Master Electrician Exam (NEC)Grounding and BondingEasy
A master electrician is installing a new 200A, 120/240V, single-phase service. The grounding electrode system consists of a metal underground water pipe and a supplemental ground rod. Which of the following statements is correct regarding the connection of the grounding electrode conductor (GEC) to these electrodes?
- AThe GEC must be connected to the ground rod first, then to the water pipe.
- BThe GEC only needs to be connected to the water pipe; the ground rod is merely supplemental and does not require a GEC connection.
- CThe GEC must be connected to the water pipe and then to the ground rod, or vice versa, in a continuous run or with suitable splices.
- DSeparate GECs are required for each electrode, each sized independently.
Show answer & explanationAnswer & explanation
Correct answer: C. The GEC must be connected to the water pipe and then to the ground rod, or vice versa, in a continuous run or with suitable splices.
According to NEC 250.64(C), grounding electrode conductors that are required to be connected to more than one grounding electrode can be run to a common location and interconnected, or they can be run to one electrode and then continued to other electrodes by one or more splices or connections.
Why the other options are wrong
- A. The order of connection is not mandated by the NEC, as long as all electrodes are properly connected.
- B. Incorrect. Both the metal underground water pipe and the supplemental ground rod must be effectively connected to the GEC, as per NEC 250.53(D)(2).
- D. Incorrect. A single GEC, sized for the largest ungrounded service conductor, can be used to connect to multiple electrodes.
GEC Connections to Multiple Electrodes
When multiple grounding electrodes are used, the GEC can be connected to them in a continuous run or with suitable splices, ensuring all electrodes are effectively bonded.
- GEC can be continuous or spliced.
- No specific order of connection required.
- All electrodes must be connected.
Memory trick: GEC connects all, standing tall.