I think if it's single voltage - in other words, ungrounded straight 480v. you only need a 3 pole transfer switch. You will still be bringing an GEC from the generator to the transfer switch to ground the equipment. As I recall there is a need for ground indicator lights but I don't know where I saw that. Also typically ungrounded systems are Delta not Wye. You can check to see if you have any voltage between any of the 3 legs and Ground to find out if it's a grounded system. No insults intended Ernie cause I'm sure you already have done this. Also look in Soares Grounding 8th Ed. p. 43-51 for a brief overview of ungrounded systems and pictures too
