Transformer piping

[rayshuman]

Is there any place in the code that says you can or cannot hard pipe all the way to the transformer, or to use some type of flexible conduit for the last few feet. I cannot find anything specific in the NEC.

 

[templdl]

Re: Transformer piping

Best not to pipe directly to the xfmr enclosure as there it a good possibility that to do so would transmit noise generated by the transformer to the walls and other surfaces to which conduit is fastened.
As long as you use listed and approved methods of transitioning from EMT to flex there isn't an issue.

 

[mdshunk]

Re: Transformer piping

The first time you have to do an emergency service call to change out a transformer that was hard piped, you'll always install yours with the last few feet as flex.

 

[tom baker]

Re: Transformer piping

Any wiring method can be used for any application in accordance with its uses allowed and not allowed.
Flex is fine, but it still needs to be supported.

 

[benaround]

Re: Transformer piping

rayshuman,

Hard piping to a transfomer is not a code violation. Most are connected by flex. IMO a short run of a large conductor will transmit vibrations.

 

[peter d]

Re: Transformer piping

Originally posted by rayshuman:
I cannot find anything specific in the NEC.

This is a good opportunity to point out the NEC is highly non-specific in this regard, and for good reason. If it had a rule or permission for every situation we encountered, it would look something like the old World Book Encylcopedia.

Bottom line, if the NEC doesn't say you can't, then you can. This makes the NEC a permissive document.

Now, as far as your question goes, I don't do large commercial work but each and every transformer I have ever seen was connected with flexible metal conduit.