An unspliced __ that is sized based on the derived phase conductors shall be used to connect the grounded conductor and the supply-side bonding jumper, or the equipment grounding conductor, or both, at a separately derived system.
system bonding jumper
equipment grounding conductor
grounded conductor
grounding electrode conductor
The Correct Answer and Explanation is:
Correct Answer: system bonding jumper
Explanation:
In electrical systems, particularly separately derived systems (such as transformers that are isolated from the main power source), proper grounding and bonding are essential for safety, fault current return path, and system functionality.
The question focuses on the conductor that connects the grounded conductor (commonly the neutral), the supply-side bonding jumper, and possibly the equipment grounding conductor. The key phrase in the question is: “used to connect the grounded conductor and the supply-side bonding jumper, or the equipment grounding conductor, or both.”
This defines the system bonding jumper.
What is a System Bonding Jumper?
A system bonding jumper is the critical conductor that connects the grounded conductor (neutral) of a separately derived system to the equipment grounding conductor and/or the metal parts of the electrical equipment. It ensures that the grounded conductor is connected to the grounding system to facilitate the clearing of ground faults by providing a low-impedance path back to the source.
According to the National Electrical Code (NEC) Article 250.30(A)(1), for separately derived systems:
- A system bonding jumper must be installed at the source or the first disconnecting means.
- This jumper must be unspliced and sized based on the derived ungrounded conductors (phase conductors), as per NEC Table 250.66.
Other Options Explained:
- Equipment Grounding Conductor (EGC): Connects equipment enclosures to the grounding system, but not directly responsible for bonding the grounded conductor to the grounding system.
- Grounded Conductor: The neutral in a system, but it needs to be bonded to ground via a system bonding jumper.
- Grounding Electrode Conductor (GEC): Connects the grounding electrode (e.g., ground rod) to the system but does not serve the bonding function described in the question.
Conclusion:
In a separately derived system, the system bonding jumper is the correct, unspliced conductor that ensures proper connection between the grounded conductor, supply-side bonding jumper, and/or equipment grounding conductor.