NEC Compliant EMT

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Billwalton

Member
Location
Portland, OR, USA
I would like to purchase offshore manufactured EMT tubing. The tubing would not be U/L approved because it is pre-galvanized.
U/L requires about 25 microns of zinc to stand up to their copper sulphate (Preece) Test. As far as I can tell NEC has no requirement on corrosion resistance. Pre-gal is used in many countries and creates less health and environmental issues. Can anyone tell me what I need to do to establish if we would be NEC compliant?

Thanks!
BW
 
Dennis Alwon

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
If there is no third party listing then I don't believe there is anything you can do. Btw, emt is legal underground in some cases so how would you deal with that?

358.10 Uses Permitted.
(A) Exposed and Concealed. The use of EMT shall be permitted
for both exposed and concealed work for the following:
(1) In concrete, in direct contact with the earth or in areas
subject to severe corrosive influences where installed in
accordance with 358.10(B)
(2) In dry, damp, and wet locations
(3) In any hazardous (classified) location as permitted by
other articles in this Code
Click to expand...
 
rbalex

rbalex

Moderator
Staff member
Location
Mission Viejo, CA
Occupation
Professional Electrical Engineer
There is a general requirement for corrosion protection for all raceways in Section 300.6 and a specific requirement that EMT be listed in Section 358.6 and have corrosion protection in Section 358.10(B). It would seem the product you would like to use is not NEC compliant.
 
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petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
Billwalton said:
I would like to purchase offshore manufactured EMT tubing. The tubing would not be U/L approved because it is pre-galvanized.
U/L requires about 25 microns of zinc to stand up to their copper sulphate (Preece) Test. As far as I can tell NEC has no requirement on corrosion resistance. Pre-gal is used in many countries and creates less health and environmental issues. Can anyone tell me what I need to do to establish if we would be NEC compliant?

Thanks!
BW
Click to expand...

I don't know what you mean by "pre-galvanized".

In any case as others have mentioned there is a requirement that EMT be listed.

I think one of the requirements for listing is that the inside of the EMT has to have a polymer coating. I think they spray it with a varnish of some sort.

It really is not EMT if it is not listed, but there is also no requirement that it be made in the USA to be listed.
 
kwired

kwired

Electron manager
Location
NE Nebraska
Dennis Alwon said:
He is an electrical supplier... Not sure what his intention are with that.
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I didn't read profile. Need to be careful with that though. Sure you might be competitive with price -but if/when clients and/or inspectors find out, you will have unhappy campers. Might be enough they don't trust you at all and they stop purchasing from you period.
 
kwired

kwired

Electron manager
Location
NE Nebraska
petersonra said:
Is this any worse than the unlisted Flex that is commonly sold?
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Good point. I know I can get both listed and non listed LT flex from one of my suppliers. 1/2 x 8 foot ground rods are supposed to be listed. Found out some time ago that one supplier's rods weren't listed. Nobody really knew or really cared - until I suppose some inspector caught on. Now they only sell listed rods AFAIK. Price went up some - bet performance of rods changed very little.
 
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Billwalton

Member
Location
Portland, OR, USA
kwired said:
I didn't read profile. Need to be careful with that though. Sure you might be competitive with price -but if/when clients and/or inspectors find out, you will have unhappy campers. Might be enough they don't trust you at all and they stop purchasing from you period.
Click to expand...


I am not going to do anything that would make an inspector or customer unhappy. I'm wondering if I get third party verification other than U/L if that would satisfy NEC.
 
kwired

kwired

Electron manager
Location
NE Nebraska
Billwalton said:
I am not going to do anything that would make an inspector or customer unhappy. I'm wondering if I get third party verification other than U/L if that would satisfy NEC.
Click to expand...
Whatever you do don't pass it on as regular EMT. Once you are found out doing that it probably bites you back.

That said, if customers know it isn't listed, you probably don't sell much of it, unless you have a certain sector of clients that don't get inspected and don't care that it isn't listed.
 
S

sameguy

Senior Member
Location
New York
Occupation
Master Elec./JW retired
I had to replace all the galvrig and ss boxes in some off shore built skids that a manuf. thought were saving money for their cogen power plant in a box concept, rhymes with Thomas Edison, (x.x.), due to no UL and customers in the U.S. refusing when the units arrived for set up. Would have been traveling all over the U.S. but the Co. I worked for got too greedy and lost the contract on the day I was to leave.
I would sell it with full disclosure, if you think it will sell.
 
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