# Generator to Transformer



## active1 (Dec 29, 2009)

We do it all the time for shows.
Think the gens are always just ordered 480v.
For a 3P 4 wires are run to a disco for the 
primary side.
Disco because the gen has a larger OCP than what's needed and normally serves other loads.
Then 4 wire to the XFMR.
XFMR wired like normal.
Secondary out 5 wires to panel board.
Secondary OCP may be done several ways.


----------



## paulengr (Oct 8, 2017)

Toreand said:


> How common is it to see a wye load generator used to supply a delta/wye transformer?
> 
> The generator produces a 480v 3phase 4wire load where the line wires are feeding a 480v delta primary (no neutral) with a 208v wye secondary.
> 
> Are there any concerns about the grounding of the two wye neutral points here?


That's the industrial standard. There is no ground seen through the transformer so the secondary is a separately derived system. Both sides need their own system bonding jumper (grounding). With a generator if you are only feeding part of the system through an ATS you have a separate grounded neutral that switches, too so you need 4 wire wye distribution on both sides.

There are some cases where small portable generators do not need grounding so pay close attention to the Code because it's highly unlikely to apply. I install a few of these per year.

Sent from my SM-T350 using Tapatalk


----------

