Can rigid PVC conduit be used for branch circuits inside of a building?

Answer for USA, Canada and countries running a 60 Hz supply service.

Generally yes.

When installed where exposed to physical damage you must use Schedule 80 PVC. Most PVC is Schedule 40.

It should not be installed inside fire-rated walls.

It cannot be installed in theaters or similar assembly areas, exposed or concealed, except as provided specifically by code sections 518.4 or 520.5.

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As always, if you are in doubt about what to do, the best advice anyone should give you is to call a licensed electrician to advise what work is needed.

Before you do any work yourself,

on electrical circuits, equipment or appliances,

always use a test meter to ensure the circuit is, in fact, de-energized.

IF YOU ARE NOT ALREADY SURE YOU CAN DO THIS JOB

SAFELY AND COMPETENTLY

REFER THIS WORK TO QUALIFIED PROFESSIONALS.