Pole mounted lighting questions (like in a parking lot):
I always thought that to connect HID lights to a 3 phase circuit that a fuse was required at the light, but I now think I am wrong. Am I?
What is a practical limit to wire size. I usually say #6 for a 30A circuit, but sometimes the voltage drop is too great, but larger wire is not as practical. What do you usually see?

Sounds like you're describing this mornings' job....

HID pole lights, 30 amp circuit.

Larger wires / feed wires joined to #10 wires in the pole base, with NSI type connectors. I was there adding fuses to these 480v. lights.

While not require, AFIK, they are a good idea. One reason is to make it so much easier to locate problems later on- and reduce the chances of a dying bulb tripping the breaker.