are going to be superior to a solder joint. You will probably be quicker at getting to a point where you are making good joints when crimnping compared to soldering.

Phil
Kicker

Phil,
On the topic of a good crimp tool! Can you give some guidance as to what tool might be a good choice for home use that won't break the bank? I'm currently shopping for one as I type!!

[philwsailz]

Funny thing. The USCG and the ABYC do not allow soldering for any terminations on a boat. They also do not allow single-strand conductors on a boat. Here is how these two points tie together. Think about ROMEX home power wiring. Single-conductor stuff, right? Not very flexible. If put into a dynamic situation you run the risk of work-hardening a bend-point in the conductor and breaking it. Poof, fire. Similarly, when you solder cable, MOST OF THE TIME you are wicking the solder up into the stranded wire some distance from the solder connection. As a result you end up with a section of wire that is in effect a single conductor... This section of wire is now stiff and inherently brittle. As a result it is much more likelly to break due to bending motion. Stranded wire remains flexible, and stranded wire that is crimped in a connector remains flexible going into the crimp.

I maybe sit on the fence on the topic, even as an ABYC and NMMA member. I personally will solder my battery connections, following with heat shrink. I use a heat gun to do the soldering, and the process I use wicks very minimally into the cable outside of the terminal lug. Why do I solder? I don't have a nice big #4AWG wire crimper, so soldering is going to give me a better joint when compared with stuffing the wire into a terminal and whacking it on the floor with a big hammer... For speaker and other connections I try to use the heat-shrink crimp connections. I have crimpers that are significantly better than the cheapos you find in the automotive electrical section at Walmart...

Know there are as many bad solder joints as there are crimps. Proper tools are key. Get a good crimper and you are likely to make good connections that are going to be superior to a solder joint. You will probably be quicker at getting to a point where you are making good joints when crimnping compared to soldering.

All that being said, keeping the cable flexible is the reason why soldering is not allowed for marine electrical connections.


Phil
Kicker

[SBM1234]

I solder everything I can. I'll even solder the ends of the wire that plug into the amps. Sure, it's a bit anal, but it makes troubleshooting so much simpler when you can trust your connections.

[chpthril]

Do car manufacturers solder their battery cables? Does Tigé? I really don't think it is necessary.

Sent from my Passport

I thinks its a matter of speed and easy of assembly when looking at pre-made cables. Much more efficient to insert the cable into the lug and then place it in an industrial crimper thats pre set for the right amount of force. When building your own custom cut cables, different story. It can be done with either a common butane torch or heat gun and can do any size cable/lug. Done right, you will likely never have a failure. Ive seen my share of crimped cables pull loose over time. On both cars and boats. But, a good crimper will make a good termination, but not a hammer and a punch or similar harbor freight crimper that does a simple dimple.

I solder all my battery cables and many of my other terminals.

[dom w. forte]

If you own a high dollar crimping machine that compresses the crimp 360 it will work fine, but if its just the ussual dent in one spot type of crimp it is better to solder.

[JohnnieMo]

Do car manufacturers solder their battery cables? Does Tigé? I really don't think it is necessary.

Sent from my Passport

[boatwakes]

I would recomend that the battery cables also be soldered , crimps increase resistance and also come loose with heat and expansion.

X2