What is the code requirement for combining two different voltages in the same conduit? I have a three phase 480volt compressor unit and a 120volt receptacle to feed at the same location, and I only have one conduit for a homerun. All the conductors in the conduit have the same insulation-THHN. Is this a safe and legal way to install these circuits?

Hi,& Welcome!
Yes, I don't like it much, but try NEC 300-3 (c).
Legal, yes.
Safe, probably.
Sound engineering, ??


[This message has been edited by electure (edited 07-11-2001).]

Well thank you for that information. I guess it's just a question of money. Does the contractor pay for two 100ft. runs of EMT or just use one. Me myself I have never combined two different voltages in the same conduit or box for that matter. This is a job that I have just walked on to on Monday.So all the pipework was already done. But thanks again for that code article I will look it up now for future reference.