15 kVa Transformer Hookup?

If the transformer is not grounded; in the event of earthfault on any of the transformer phase connectors, the healty phase voltage if you happen to measure it shoots up: objectionable isn't it.

It seem you have grossly misinterpreted the earthing requirements given by the vendors; Transformer neutral is to be first connected with an earthing rod/pit and than carry out bonding with transfer switch and metal enclosuere of the UPS, while the internal earth of UPS at the output sourcing (electonic card earth) should have a distinly seperate earth system.

Connecting the out sourcing of UPS to the electrical erthing bus will provide considerable distortion to the 4-20 milliamp instrument fuction as well as DCS (if has been installed) to frequently disrupt the proper functioning of the Control Room.

The transformer, transfer switch are independantly grounded to the ground bus va #2 . The system is all bounded together with the #6 in the TECK Cable. And there is an ind. ground wire, #2 from the neutral-ground jumper on the secondary of the UPS to ground.

It has been installed according to manufacture specs and my own common sense.

Just was not sure why I needed to ground the jumper on the tranny.

Thank you for your info, I will check it out.