I have a 800 amp 277/480 volt mcc panel running a small plant,in the same room with the mcc panel i am adding a 30 kva transformer 480-208/120 for a subpanel,out of the mcc panel,i tapped the main nippled out of the mcc with a galv.nipple bond bushing on each end to a 40 amp disconnect, i ran 4 #8 3ph and a ground. in 1" sealtight with bond bushings on each end, i ran 8'to the transformer 3ph and the ground that is connected to the transformer frame. out of the transformer to the sub panel with 10' of pvc with 4 #2 AND 1 #6 ground, bonding done in the subpanel, #6 grounding electrode to plant steel frame.

Lite,

Did you tie in to your Xo connection on the secondary. All steel needs to be bonded as well.

Steve

just the neutral to xo there is a strap from xo to the transformer frame,bonding is done in the panel. could i have just run the 3ph and the neutral and not the ground from the trans. to the panel just like a incoming service, or was it right to run the ground, now i look at it there are 2 paths of ground coming from the 120/208 panel (1) the neutral,(2)the ground.

You can't make a bond in both the transformer and the panel on a SDS. You only do it at one location. No matter where you make the bond, there has to be a path from the transformer case to XO. If you bond at the transformer, the path is direct from the case to XO. If you bond at the panel, the path from the case is via the equipment bonding jumper to the panel. In either case an equipment bonding jumper is required between the transformer and the panel.
Don

so the bonding strap that came with the transformer xo to the case has to be removed when bonding in the panel.

Yes. Look at 250.30(A)(1).
Don