Can you have a 480 volt primary transformer feed in the same pipe with 120 volt
Branch circuits.


Can you share a under ground vault with 480 volts and 120 volts arriving and leaving in separate conduits.

Neither is good practice but may allowed by the code...
Where are you planning on doing this? How many wires do you plan to
Install in a single conduit? What size are these circuits (in amps)...
Please tell us more...

Yes to both questions, assuming your using standard building wire rated 600 volts. Such as THHN/THWN or XHHW, for example.

In commercial and industrial, where both voltages are often used, it is standard practice when necessary.

Allow me to explain my "good practice" comment...
Tk is correct that the electrical code allows conductors of different voltages to occupy the same enclosure wiring enclosure, cable or raceway as the long as all have insulation ratings equal to the maximum circuit voltage applied to any conductor within the wiring enclosure, cable or raceway. (NEC 300.2(C)(1))
But, as he has stated, "when necessary"... providing separate conduits for different systems and equipment improves safety and allows for more accurate identification when trouble shooting or adjusting circuits in areas that contain a large amount of equipment and/or distribution.
If working space is not limited then separation of different voltages and circuits is in my opinion a "good practice"...

Can I put a ceiling light in my closet by first connecting to a plug in then to a light switch then to the light fixture.
Thank You
Jack [email protected]

[QUOTE=jack82;3313626]can I put a ceiling light in my closet by first connecting to a plug in then to a light switch then to the light fixture.
Thank You
Jack
P.S.
I was told that I can not do that but I do not know why I can't

Jack,
Instead of entering an old thread, please post this to the main page.