I have a bathroom which shares a lighting circuit with other living areas. In California this is required to be AFCI protected, but not required to be GFCI protected (receptacles are on a separate dedicated circuit and GFCI protected)

However, with light switches in close proximity to sinks and showers what is considered best practice?

Should I replace my AFCI lighting breaker with a DF breaker offering both protections?

(Square D QO)

The switches and receptacles are grounded. These switches are in a plastic box with a plastic face plate.

  • Are the switches grounded? If they are, I would think there would be no need for GFCI on the switches. Jun 22, 2020 at 11:36
  • 1
    Also for this location I would think the switch plate should be plastic. Metallic switch plates are allowed if the switch itself is grounded, but in this situation I would have plastic. Jun 22, 2020 at 12:36

1 Answer 1


I would not use a dual function breaker on the lighting for several reasons. The first being the lighting circuit usually has the fan and possibly a humidistat , timer I have had trouble with GFCI’s tripping and fans my best guess is the emf on start and turn off is the cause not always but often enough that several of the owners that had me install them had me remove them.
This is the main reason a minor reason is electronic breakers tend to have a shorter life than common breakers dual function just one more thing to fail. As far as the switch electrical contacts these are isolated from the metal, this and the fact that it is grounded really is the protection needed if the worst happens the ground will cause the breaker to trip.

I do not see an advantage in this case and only more costs and possible failures.

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