Equipment Ground conductor required on Delta secondary systems

[mull982]

For MV or LV systems that are fed from a ungrounded delta secondary are there any grounding requirements for EGC's or ground wires to be run with the phase conductors similar to what you would have with a grounded system?

I understand that ungrounded delta systems will not have any fault current flow for a L-G fault and thus no need for an EGC, but I wanted to make sure that I'm not missing anything in the NEC that requires a ground to be run with the phase conductors. The way I see it just the phase conductors will be run between the transformer secondary and the first disconnecting means. Is this correct?

 

[GoldDigger]

The fact that there is no neutral or other grounded conductor does not take away the requirement for an EGC.
And some sort of return path is necessary to be able to trigger a ground detector, even if no substantial fault current will flow on the first fault.
A first fault to earth and a second fault to exposed metal can create a hazardous situation unless the exposed metal is metallically bonded to your GES. Even then, it might not trip an OCPD, but there's not much more you can do except try to repair the first fault before the second one occurs.

 

[david luchini]

See 250.24(E), 250.30(B) and 250.130(B).