Looking into this issue deeper and assuming it is a 480V corner grounded delta system, here are some additional questions:
The service disconnect is a fused disconnect. It is my understanding the grounded phase should be a no-blow fuse, is that correct and what is the code reference?
240.22 prohibits the use of a fuse in the grounded conductor
Next, should the grounded phase be jumpered to the ground bar in the service disconnect with only 3 wires coming down pole or should it be bonded at the pole xfmr and brought down similar to the neutral with 4-wires to the service disconnect?
The grounded service conductor must be connected to a main bonding jumper and to a grounding electrode conductor at the service disconnect.
From the service disconnect on, I understand that all 3-pole CB's should be straight 480V rated. If fuses are used, do all 3 phases get fused or does the grounded phase remain no-blow?
240.22 does permit the use of 3 pole breakers for this system, and you are correct that they must be straight rated at 480 volts. 480/277 volt breakers are not permitted. If you are using a fuse for motor overload protection, you would be permitted to put a fuse in the grounded circuit conductor, also part of the rule in 240.22.
When wiring to a motor (or any other 3-phase load), does the motor need to be specifically rated for 480V delta?
The motor only cares about the line to line voltage. No special motor is required.
How about the motor starter with overloads, does it specifically need to be delta rated? sometimes motor startes have fuses instead of CBs.
Nothing special is required for the starter.
I have read that on a delta system, you only need to use 2-pole CB's. How does the grounded leg get sized and wired as it works its way from a motor back to the starter, back to a distribution panel, then back to the service?
For this system the grounded conductor is really a phase conductor and will be the same size as the ungrounded conductors. You can, in some case use single phase panels and breakers for this system. In that case the two ungrounded conductors are connected to the two pole breaker and the grounded conductor would be connected to the neutral bar. The installation would look just like a 120/240 volt system, but of course with 480 volt rated panels and breakers. The motor still needs overload protection for all 3 phases so it would still be a standard starter.
Does anybody have a photo reference of a properly wired 480V corner grounded delta service?
Having a little difficulty with the understanding the concept of getting 3-phase power at a motor when 1 phase is grounded, does the grounded phase actually have voltage on it? Its almost like you can touch it and not get zapped similar to touching ground since at the same potential.
The motor is only looking at the voltages between the 3 conductors, it does not even see the voltage to ground. The motor does not know and does not care what type of system it is connected to. For the motor, an ungrounded system, a corner grounded system, and a wye system are all the same as long as you have the correct voltage.
Don't forget that the grounded conductor is a grounded conductor covered by Article 200 and it must be identified exactly the same as a neutral, that is the conductor must be white or gray.