Aluminum Conductors

[Frank DuVal]

or from the pole transformer to my home.

I have not seen our power company use copper for pole to house in ... let's say 70 years! I've never seen copper triplex. It may be a thing, but I have never seen it installed.

 

[don_resqcapt19]

We see very little aluminum installed by the electrical contractors around here....it is very rare to see a project design that permits the use of aluminum conductors in this area.

 

[BarryO]

I've never seen copper triplex. It may be a thing, but I have never seen it installed.

Only seen it in coastal areas.

 

[tom baker]

Don have there been any studies on fires where EMT is only allowed vs other locations where NM can be used?

 

[electrofelon]

If I was into maximum conductor reliability, I would use compression terminals at the terminations. If I had to choose one, I would choose aluminum conductors with compression connectors over copper with mechanical lugs

 

[SceneryDriver]

230119-1557 EST

...or from the pole transformer to my home...

How do you propose to dictate what the PoCo does and how they connect your home on the Utility side?

From a practical side, overhead copper conductors would be prohibitively heavy.

Hundreds of thousands of miles of overhead aluminum conductors are installed in this country; we don't see everything burning down every day.



ScenreryDriver

 

[don_resqcapt19]

Don have there been any studies on fires where EMT is only allowed vs other locations where NM can be used?

There was a published comment by the chief electrical inspector for the City of Chicago that said the number of fires said to be of electrical origin in the city is 1/4 of the national average. This comment was in support of the code rule in 210.12(A)(5) back when that was being proposed for the code.

There are probably a lot of reasons for that, but I expect the EMT requirement is one of those reasons.

 

[letgomywago]

There was a published comment by the chief electrical inspector for the City of Chicago that said the number of fires said to be of electrical origin in the city is 1/4 of the national average. This comment was in support of the code rule in 210.12(A)(5) back when that was being proposed for the code.

There are probably a lot of reasons for that, but I expect the EMT requirement is one of those reasons.

I wonder if part of this is it keeps people from diy anything beyond device change out. It's more daunting to move a conduit and install proper junction boxes for it than just a bit of romex and a plastic box for a homeowner or handy hack. Not saying I'd want to see this be a requirement for here but it would be something any safety requirement would need to control for in a study. As much as I dislike afci it does add enough barrier to entry for electrical that people are forced to not mix nuetrals or exposed conductor in a burned up box that helps. Newer afci doesn't have gfpe though so that little benefit may be going away soon.

 

[retirede]

There was a published comment by the chief electrical inspector for the City of Chicago that said the number of fires said to be of electrical origin in the city is 1/4 of the national average. This comment was in support of the code rule in 210.12(A)(5) back when that was being proposed for the code.

There are probably a lot of reasons for that, but I expect the EMT requirement is one of those reasons.

My totally uneducated guess is that this is probably because the EMT requirement minimizes the amount of DIY, handyman, and other hack work, as opposed to the physical properties of the wiring method.

 

[don_resqcapt19]

My totally uneducated guess is that this is probably because the EMT requirement minimizes the amount of DIY, handyman, and other hack work, as opposed to the physical properties of the wiring method.

I have seen plenty of hack work installed by professionals. The EMT is not all of it, but it is a part of it.
Also the home centers there all sell EMT and the associated fittings. Not that difficult to install for small DIY projects.

 

[retirede]

I have seen plenty of hack work installed by professionals. The EMT is not all of it, but it is a part of it.
Also the home centers there all sell EMT and the associated fittings. Not that difficult to install for small DIY projects.

All fair points.

 

[BarryO]

There was a published comment by the chief electrical inspector for the City of Chicago that said the number of fires said to be of electrical origin in the city is 1/4 of the national average. This comment was in support of the code rule in 210.12(A)(5) back when that was being proposed for the code.

There are probably a lot of reasons for that, but I expect the EMT requirement is one of those reasons.

I had always heard that it was a result of community PTSD after the 1871 fire. Although it's so entrenched now and I imagine is supported by the business establishment.

Same as here in Oregon where self-service gas is banned in half the counties in the State, and fire danger is often used as a rationale. I dunno, I never hear about the nationwide scourge of gas station fires.

 

[junkhound]

Back in 60's thru 1980's did a lot of Minuteman and Peacekeeper missile silo wiring. Only written requirement was compliance with NEC as a minimum. However, never saw aluminum used, an unwritten rule. All engineering designs went thru critical design reviews, everything in rigid conduit due to nuclear shock requirements. No one ever even suggested using aluminum to the best of my recollection. Another IIRC, any termination over 12 AWG was hydraulic crimp lug.

Obviously on aircraft aluminum on larger conductors aluminum is the obvious choice for the weight, but terminations always copalum or similar high pressure crimps.

