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More aluminum wiring mistakes


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When I get a home with aluminum wiring, I always open up at least two receptacles and I've never been disappointed - they are always wrong. Here's yesterday's pig-tailing done with 3M connectors that are listed for "copper only." (This is the same home as the spliced GEC) Done by a licensed electrician. The metal boxes were still using the aluminum ground wire but I believe that is OK, can anyone verify for me? TIA

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I may be pushing it by actually pulling the receptacle out of the box, but I'll take the heat as it is the only way to determine if the repairs are proper or not. That particular wire nut literally fell off as the electrician had put so much anti-oxidant paste on it didn't actually twist on, was just pushed on. I don't usually remove the connectors. We each do what we feel comfortable with doing.

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But can the aluminum ground still be used to the metal boxes? A ground doesn't normally carry current so I wouldn't think it needs to be pig-tailed but I really have never seen a definitive answer. Anyone?

The equipment grounding conductor should terminate on the green screw on the receptacle. If it's listed as CO/ALR, then the aluminum can run directly to it. If not, then an Alumiconn splice to copper wire would be one other way to do it.

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And another question to everyone is - do you pull receptacles out to look with aluminum, or with anything actually, or just remove the cover and try to peek around? Just curious now what everyone else does.

I can usually see what I need to see by simply removing the coverplate.

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If it's got aluminum wiring it was probably built mid-60's to mid-70's. I thought a lot of homes back then had the EGC connected to to metal boxes when they were used.

I remember helping my father rewire one of the old homes he bought to flip back in the '60's. A local electrician, a friend of my father's, came over and taught him how to do it. I was sitting there watching. He taught him to put a loop in the EGC and loop it around a little screw at the back corner of the box, tighten the screw and then pull the end out of the box where it could be connected to the receptacle. Whenever I've wired a receptacle with a metal box since, I've done it exactly that way. I'd always thought it had something to do with ensuring any fault current that energizes the metal box finds its way back to earth. It never occurred to me that it might not be right and proper.

ONE TEAM - ONE FIGHT!!!

Mike

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If it's got aluminum wiring it was probably built mid-60's to mid-70's. I thought a lot of homes back then had the EGC connected to to metal boxes when they were used.

I remember helping my father rewire one of the old homes he bought to flip back in the '60's. A local electrician, a friend of my father's, came over and taught him how to do it. I was sitting there watching. He taught him to put a loop in the EGC and loop it around a little screw at the back corner of the box, tighten the screw and then pull the end out of the box where it could be connected to the receptacle. Whenever I've wired a receptacle with a metal box since, I've done it exactly that way. I'd always thought it had something to do with ensuring any fault current that energizes the metal box finds its way back to earth. It never occurred to me that it might not be right and proper.

ONE TEAM - ONE FIGHT!!!

Mike

I believe what you describe is the proper way to deal with the EGC at the end of a run, around the screw and then to the receptacle. If another cable is leaving the box for another destination, then you join the 2 wires and a short jumper with a wire nut. But the wire to the box is always uncut with a long end, correct.

I sometimes will pull a cover and a receptacle if I suspect Al foul play.

I have run into opposition over what an acceptable nut for Al should be, depending on the location and the authority. So now I recommend 'maintenance of all fixtures and receptacles by a qualified and knowledgeable electrician', or something to that effect.

The rule of thumb that I use is to have all connections checked every 10 years. If that is a hardship, replace it all with copper and be done with it.

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A conductor should never loop around a screw in such a manner that the wire crosses over itself. If what you are talking about is placing a bend in the wire in such a manner that it resembles the letter omega then it is possible to go through the screw in the box or on the receptacle, though it isn't making things any easier for anyone. What's wrong with running a wire from the box and pigtailing the other equipment grounds to it?

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Makes sense to not loop the wire over itself. As to using the CO/ALR rated receptacles, I ran across this statement - what is everyone's thoughts?

"Also some incorrectly believe that repairing older pre-1970s aluminum can be done by replacing electrical devices (switches, outlets, etc.) with ones that are rated for use with aluminum wire (CO/ALR rated devices). The problem is that these modern devices are tested and listed using modern AA-8000 series alumimum wire, which is very different than older pre-1970s aluminum wire which expands and contracts much more, and is more susceptible to creep. So the CPSC considers using CO/ALR devices for older aluminum wiring only an emergency repair." Wikipedia

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Makes sense to not loop the wire over itself. As to using the CO/ALR rated receptacles, I ran across this statement - what is everyone's thoughts?

