Which receptacle-box combination will require a grounding jumper from the receptacle to the box?

In this scenario, it is important to understand the role of grounding in electrical systems and the specific conditions under which grounding is necessary. Grounding jumpers are typically required when there is a potential for the receptacle or the box to become energized due to faults or malfunctions, and when bonding between conductive parts is essential.

In this question, the choice stating that none of the combinations require a grounding jumper is based on the fact that all options presented involve either boxes designed for self-grounding receptacles or types of installations where the grounding requirements are inherently satisfied by the design or installation practice.

For instance, a self-grounding receptacle connected to a properly grounded metal box typically does not need an additional grounding jumper, as the receptacle effectively grounds itself through the box. Likewise, the surface-mounted "bell" box and handy box mentioned may also have features that ensure they are already effectively grounded or would not present a situation where bonding through a separate jumper is necessary.

Thus, due to the nature of the specified receptacle-box combinations, additional grounding jumpers are unnecessary in these particular installations, leading to the conclusion that none of the setups require a grounding jumper. This understanding is vital for ensuring safety and compliance with the National Electrical Code (NEC) in