Service Grounding

[Irishelectric]

I am working on an old commercial building, it has a 200amp meter main its single phase 240v 3 wire. from the meter main to the panel there are only 3 wires, can i drive a ground rod at the panel or am i required to pull a ground wire from the meter main to the panel.

 

[don_resqcapt19]

You need an equipment grounding conductor between the main and the panel. The grounding electrode conductor must be connected at the main. Note, a metal raceway can serve as the required equipment grounding conductor.