Aluminum EMT

Status
Not open for further replies.
J

jmellc

Senior Member
Location
Durham, NC
Occupation
Facility Maintenance Tech. Licensed Electrician
i saw a journal ad this week for aluminum EMT. Has anyone here seen or used any? I called a supply house & they haven’t seen it yet.
 
We have been using it for many years for our outdoor CT metering applications. Just started using PVC about 10 years ago where the chance for damage is minimal
 
I've used it once. I don't really see much of an advantage unless it were outdoors. Yes it's lighter and easier to cut but the advantages just about end there.
 
Hv&Lv said:
We have been using it for many years for our outdoor CT metering applications. Just started using PVC about 10 years ago where the chance for damage is minimal
Click to expand...

Is what you been using Aluminum EMT or Aluminum RMC? Aluminum RMC is and has been somewhat common over the years.

Never seen aluminum EMT, though it apparently exists. For most applications with normal to moderate physical abuse potential I wouldn't think it would be that great of a choice for smaller sizes like 1/2 through 1 inch, maybe still not so great of choice for anything under 2 inch.
 
I've used aluminum RMC at times for 40 years. Most of it underground. I had occasion to a few weeks ago to do a repair on a run that was in the ground for probably 25 years. It was like new.

Aluminum RMC is a good alternative where PVC can be damaged or will look like a sagging rubber hose along the outside of a building. It's also a good alternative to EMT outside where it will corrode (as will RGS over time).

Never heard of aluminum EMT.

-Hal
 
hbiss said:
I've used aluminum RMC at times for 40 years. Most of it underground. I had occasion to a few weeks ago to do a repair on a run that was in the ground for probably 25 years. It was like new.

Aluminum RMC is a good alternative where PVC can be damaged or will look like a sagging rubber hose along the outside of a building. It's also a good alternative to EMT outside where it will corrode (as will RGS over time).

Never heard of aluminum EMT.

-Hal
Click to expand...

Aluminum is not permitted in direct contact with the earth or concrete without supplemental protection. In my area if you directly buried AL RMC it all you would be left with is white power within a year.
 
curt swartz said:
Aluminum is not permitted in direct contact with the earth or concrete without supplemental protection. In my area if you directly buried AL RMC it all you would be left with is white power within a year.
Click to expand...

I have seen it turn to toothpaste when only run under a concrete. I don't remember the part about direct contact with the earth being in the Code back 40 years ago. I think all it said was install it where judged suitable for the environment. Obviously the earth chemistry here isn't alkaline like where you are.

Still, I wouldn't use it like that today, can't. I made that repair mentioned above with RGS.

-Hal
 
I didn't know there was such a thing as Al EMT. But since it is directly referenced in the code, it probably exists.

Part II. Installation
358.10 Uses Permitted.
*
(B) Corrosive Environments.
*
(2) Supplementary Protection of Aluminum EMT. Aluminum
EMT shall be provided with approved supplementary corrosion
protection where encased in concrete or in direct contact with
the earth.
Click to expand...

The supplementary protection requirement is new to the 2017 code.
 
I would also add to (2) "where in direct contact with damp or wet concrete". This would be on something like a poured concrete wall. If it gets wet the back of the conduit is going to turn to toothpaste. Would be an appropriate place to use backstraps.

-Hal
 
Status
Not open for further replies.
Top