Delta Delta transformer grounding?

[ActionDave]

is it OK/acceptable to have two PE/EGC wires (in parallel) connecting the transformer to the power enclosure. one for the line side connector, and the other for the load side connector?

Yes, it's what is required.

I am seeing a lot of conflicting info on this as there could potentially be a ground loop created? If, i have to isolate the two, how do i do it? There will be like 10-feet of cable between them if its relevant?

You don't. Your voltages are isolated from each other by the transformer windings and the XO is derived from the secondary windings only, so there is no electrical connection for a ground loop. The EGC/PE is connected to everything on both sides of the transformer everywhere.

 

[emiller233]

Yes, it's what is required.


You don't. Your voltages are isolated from each other by the transformer windings and the XO is derived from the secondary windings only, so there is no electrical connection for a ground loop. The EGC/PE is connected to everything on both sides of the transformer everywhere.

ok, great! i think i'm finally starting to understand it all!
just to verify tho, it doesnt matter that i have both of these voltages inside of my power enclosure? thats where the circuit breakers/contactors are for both of these voltages. there is also a 208VAC service feed coming into this power enclosure, which will tie into the same PE/EGC grid

 

[ActionDave]

ok, great! i think i'm finally starting to understand it all!
just to verify tho, it doesnt matter that i have both of these voltages inside of my power enclosure? thats where the circuit breakers/contactors are for both of these voltages.

It's fine with me, and it's okay by the NEC. I don't design things though so I don't know about those rules.

there is also a 208VAC service feed coming into this power enclosure, which will tie into the same PE/EGC grid

Yes. EGC's don't carry normal current that is used by the equipment, they only exist to carry fault current and to connect to anything that might become energized by that fault.

 

[emiller233]

i can finally check this off of my to-do list!
thanks for all of the hlp!!!

 

[JayP99]

How are going to protect it or the worker...???

How are going to protect it or the worker...???

I just heard back from Eaton on the transformer. They said I can switch thistop the grounded 480/277 wye secondary for the same price, which puts me back to the grounding to meet a CSA/UL Listing (which is past my knowledge level)

the transformer will be sitting offline of our machine (right next to it due to weight)
there will be a connector on the cable going to the transformer on the Line Side(3 hot + ground)
there will be a connector on the cable going to the transformer on the Load Side(3 hot + ground)

There should now be a ground lug on the transformer chassis since we're switching to a WYE secondary. Do we just land the ground wires coming from both cables/connectors (the Line Side and the Load side) onto the ground lug and its good?

Transformer also isolates - are there provisions for protection on the load side?