480v grounded 3 phase serving an oil well pump jack

[amerijet]

I am located in a state that has adopted UEC however it is only licensed and inspected by cities that require it. Hence the problem. I have seen older oil wells that have a 3 wire grounded phase 480 to ground reference on two legs and 0 on the other phase usually B phase.
I have no fourth wire coming as a low impedance circuit to the main disconnect at the utility pole hence the ECG is only tied to the grounding rods.
I have talked with inspectors in the cities, power companies and other electricians and don't really get any feedback on this subject. I ve milled through NEC and feel 4th wire or changing to single phase is the only real option here to protect myself and others. Any feedback on this would be extremely helpful!

 

[retirede]

Protect from what? As long as you have (properly installed) overcurrent protection at the well, it’s not unsafe. It’s just like the 3 wire service entrance to your house.

 

[don_resqcapt19]

Yes, after the main disconnect, an EGC is required. If one of the ungrounded conductors would fault to any metal part, you would have 480 volts from that part to the earth. There is no fault clearing path.
The grounding electrodes should be at the service disconnect connected to the grounded circuit conductor, and the EGC originates at that point.
Are the circuit conductors between the service disconnect and the equipment in metal conduit? If so, the metal conduit would be the EGC.

 

[winnie]

Please clarify: is the EGC only tied to grounding rods, or is the EGC tied to both grounding rods and the Grounded Conductor from the utility? Is this supposed to be an ungrounded system that happens to have a fault, or is this supposed to be a corner grounded delta?

If the EGC is properly bonded to the grounded conductor, then you have a low impedance circuit for fault current. This is exactly how most utility service drops work; you have a single grounded circuit conductor that also functions as the fault current return path from the utility to the service, then at the service you have the EGC (and ground rods) connected to the grounded circuit conductor, and from the service onwards you have separate grounded circuit conductors and EGCs. This is(was?) sometimes permitted for some feeders, and I'm not going into the specifics of when feeders are permitted without a separate EGC; the key point is that in these situations the EGCs are bonded to the grounded conductor.

Don't get tripped up by the fact that the grounded conductor might not be the neutral. It is still a conductor intentionally held at ground potential by connection to grounding electrodes and bonding to the EGCs.

A corner grounded delta system, where the EGCs are properly bonded to the grounded conductor has a perfectly fine fault current path.

Now: if you have a corner grounded delta system, and then have EGCs that are only connected to ground electrodes without the necessary bonding, then you do have a safety issue, one that needs to be fixed with proper bonding.