Medan GFCI-skydd inte alls behövs på en 50A-strömkrets - krävs endast 15 och 20A-kärl som serverar köksdiskar enligt 210.8 (A):
(A) Dwelling Units. All 125-volt, single-phase, 15- and 20-ampere receptacles installed in the locations specified in 21O.8(A)(1) through (10) shall have ground-fault circuit-interrupter protection for personnel.
(6) Kitchens - where the receptacles are installed to serve the countertop surfaces
du kan installera jordfelsskydd på intervallkretsen med en tvåpoligt GFCI-brytare om du vill, eftersom du kör en separat jordkabel till apparaten - inget i kod förbjuder det , och det kan skydda ugnen mot skador som orsakats av fel på grund av jordbågar.
Observera att detta inte fungerar om du inte har en jordkabelkörning (det vill säga att du sätter in ett NEMA 10-uttag) - det här beror på undantaget till 250.140:
Exception: For existing branch-circuit installations only where an equipment grounding conductor is not present in the outlet or junction box, the frames of electric ranges, wall-mounted ovens, counter-mounted cooking units, clothes dryers, and outlet or junction boxes that are part of the circuit for these appliances shall be permitted to be connected to the grounded circuit conductor if all the following conditions are met.
(1) The supply circuit is 120/240-volt, single-phase, 3-wire; or 208Y/120- volt derived from a 3-phase, 4-wire, wye-connected system.
(2) The grounded conductor is not smaller than 10 AWG copper or 8 AWG aluminum.
(3) The grounded conductor is insulated, or the grounded conductor is uninsulated and part of a Type SE service-entrance cable and the branch circuit originates at the service equipment.
(4) Grounding contacts of receptacles furnished as part of the equipment are bonded to the equipment.