Industrial applications

[loucan40]

I had heard that the minimum conduit size for industrial equipment is 3/4 inch using emt. I cannot find anywhere in the code book to substantiate this. If anyone knows the answer please reply. Please let me know what section of the code book this is in if true.

 

[bphgravity]

Re: Industrial applications

Article 358.20 states the smallest allowed EMT is trade size 1/2. I dont not know of any exceptions to this that would require a larger minimum size.

As a matter of fact, Article 430.145(B) allows trade size 3/8 for this application only, which would be readily found in an industrial location.

FYI: There is a proposal for a new Article for the 2005 NEC, "409 - Industrial Control Panels."

Proposal # 11-5 Code Section: New Article 409 oProposal 11-5 recommending a new Article 409 "Industrial Control Panels" was accepted at the ROP meeting. This proposal is intended to provide guidelines for manufacturers, installers, and inspectors of specialty control panels. Subsequent to the ROP meeting the ballot vote was 9 Affirmative and 5 Negative.

This realy has nothing to do with the question, but I thought I would pass it on anyway.

 

[tom baker]

Re: Industrial applications

You won't find it in the NEC as it is not there. 3/4" is a common minimum size in specs, which are used because of some special application.

 

[dereckbc]

Re: Industrial applications

Third vote. No such requirement in the NEC for 3/4 minimum EMT. Some company policies require 3/4 inch minimum, but it is not derived from the NEC.

 

[roger]

Re: Industrial applications

I'll jump in here too. The 3/4" minimum is a common engineering specification, but as stated by the others, it is not a code issue unless the "fill calculations" come in to play.

I do have a problem in some respect to this being specked when 1/2" inch will suffice. This is added expense to the customer not to mention wasting natural resources.

One more observation, in most "industrial" applications RMC or IMC is the norm.

Roger

 

[don_resqcapt19]

Re: Industrial applications

If you bend 1/2" rigid or IMC on a mechanical bender in the 1/2" shoe, it is almost impossible to pull the wire. I agree that there are many cases where 1/2" is fine for the application, but if possible you should bend it on the 3/4" shoe.
Don

 

[roger]

Re: Industrial applications

Don,

I agree that there are many cases where 1/2" is fine for the application, but if possible you should bend it on the 3/4" shoe.

no argument there.

Roger