ghaydon
New member
- Location
- Austin, TX
Definition of "earth" and "direct contact with earth" according to the NEC
The NEC talks about grounding electrodes being in "direct contact with the earth". It also mentions "earth" in several places. However, it never defines what these terms mean. Here is my situation:
A contractor installed an electrical system in a complex (65 load centers total) in 2005. At each load center, a metal water pipe was used as the grounding electrode. Each metal water pipe was buried in pea gravel (not dirt). At each load center, the grounding electrode is supplemented by a ground rod as required by 250.53(D).
The measured resistance of the grounding electrode conductors range from 16 ohms to almost 1100 ohms at each load center. Other than the measurements, is there a way to prove that the installation (burying the metal water pipe in gravel) was incorrect? The NEC does not define earth or soil types used as earth.
Thank you,
The NEC talks about grounding electrodes being in "direct contact with the earth". It also mentions "earth" in several places. However, it never defines what these terms mean. Here is my situation:
A contractor installed an electrical system in a complex (65 load centers total) in 2005. At each load center, a metal water pipe was used as the grounding electrode. Each metal water pipe was buried in pea gravel (not dirt). At each load center, the grounding electrode is supplemented by a ground rod as required by 250.53(D).
The measured resistance of the grounding electrode conductors range from 16 ohms to almost 1100 ohms at each load center. Other than the measurements, is there a way to prove that the installation (burying the metal water pipe in gravel) was incorrect? The NEC does not define earth or soil types used as earth.
Thank you,
