Three phase - Page 2 - Electrician Talk - Professional Electrical Contractors Forum

JRaef · 05-03-2012, 11:00 AM

Quote:

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.

nolabama · 05-03-2012, 08:41 PM

Quote:

Originally Posted by JRaef

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.

Depending on the parish, he is prolly right. Strange combos have been delivered by older poco in this area.

ampman · 05-03-2012, 08:46 PM

Quote:

Originally Posted by Wirenuting

With "Your" time and "Their" money, it looks like an easy solution.

that has to be the post of the year -- do you mind if i use it