Joining allum nm to copper nm

s far as I know they are the ONLY approved method, IF they are the correct "crimp sleeves" not the ones you stick the wires in and then pinch with a "pliers type" tool. Expansion and contraction make wire nuts impractical.
 
When joining copper and aluminum conductors together the key is to keep them from contacting each other. Any device that allows them to touch each other is not a good idea and will result in a failed connection.
 
"Crimps" are NOT an approved method. The ONLY approved method is an APPROVED method, such as a CopAlum splice or a specific CO/AL splice.
 
Thank You one N all . I believe during the Nam war a lot of Allum. was used in Homes. Also copper covered Allum. It stinks to relocate a big sub panel with old Allum
and New copper . Long hard day by My self.
 
The companies which make the Cu-Al "splices" call them "crimps" and use a "crimping tool" to secure them. Don't the aluminum bus bars have circuit breakers snapped on to them with the wire attaching to the breaker, not the bus bar?
 
The crimp connectors as well as the twist on connectors that are marked cu/al have a very high failure rate. Those that use a screw to hold each wire are the best for the job at hand

On a side note; the repair of aluminum is not a DIY project unless you have a desire to lose your home. I would not let a licensed electrical contractor work on my aluminum circuits unless he could show me paper work that he has been trained on the subject matter.
 
quote; OK, but either way these are very, VERY, specific "crimps" designed for the job.

Which is WHY, I specified that they have to be the "correct crimp" devices, and use the specfic crimping tool for them, neither of which is "inexpensive". Those with a screw retainer in the side, CAN loosen because of expansion and contraction, the same as panel connections which use a "screw" to anchor the aluminum. Have you NEVER seen an aluminum power wire with the insultion melted back several inches from its anchor point because it has loosened and created resistance and thus heat? I have several times.
 
hj said:
quote; OK, but either way these are very, VERY, specific "crimps" designed for the job.

Which is WHY, I specified that they have to be the "correct crimp" devices, and use the specfic crimping tool for them, neither of which is "inexpensive". Those with a screw retainer in the side, CAN loosen because of expansion and contraction, the same as panel connections which use a "screw" to anchor the aluminum. Have you NEVER seen an aluminum power wire with the insultion melted back several inches from its anchor point because it has loosened and created resistance and thus heat? I have several times.
Click to expand...



Most often - but more common is that those that are bright enough to use no-alox in the connection [speaking of larger feed wires] to stop the oxidation of aluminum, and then go back and re-torque. You can bust a nut tightening on a main AL wire and come back in a week and get an easy 3/4 turn. Then you have your neutral and ground bars that are aluminum with copper wires stuck in them. Interesting engineering. The latest GE panel I bought seems to have gone to a copper plated steel bar with a bit of "dip" in the under screw area to insure a good connection.
 
hj said:
quote; OK, but either way these are very, VERY, specific "crimps" designed for the job.

Which is WHY, I specified that they have to be the "correct crimp" devices, and use the specfic crimping tool for them, neither of which is "inexpensive". Those with a screw retainer in the side, CAN loosen because of expansion and contraction, the same as panel connections which use a "screw" to anchor the aluminum. Have you NEVER seen an aluminum power wire with the insultion melted back several inches from its anchor point because it has loosened and created resistance and thus heat? I have several times.
Click to expand...
Having worked with aluminum branch circuits for more than forty years I would consider myself somewhat versed on the subject. Over the years I have used every type of aluminum to copper conversion kit on the market and have had failures in all of them except one. The one in which I have never had a failure was with the ones with a set screw for each conductor.

ballvalve said:
You can bust a nut tightening on a main AL wire and come back in a week and get an easy 3/4 turn. Then you have your neutral and ground bars that are aluminum with copper wires stuck in them. Interesting engineering. The latest GE panel I bought seems to have gone to a copper plated steel bar with a bit of "dip" in the under screw area to insure a good connection.
Click to expand...
If one can get ¾ turn on a terminal one week after installation this says one thing, it was not properly installed the first time. In over 44 years of doing electrical installations I have yet to see an aluminum bus bar or terminal bar installed in any of the panels I have worked with. I have seen aluminum alloy but never aluminum.

hj said:
NO-ALox will do nothing to prevent expansion contraction movement or lossening.
Click to expand...
and in today’s market it does nothing for the conductor either.
 
The proper Crimps should change size with temperature as the material that they are made for.
Using the wrong crimp tool is the mistake that many make. Crimp tools are calibrated for a reason.


The set screw types and Torque wrench are safer if you do not have the proper calibrated crimp tool.
 
The only approved crimp is the Cop-alum by Tyco. You need to be trained and lease the tool from Tyco.

The Alumi-conn by King seems like a nice splice but calls for a torque screwdriver for proper application.
 
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