Faceplates, Box Covers, and Receptacle Replacement Rules
The finish stage closes up every box and trims out every device. Two areas the exam loves: what must cover a box, and the special rules when you replace an existing receptacle.
1. Every box gets covered — 314.25
Every outlet box must be closed with a cover, faceplate, lampholder, or luminaire canopy. (CEC 314.25) A junction box with no device still needs a blank cover — you can't leave it open.
2. Faceplates — 406.6
Receptacle faceplates must completely cover the opening and seat firmly against the mounting surface. (CEC 406.6) Metal faceplates must be connected to the equipment grounding conductor. (CEC 406.6(B))
3. Mounting — 406.5
Receptacles must be mounted rigidly, with the yoke held firmly to the finished surface (using the proper screws/box ears). (CEC 406.5)