Electrician's Licensing Practice Exam

Is it permissible under NEC to ground gas pipes to existing grounded water pipes?

1. Yes, if the water pipes are grounded

2. No, it's not allowed

3. Yes, regardless of grounding

4. Only in residential installations

The correct answer is: Yes, if the water pipes are grounded

Grounding gas pipes to existing grounded water pipes is permissible under the National Electrical Code (NEC) as long as those water pipes are themselves properly grounded. This practice is grounded in the principle that a grounding system must provide a low-resistance path to the earth to ensure safety and stability in the electrical system. When water pipes are bonded and grounded, they can serve as an effective grounding electrode for the gas piping system. This connection can help to ensure that any induced voltage or fault condition is safely dissipated, reducing the risk of electrical hazards, including potential shock risks or fire hazards associated with gas leaks igniting. The NEC allows such connections because they contribute to the overall integrity of the grounding system while ensuring that all metallic systems in the building remain at the same electrical potential, fostering safety and functionality. However, it is important to abide by local code amendments and any specific requirements laid out in your jurisdiction, as they may impose additional requirements regarding the bonding and grounding of gas and water pipes.