Transformer Connections

[wr6021]

I'm working on a project in an area that I'm not familiar with the utility or their distribution voltage. The utility confirmed the voltage as 8320GRDY/480. So do I connect with a Wye-Wye transformer or a Delta-Wye and connect the grounds/neutrals together?

 

[texie]

I'm working on a project in an area that I'm not familiar with the utility or their distribution voltage. The utility confirmed the voltage as 8320GRDY/480. So do I connect with a Wye-Wye transformer or a Delta-Wye and connect the grounds/neutrals together?

I'm not real clear on your question. You seem to be implying that they are giving you a 480Y/277 service and you want to step down to 208Y/120. The POCOs primary is irrelevant to you. You would just use a standard 480 delta X 208Y/120 transformer.
Maybe I don't understand your question.(?)

 

[Smart $]

Sounds like you are installing a service transformer which the primary connects directly to the utility distribution lines.

Sounds like the utility lines are 13.8kV_LL wye running a bit hot, which would be put it a tad over 8kV_LN.

You can use either a Dy, or Yy with neutrals tied together, all subject to POCO requirements. You should confirm with them.

 

[wr6021]

Sorry missed a 0 on the utility voltage. The utility voltage is 8320GRDY/4800 and I'm stepping down to 480Y/277.

 

[Smart $]

Sorry missed a 0 on the utility voltage. The utility voltage is 8320GRDY/4800 and I'm stepping down to 480Y/277.

Still the same reply... just different.

Really, the voltage changes but that's it.