Originally Posted by Theriot
A parish gym called for me to run power to two 20 ton a/c 3 phase units that will be installed tomorrow. Here's a pic of their three phase main disconnect.
It is remotely possible that you have a corner grounded 3 phase delta system there. You are only required to have fuses on the UNGROUNDED conductors. I know the one set of wires eventually has white tape on it, DOWNSTREAM of the splitter block, but I have seen that mistake made before by someone who didn't know about corner grounded delta services and assumed it was a neutral. A simple test is to measure the line to line voltage, not the line to ground voltages.