ECN Forum Forums General Topics of the Trade General Discussion Area 3 Phase Delta - Neutral required?

GROVER;

In a nutshell, if the connected loads do not require a Circuit which includes the System Grounded Conductor (there are no L-N Loads), the Grounded Conductor is not required to be brought past the point of initial Bonding to the GES (Grounding Electrode System).

From what I am interpreting this topic, it appears your Client has (2) 480Y/277V, 750KW Generators.

Is the plan to have both Gennys sync'ed, running in Parallel - then isolate One Genny if mechanical failure occurs;
or will One of the Two Genny be kept stand-by + isolated until needed?
(just curious)

I think I have an idea of the System Transfer action planned.
The Switchgear has (or will have) a section with a Manual Transfer Switch, and the Genny(s) connect to the gear via cords?

Anyhow, If there will be any L-N (277V) loads to be driven when the System is powered by the Gennys - such as during utility outages, then bring the Star-Point Common Grounded Conductor to the Gear, along with the (3) Ungrounded Conductors + an EGC.

If the Gennys ("Generators") are Delta Connected, there will not be a "Neutral"; only a Grounded Conductor (if Corner Grounded), or a Center Tap.
In the case of the Corner Grounded Delta, definitely bring the Grounded Conductor - as it will be Phase "B".
Also bring an EGC.
If Center Tapped, bring all (3) Ungrounded Conductors, along with an EGC bonded to the Center Tap + GES.

I attached Two Images of Switchgear containing a MTS (Manual Transfer Switch) + Genny Cord Whips, for reference.

Let us know the details and such.

Scott