Question from:

Theodore P. Von Sydow
US. Department of State

My question in a nutshell: Can a conductor pass through a transformer if it is not connected to the transformer?

Can the transformer be used as a raceway for a circuit or conductor that is not directly related to the function of the transformer?

Thank you

If there is no violation of voltage class' of insulation, or type of wiring (communications, fire alarm, etc), seems ok.

This is not a good practice.
If the transformer fails, you would have to remove the conductor and disrupt it's loads in order to replace the transformer.

I agree, no foreign wires are to be passed through the transformer. I expect that there will be many who wear the AHJ hat that will agree. It is also common knowledge that all conductors are not to be passed through an area that originates in the top section -- the label in the transformer enclosure will cleary identify this and other restrictions.

I also agree, not a good practice. I think the original questions infers that the poster wants to know if it is a code violation. I don't find a violation.