jar546
CBO
You are called to inspect the installation of new outdoor post lights (2) at the entrance to a driveway. The electrician ran 12/2 UF cable for voltage drop on this 120vac, 15A circuit that is protected in the main panel with a 15A OCPD. You already inspected the trench.
While out at the lights you notice that the contractor has installed a ground rod at each of the 2 lights. When you inquire as to why, he explains that after backfill was completed, the bare copper grounding conductor was accidentally broken off where it enters the weather proof junction box and rather than go through the expense of running a new wire, he decided to install a ground rod at each fixture and connect the green ground of the fixture directly to the ground rods so that there is a path to ground. He states that he did a ground resistance test and showed you the print out that confirms each rod has 15 Ohms resistance.
1) Is this an acceptable, compliant installation? If not, what would you cite?
2) What is the maximum fault current that can flow back to the power supply?
3) Is the fault current enough to trip the OCPD?
As usual, please don't read into the questions. All of the information you need is provided in the example and there is nothing else that you need to know other than what is in front of you.
While out at the lights you notice that the contractor has installed a ground rod at each of the 2 lights. When you inquire as to why, he explains that after backfill was completed, the bare copper grounding conductor was accidentally broken off where it enters the weather proof junction box and rather than go through the expense of running a new wire, he decided to install a ground rod at each fixture and connect the green ground of the fixture directly to the ground rods so that there is a path to ground. He states that he did a ground resistance test and showed you the print out that confirms each rod has 15 Ohms resistance.
1) Is this an acceptable, compliant installation? If not, what would you cite?
2) What is the maximum fault current that can flow back to the power supply?
3) Is the fault current enough to trip the OCPD?
As usual, please don't read into the questions. All of the information you need is provided in the example and there is nothing else that you need to know other than what is in front of you.
