One Way To Splice a Power Cable

[rgsparber]

It's been a while since I looked, but I thought NASA required the splice be wrapped with bus-wire before soldering for stability. Regardless of NASA, if these cables handle mains power or decent amount of current, they should be mechanically reinforced before soldering. Crimp is the preferred method, but wrapping with solid wire is acceptable. I have seen, on more than one occasion, over-current melting the solder joint before the circuit breaker could trip. Should the live end of the wire detach and touch something, it can be hazardous.
While I am at it, tinning wire before crimping, or using in screw clamp connectors is a bad idea, since the solder relaxes and migrates overtime and the joint becomes loose (solder does not spring back and push against the screw, leading to loosening over time).

However, on low voltage and low current circuits, I do the same thing.

I now see that I caused some confusion when I talked about "power cables". I have changed the title to "extension cords".

I'm not sure what you mean by "low voltage" and "low current" but my intent was to splice extension cords used in 120V circuits which carry under 10 amps.

I completely agree about the dangers of tinning wires before crimping or using screw clamps.

I had not thought about faults causing the solder to melt before the breaker trips. It does surprise me given the large resistance of the extension cord and the low resistance of the splice. Wouldn't the extension cord start to burn first?

I have never been able to apply heat to a Western Union splice and have it detach unless it is also under a lot of tension. In this case, the wire usually breaks next to the splice. Now, if it was a simple lap joint, it is not to be trusted.

Rick