Can you put a 15a gfci on a 20a circuit?
A 15 Amp receptacle can be supplied with a 20 Amp circuit. If only one 15 Amp receptacle is used in the circuit, there is no reason why it can't be done. Most receptacles have a potential of up to 30 Amps.
Let's Get It Fixed!
HomeX virtual experts will assess your issue (for free!) and can resolve simple problems.