Rotary phase converter: local ground or all the way to the panel?
 

On 2008-02-27, rpseguin wrote:

Given the cost of copper wire these days, my inclination is to run
just the two hots to the panel and to put a grounding rod close up to
the garage and run a local ground to it.

That is illegal and unsafe. I assume the "primary" side is a 240V
motor? You need an equipment ground conductor all the way back to the
240V service. If one of the hots shorts out to the motor case, for
example, you need this bonding path to carry enough current to trip
the breaker. You can not rely on the earth for the bonding path, its
resistance is too high.

As for the secondary side, you need to look up in the NEC how to wire
a "separately derived system". You can also look up how to wire motor
loads to determine the size of the feeder conductors for the primary
side.

Cheers, Wayne