Receptacles mounted in boxes flush with the finished surface or projecting from the finished surface must be installed so that the mounting yoke or strap is held rigidly against which component?

• A. Box or Box Cover
• B. Faceplate
• C. Wall Stud
• D. Grounding Conductor

Answer: (A)

The mounting yoke or strap must be pressed firmly against the box or box cover because that solid backing provides the actual anchor for the receptacle. When you tighten the mounting screws, the device is drawn against the rigid support of the electrical box, which keeps it stable, properly aligned with the finished surface, and prevents movement that could loosen connections or crack the wall finish. The faceplate is only a cosmetic cover and does not supply the structural support needed for mounting. The grounding conductor is part of safety bonding and has no role in providing mechanical backing. A wall stud isn’t the correct backing for the mounted device either, since the receptacle relies on the box itself to carry the load and keep the device in the correct position.