You only really need one, the first outlet in series should be GFCI and then there is a “load” side and anything connected to that is also protected. If you aren’t sure, you can get a tester to trigger a GFCI fault and if it is connected to one, it will trip.
You only really need one, the first outlet in series should be GFCI and then there is a “load” side and anything connected to that is also protected. If you aren’t sure, you can get a tester to trigger a GFCI fault and if it is connected to one, it will trip.