Does it matter if a 30A dryer is plugged into a 30A outlet through a 50A pigtail?

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

If the current draw through the circuit is less than the rated current of the circuit then there is no problem. In this case if it is a 30 Amp dryer
  • fed through a 50 amp outlet on a pigtail that has a 30 Amp plug
  • plugged into a 30 Amp outlet
  • on a circuit protected by a 30 Amp breaker

    No worries!

<><><>

It is wise to place an over-current device (fuses or circuit breakers) in your pigtail, though.

-EDIT- Only if it's a 50A outlet. If you have 50A wiring on a 30A breaker you are quite safe.

<><><>

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.