I understand why Yoopersup is concerned with this setup.
It appears as if there is no _Direct Bond_ between the Metallic Enclosures on the Separately Derived System (SDS), and the Star point of the Transformer Array.
If this is accurate, then the SDS is an Ungrounded 480V 3 Phase 3 Wire; instead of being a Delta Configuration, it is a Wye Configuration.
As long as there is a local Grounding Electrode System bonded to the Metallic Enclosures on the SDS, the System is safe and conforms to NEC Article 250.
HOWEVER...
If the Star Point is tapped, with a 4th Conductor brought down from the Wye Network to the first Disconnect... AND this Conductor is usable for a "Dual Voltage SDS" (480Y/277V 3 Ph. 4 Wire), then the tap from the Star Point shall be a Grounded Conductor for the SDS, requiring all the Bonding and similar stuff.
This Grounded Conductor would need to be brought to the first "Supply Point"
Other Possible Grounding Options:A: Star Point Ground Bonded At Pole...
The SDS might be Ground Bonded at the Pole, via a Grounding Electrode Conductor (GEC) directly Bonded to the Star Point at the Secondary.
Same GEC is also bonded to metallic enclosures on the SDS.
B: Corner Grounded SDS...
One of the Three Phase Lines may be Grounded either at the Pole, or at the first Disconnect / Supply Point.
C: Impedance Grounded System...
Either via an introduced Impedance between Grounding Electrode System (GES) and the Star Point of the Transformer Network (proper),
or;
No Physical Connection between the GES and the Star Point of the Pole Mounted Transformers - AKA Impedance of the Dirt. (not preferred, but have seen several of these!)
FYI: The "Star Point" is the common termination of all Three Secondary "X2" leads, from all Three Transformers.
![[Linked Image]](https://www.electrical-contractor.net/forums/gallery/24/full/255.png)
The Yellow Common Connection on the Secondary side of this Drawing is the "Star Point". It is where the Common Grounded "Neutral" Conductor is derived for the 4 Wire Wye.
* BTW Yoopersup: Are the Transformers for this System connected as shown in the above drawing...,
or;
like one of the configurations found on the following pages:
3 Phase 3 Wire Wye3 Phase 3 Wire Closed Delta(click on the blue underlined text to jump to that page).
-- Scott