Splicing Aluminum Power and Control Wiring in an Industrial Plant 1

[bdn2004]

We are replacing some Motor Control Centers at a plant that was wired with aluminum wiring for both the power and control. Some of the wires will be too short by 2 or 3 feet. They range in size from #12 to #350. Re-wiring the entire circuit with copper conductors is the last option.

We have considered butt splicing. Someone else suggested soldering, which I had not heard of. Any suggestions on the best way to make such a splice, or testimony to the reliability of a butt splice?

 

[davidbeach]

A properly applied compression splice listed for both aluminum and copper would probably be your second best solution. No splice at all, even at the cost of entirely new conductors, is vastly superior.

 

[dpc]

I would NOT recommend soldering. A listed compression splice, properly installed should work OK. I'd buy the special tool for crimping the splices as well. Takes out a lot of guesswork.

 

[rcw retired EE]

Based on experience - you should plan on replacing the #12 and smaller aluminum wires. At a now out-of-business aluminum company, we used all aluminum wire for one plant, including, #14 and #12 awg control wire.

After a few years, almost any bending of the wire caused the conductor to break inside the insulation. During troubleshooting, we would lift a wire off a terminal strip to check for control voltage at the terminal and then replace the wire. That little bending action of lifting and replacing the wire would break the conductor enough to stop the circuit. Drove us crazy. Troubleshooting efforts created more problems until we did a 100% replacement with copper control wiring.

IMHO - Compression splices are the best way to go for the power cables.

 

[dpc]

rcwilson,

Was this stranded wiring?

 

[rcw retired EE]

I think it was solid wire in the control wiring sizes. But that was 25 years ago so my memory may be failing.

BTW - the plant was built in the late '50's and used aluminum as much as possible. In the mid '60's the company switched to using aluminum wire only in #6 awg and larger and later went to #1/0 awg and larger to avoid termination problems.

 

[stevenal]

I don't think you'll find too many compression fittings listed for use with the #12 aluminum. There is one for pigtailing copper, but tooling and the required training will be expensive and hard to justify for a few control centers.

Mechanical connectors are available for the #12. #10 and up have more compression choices.

 

[waross]

I agree with rcwilson. Compression splice the larger cables and replace the smaller wires.
respectfuly