Distinguish between a bonding jumper and a grounding electrode conductor; what is each used for?

• A. Bonding jumper connects the system to the earth electrode.
• B. Bonding jumper connects equipment grounding to the neutral.
• C. Bonding jumper ties metal parts together to equalize potential; grounding electrode conductor connects the system to the earth electrode.
• D. Bonding jumper is the same as the grounding electrode conductor.

Answer: (C)

The main idea is keeping metal parts at the same potential while also giving the system a reference to earth. A bonding jumper is used to tie together exposed metal parts—such as enclosures, raceways, and piping—so they float at the same electrical potential. This equalizes voltage between parts that could be touched simultaneously and helps ensure that a fault involving one piece of metal won’t leave another piece at a dangerous voltage.

The grounding electrode conductor, on the other hand, connects the electrical system to the earth through a grounding electrode like a ground rod or a bonded water pipe. Its purpose is to establish a reference point for the system voltage and provide a low-impedance path to dissipate fault currents into the earth, which helps protective devices operate correctly.

So, the bonding jumper’s job is to equalize potential among metal parts; the grounding electrode conductor’s job is to connect the system to the earth.