480v grounded 3 phase serving an oil well pump jack

[ActionDave]

I'm predicting it's a corner grounded service properly wired and the problem is with the equipment.

 

[hillbilly1]

In the picture, you can see each transformer has a wire connected to its tank. This wire is spliced to the utility grounded conductor and to what looks like a white conductor. It then looks like 2 black and 1 white conductor go down the pole as service entrance conductors. We don't see the service entrance equipment, which is where the GEC is likely located.

Looks like from the picture, it is corner grounded at the pole, though we can’t see it, the ground looks to loop around and terminate at each lug on the back side of the transformers, so there may, or may not be a GEC connected at the service, but as you say, we don’t have pictures of the service.