"Also some incorrectly believe that repairing older pre-1970s aluminum can be done by replacing electrical devices (switches, outlets, etc.) with ones that are rated for use with aluminum wire (CO/ALR rated devices). The problem is that these modern devices are tested and listed using modern AA-8000 series alumimum wire, which is very different than older pre-1970s aluminum wire which expands and contracts much more, and is more susceptible to creep. So the CPSC considers using CO/ALR devices for older aluminum wiring only an emergency repair." Wikipedia

I'd want to see documentation that backs up the claim that CO/ALR devices are not considered acceptable for use with pre AA-8000 wire.

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Jim- This is what is in the CPSC PDF that anyone can download - AluminumWiringFixes.pdf -

"However, CO/ALR wiring devices have failed in laboratory tests when connected to aluminum wire typical of that installed in existing homes. The test conditions simulated actual use conditions; no ?overstress? type of testing was used. Further, CO/ALR connectors are not available for all parts of the wiring system (e.g., for the permanently wired appliances and ceiling mounted light fixtures). In the opinion of CPSC staff, CO/ALR devices must be considered, at best, an incomplete repair.

Recommendations on Temporary Repairs

AL/CU twist-on connector pigtails or CO/ALR devices may be used as an emergency, temporary repair for a failed aluminum termination."

Honestly, I don't know if the receptacles and switches will fail or not, and I agree that this is the stuff produced by government. I'm not a barrister, but my point is - from a liability stand point, are we smart for telling people that using CO/ALR rated components is OK when the government is saying it's not?

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Honestly, I don't know if the receptacles and switches will fail or not, and I agree that this is the stuff produced by government. I'm not a barrister, but my point is - from a liability stand point, are we smart for telling people that using CO/ALR rated components is OK when the government is saying it's not?

Electrical components are tested and listed by "Nationally Recognized Testing Laboratories" (NRTLs). The most prominent NRTL is UL. NRTLs do not arbitrarily choose the manner in which components are tested. They are tested to published standards. For receptacles, the standard is ANSI/UL 498, and for snap switches it is ANSI/UL 20.

CPSC is not a nationally recognized testing laboratory. The engineer who provided the bulk of "their" research on aluminum is not an electrical engineer. The test protocols which were followed for whatever research led to this CPSC statement have not been published, and there is no reason to imagine they were conducted in accordance with the procedures of the published standards.

Per the NEC and the standards above, snap switches, and receptacles rated 20 amps or less, must be rated CO/ALR when directly connected by aluminum conductors. Other types of receptacles may be connected by pigtailing copper and using a suitable connector between the different materials.

If you examine a CO/ALR receptacle or switch, you will see that the underside of the terminal screw head has a saw-tooth pattern designed to bite into the conductor and increase the area of surface contact between the materials. Of course they must also be applied at their proper torque setting (20 inch pounds).

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That's a new duplex receptacle rated CO/ALR and is suitable for 10 or 12 gauge aluminum wire. The pigtails are there to increase the billable hours rather than improve the safety of the system.

The electrician is an idgit.

Serious question, are all new receptacles rated CO/ALR??? or can you actually see it on there? I didn't think the 39 cent recepts were CO/ALR, just the $2 ones.

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Serious question, are all new receptacles rated CO/ALR??? or can you actually see it on there? I didn't think the 39 cent recepts were CO/ALR, just the $2 ones.

They are a specialty item, and probably cost more the $2 these days. I doubt they sell them in home improvement centers. I've only seen them in electrical supply houses. You can see the letters on the yoke and they are also embossed on the back.

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Thanks Douglas, appreciate the feedback. If we can counter CPSC's statement with a UL rating then that is certainly worth something.

I had another home yesterday with aluminum wiring and you guys would have been proud - I only took some covers off, I didn't pull the receptacles out. See, I can learn! :)

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Serious question, are all new receptacles rated CO/ALR??? or can you actually see it on there? I didn't think the 39 cent recepts were CO/ALR, just the $2 ones.

They are a specialty item, and probably cost more the $2 these days. I doubt they sell them in home improvement centers. I've only seen them in electrical supply houses. You can see the letters on the yoke and they are also embossed on the back.

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I was pretty sure I knew the answer and that you can get them in Lowes, Menards etc. I have bought them there recently. As far as cost, .

$2.99 at Home depot

http://www.homedepot.com/Electrical-Out ... LqH-obAGso

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