One Way To Splice a Power Cable

[rgsparber]

In most cases, I am splicing a power cable because it has seen rough service. My repair must be at least as strong and safe as the original. Here is how I do it.

If you are interested, please, click here.


Your comments are welcome. All of us are smarter than any one of us.


Thanks,

Rick

[DIYSwede]

-Thanks for the tips Rick, and AFAIK your splice will be at least as strong as the original.
Depending on your local code & applicable regulations,
I'd think the heat shrink & -sheath should be of proper thickness and grade for the applied voltage.
One caveat though when it comes to fatigue strength of soldered joints thru bending forces*.

Personally, I always do staggered splices (even for lo-voltage duty), and use the thickest possible heatshrink for the wires,
build up the missing sheath thickness over the spliced & shrunk wires with self-amalgamating rubber tape,
and finally slipping the heatshrink sheath over, with 2 extra inches of shrink overlap added on each side.
*Thus each wire steadies the others in the tight bundle, and the cable is more prone to bend in the supple cable,
rather than at the relatively much stiffer splice: hopefully offering less risk of fatigue breaks.

But then again - that's just my two precautious cents.

Cheers
Johan

-Yup - even after some 35 years it does happen at times that I forget to put the heatshrink on before soldering...

[DIYer]

Thanks rgsparber! We've added your Power Cable Splicing Method to our Electrical category,
as well as to your builder page: rgsparber's Homemade Tools. Your receipt:

Power Cable Splicing Method by rgsparber

tags: electrical

[desbromilow]

ditto, I use similar methods for all cable splicing (ELV, LV) but once over 4mm2 I use crimped butt splices instead of soldered joints. I picked up a hydraulic crimper off ebay for a decent sum, and it's good from 10mm2 up to 135mm2. 4 and 6mm2 crimps are done with standard electrical pliers (mine have a notch designed in for that purpose.

[Tonyg]

Hi Johan, glad I am not the only one that forgets.

[techcollect]

Thanks for this Rick

The method you show is the prescribed way used by NASA, in house and by their contractors.
One thing they also specify is using clear or translucent shrink tubing on the connections to allow inspection without disrupting the splices in the event there is a question later. This allows visual confirmation to check in event of leakage into splice area that could cause joint corrosion.
This may be helpful in situations where multiple people work on an assembly. (or where we are getting old and leakage from our little gray cells inside is going out gray and our follicular strands are getting silvered. We are looking at opaque tubing thinking, "I did solder that one, didn't I?")

To Johan's reference on strength, testing has shown these joints to exceed the tensile strength of the unsoldered wire.

[rgsparber]

Thanks! I have updated the article with the added credibility. It is now linked to a video demonstrating the Western Union plus pointing to the NASA regulations.

Rick

[katy]

I suggest that you de-oxidize the copper before twisting and soldering it.

[rgsparber]

I suggest that you de-oxidize the copper before twisting and soldering it.

I always use flux. Is that what you mean?

Rick

[katy]

The oxidation of the copper prevents the solder from bonding to the copper, if the flux that you're using removes the oxidation, you're good. Most fluxes only prevent the base metal from oxidizing due to the heat. The copper should be clean before soldering, either chemically, sanding, or scraping.

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