Using CU switches with Al Wiring ?


Old 08-18-06, 07:28 PM
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Using CU switches with Al Wiring ?

What is the major differences between outlets & switches designed for Al wiring vs. ones designed for CU? As long as you really tighten the screws holding the Al wire onto the terminal and use No Ox, shouldn't the switch / outlet designed for CU perform just fine with Al wire?
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Old 08-18-06, 09:38 PM
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First, it is a code violation, so why would you even consider doing this, just because you think it is ok?

Devices rated COALR have terminals and screws made of a material which is compatible with direct contact with aluminum. Other devices may have plain brass or some other material. Despite using the NoAlOx, you have dissimilar metals in contact with each other, which may react , causing the corrosion which is the fire-starter.
Old 08-18-06, 10:31 PM
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secondly, If you don't know the proper terms or items you should not comment.

PS: Bluesteel. let me know your Area/region of work. So I know where NOT to rest my head.

And to think I was at first skeptical of a "Salesman".
Old 08-18-06, 10:39 PM
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Most electrical devices used on 15 and 20 AMP electrical circuits, which will be the bulk of the devices in question here, have brass terminations. Brass and aluminum mixed sets up a reaction that will cause the aluminum to deteriorate eventually.

CO/ALR rated devices have terminations plated with indium or a similar material that prevents direct contact of the brass and aluminum. Additionally, there is a slightly abrasive area on the contact that will allow it to break through oxide on an improperly prepared wire and make good (or at least better) contact with the wire.

The fact that devices rated for use on aluminum wire are different than standard devices ought to be a clue that using CU only rated devices on aluminum might cause problems. Why would you even think that tightening the screws a bit more would cure the problem after all the fuss about aluminum wire - which you do seem to be aware of.

FWIW, good practice dictates coating the wire with an anti-oxident, then using a steel brush to remove the oxide from the wire. Then, wipe the wire (you won't get all the anti-oxident off) and reapply a bit more. After all this, you use a torque screwdriver to tighten the screws to the manufacturer's specs. Figure on being able to do 2 or 3 switches/receptacles an hour when you get good at it.

With all the above, the devices will need periodic inspection to check screw tightness (at least annually) on heavily used circuits, and I don't consider these devices to be a permanant fix. Installing copper is a permanant fix.

Last edited by itsunclebill; 08-18-06 at 10:53 PM.
Old 08-18-06, 11:01 PM
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MR/MS/Miss Blue steel. I would like to apoligize for my "knee jerk reaction" .
My understanding of the comment was skewed.
Thanks Uncle Bill, for letting me see this.
Old 08-18-06, 11:04 PM
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Note: If you are in Canada and my memory cells are working correctly you are not allowed to use CO/ALR receptacles and switches you must pigtail copper to the aluminum wires and only by a special crimping method called the COALM crimp then use cu only switches and receptacles. This takes special tools and a certified electricain trained in its application.

Maybe Joed can fill in the blanks.....


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