Can Leviton USB In-Wall Chargers be used downstream from a GFCI? May 16, 2024 15:11 Updated Follow Yes, they can be used in locations downstream from GFCIs to ensure the outlet is protected from ground-faults. Related articles Why are wire leads used instead of screws on the GUAC1 and GUAC2 GFCI USB devices? Do the Leviton USB In-Wall Chargers have a breakoff tab for split power applications? Can I use a Leviton pop-up floorbox receptacle in a countertop application?