EMT

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ceb

ceb

Senior Member
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raeford,nc
emt ran exposed on outside of building foundation.Is this still allowed? I know that 358.10a and 358.10c address this but I have heard that is was not allowed due to water tightness of the compression couplings and adapters. What is the correct answer? commercial application.
 
Re: EMT

Yes it is permitted. The situation you are talking about is the UL listing on Raintight fittings, and Bridgeport has 'new' listed fittings in the 1/2, 3/4, and 1 inch size available.
As far as Jim's mentioning of the EMT rusting, that has occurred and each situation is different. You should be aware if this is a problem where you work.

Pierre
 
Re: EMT

Check for any local amendments too. ex. Palm Beach county wants an insulated gnd wire run with outside EMT - can't using the pipe as sole gnd.
 
Re: EMT

I can't seem to find where the NEC wont allow EMT in soil. But I remember being told that it's not allowed? I know that 358.10(B) say's:
where protected by corrosion protection and judged suitable for the condition.
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But does this mean that it has to have rubber coating? to go in soil? Every time I had to dig up ENT that has been buried the pipe almost falls apart in your hands.
 
Re: EMT

From the UL Guide Information for EMT.
Galvanized steel electrical metallic tubing installed in concrete on grade or above generally requires no supplementary corrosion protection. Galvanized steel electrical metallic tubing in concrete slab below grade level may require supplementary corrosion protection.

In general, galvanized steel electrical metallic tubing in contact with soil requires supplementary corrosion protection. Where galvanized steel electrical metallic tubing without supplementary corrosion protection extends directly from concrete encasement to soil burial, severe corrosive effects are likely to occur on the metal in contact with the soil.

Aluminum electrical metallic tubing used in concrete or in contact with soil requires supplementary corrosion protection.
Click to expand...
Don
 
Re: EMT

I believe Mike Holt his self got started in being a code guru after running into a problem on Federal Highway in Fort Lauderdale. As I heard the story the city or County tried to ban EMT outside completely. The case which Mike won left it banned east of Federal Highway. Then it slid back to East Coast Railroads tracks... Now I think it may have slid back further. But, I have stopped using EMT period.

I wonder if anyone can confirm the story I just posted? It is the explaination I have always heard from folks around here. Long before there was ever a Mike Holt forum. LOL
 
Re: EMT

I want to make a comment about using the EMT as the sole grounding connection back to the source.
And for that matter any metal conduit, period.
I have had the experience of checking the continuity of conduit being the only source of carrying the grounding connection.
What will happen is this. At the coupling, due to corrosion, you will lose your continuity of your ground. Where I worked we did use the conduit as the only source of grounding for many years. We have changed our policy, and now we always carry a separate ground wire in the conduit. I feel that this is the best method of assuring that we always have a good ground connection, back to the source.
 
Re: EMT

Originally posted by friebel:
What will happen is this. At the coupling, due to corrosion, you will lose your continuity of your ground.
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Friebel
I believe Joe T. has stated a change is in the works for 2005 that a grounding conductor will be required for outdoor EMT installations.

Maybe someone can confirm that.

That said, it is important to make clear that currently 250.118 allows the use of RMC, IMC, EMT and many other metal raceways as a grounding conductor.

However I have not seen a job specification in a long time that did not require a copper grounding conductor in any raceway. :)
 
Re: EMT

We still have a ways to go in order to know what is in the 2005 NEC. We have turned in our votes the first time. The NFPA has re-circulated all the comments and voting status with a chance to change you votes. The TCC has to go through all the panel actions and may hold some of the actions for the 2008 cycle. We will not know how the votes came out until the ROC is printed and distributed.

After that, we have the NFPA Annual Meeting in Salt Lake City where the 2005 NEC will be adopted in May. Some items may be sent back to the technical committee (code making panel) for review and possible change. There is also the appeals process to the Standards Council and the NFPA Board of Directors.

With all that said, we really do not know for sure what changes will be made. :D
 
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