As far as discussion with the base regarding their copper only policy, can we ask which base? Some of the system reliability needs are such that even the hint of a power connection that can degrade with time (aluminum cold flow?) is anathema to system reliability folks.

My most recent military base work was Shriver AFB outside Col. Springs, saw NO aluminum wire there, GMD building very concerned with reliability, full itme UPS for entire buildings. Copper and alum data shows higher reliability for copper. Anytime a circuit breaker tripped, there was a full review of WHY it tripped, sometimes involving more than 4 or 5 meetings and reviews. Even though electricians working on site had top secret clearances, still corp of eng folks had worries about posibility inferior workmanship on an aluminum termination.

 

[drcampbell]

... Hundreds of thousands of miles of overhead aluminum conductors are installed in this country; we don't see everything burning down every day.

True, but it does require maintenance.

 

[drcampbell]

My totally uneducated guess is that this is probably because the EMT requirement minimizes the amount of DIY, handyman, and other hack work, as opposed to the physical properties of the wiring method.

When I lived in Chicagoland, there didn't seem to be any hesitation among DIYers to do electrical work. It was all EMT, it was what we all grew up with and were familiar with, we often didn't know that other wiring methods even existed, and it wasn't daunting at all.

Which is not to say that EMT prevented hack work. The house I grew up in had the detached garage electrified by a tapping one traveler of a stairway light (and underground EMT? Never had cause to look) and a neighbor's house was done entirely with orange and purple wire. Didn't see them go in, so I have no idea whether it was a DIYer or a "professional".

Chicago Style (EMT) was so familiar that when I moved away, I was reluctant to specify NM. I still recommend it for garages with exposed studs.

 

[Strathead]

I had always heard that it was a result of community PTSD after the 1871 fire. Although it's so entrenched now and I imagine is supported by the business establishment.

Same as here in Oregon where self-service gas is banned in half the counties in the State, and fire danger is often used as a rationale. I dunno, I never hear about the nationwide scourge of gas station fires.

I am of the belief it is mostly due to strong unions. San Francisco used to have the same requirements, but that change in the late 1900's.

 

[Strathead]

Charlie, I would try a different approach. I would ask for their concerns or reasons, which you could then debate. My biggest argument is that there are 10's if not hundreds of miles of aluminum between their building and the power generation plant, do they really think the last 100 feet is going to make the difference?

 

[kwired]

I am of the belief it is mostly due to strong unions. San Francisco used to have the same requirements, but that change in the late 1900's.

I'm sure it probably was the unions, but they likely used the fire to help push their agenda.

 

[kwired]

I have seen plenty of hack work installed by professionals. The EMT is not all of it, but it is a part of it.
Also the home centers there all sell EMT and the associated fittings. Not that difficult to install for small DIY projects.

I've seen plenty of hack work involving EMT myself. 1/2" flex connectors on 3/4 EMT. I suppose most times was used because they were running 3/4 but only had 1/2 KO in the box. Might sometimes see this with larger sizes as well but seen the 1/2" connector and 3/4 raceway the most. Also seen 90 degree flex connectors used with EMT, worse yet they even get concealed in walls that way. Seen many times they ran EMT all over the place then pulled NM cable through it. Even if they did a decent job with the raceway install - why make it harder on yourself by pulling NM cable through it?

 

[ggunn]

Back in 60's thru 1980's did a lot of Minuteman and Peacekeeper missile silo wiring. Only written requirement was compliance with NEC as a minimum. However, never saw aluminum used, an unwritten rule. All engineering designs went thru critical design reviews, everything in rigid conduit due to nuclear shock requirements. No one ever even suggested using aluminum to the best of my recollection. Another IIRC, any termination over 12 AWG was hydraulic crimp lug.

Obviously on aircraft aluminum on larger conductors aluminum is the obvious choice for the weight, but terminations always copalum or similar high pressure crimps.

As far as discussion with the base regarding their copper only policy, can we ask which base? Some of the system reliability needs are such that even the hint of a power connection that can degrade with time (aluminum cold flow?) is anathema to system reliability folks.

My most recent military base work was Shriver AFB outside Col. Springs, saw NO aluminum wire there, GMD building very concerned with reliability, full itme UPS for entire buildings. Copper and alum data shows higher reliability for copper. Anytime a circuit breaker tripped, there was a full review of WHY it tripped, sometimes involving more than 4 or 5 meetings and reviews. Even though electricians working on site had top secret clearances, still corp of eng folks had worries about posibility inferior workmanship on an aluminum termination.

I have designed a couple of PV systems for military facilities. The "no aluminum conductors" clause was in every contract.