Which conductor is typically bonded to earth to establish a reference potential?

Which conductor is typically bonded to earth to establish a reference potential?

• A. Grounding electrode conductor
• B. Neutral conductor
• C. Ungrounded conductor
• D. Equipment grounding conductor

Answer: (A)

The key idea is creating a stable reference point and a clear fault path by bonding the system to the earth. The conductor that does this is the grounding electrode conductor. It links the grounding electrode (such as a ground rod, clamp to a water pipe, or other approved earth connection) to the building’s grounding network. That bond to the earth establishes zero volts as the reference for the system and gives a low-impedance path for any fault current to flow to ground so protective devices trip quickly. The neutral conductor also relates to grounding in that it is bonded to earth at the service, but its primary role is to carry current during normal operation, not to establish the reference by itself. The equipment grounding conductor provides safety by connecting exposed metal parts back to the source, yet the direct bond to earth that sets the reference comes from the grounding electrode conductor. The ungrounded conductor is a live path and is not bonded to earth for reference.

The key idea is creating a stable reference point and a clear fault path by bonding the system to the earth. The conductor that does this is the grounding electrode conductor. It links the grounding electrode (such as a ground rod, clamp to a water pipe, or other approved earth connection) to the building’s grounding network. That bond to the earth establishes zero volts as the reference for the system and gives a low-impedance path for any fault current to flow to ground so protective devices trip quickly.

The neutral conductor also relates to grounding in that it is bonded to earth at the service, but its primary role is to carry current during normal operation, not to establish the reference by itself. The equipment grounding conductor provides safety by connecting exposed metal parts back to the source, yet the direct bond to earth that sets the reference comes from the grounding electrode conductor. The ungrounded conductor is a live path and is not bonded to earth for reference.