Redsy,
There's at least 4 ways to connect a Delta. That's why it's REAL difficult to answer his question.
Reading his profile, he's an industrial engineer, so he could have nearly anything under the sun.
1 - 3 wire ungrounded. Very sensitive industrial equipment, hospital type situations. Voltage fluctuates without ground reference. Rare
2 - 3 wire grounded. Don't use the neutral, same equipment as above but with stable ground reference. You would render a high leg with this, but with no neutral, it would not matter, but you would read 208 to ground from B phase ( or 198 if it is a 230 volt system)
3 - 4 wire center tap ground. Use the neutral, this is the one, of course, that creates the high leg.
4 - 4 wire corner ground (there can also be 3 wire corner grounds) the wierdest of the bunch and danged rare, usually industrial, never seen one around Wash. DC (no industry) but worked 'em a lot in Baltimore and Richmond.
Then you've got open or closed delta.
Only on one of those would your meter register 0 to ground on one phase. The center tap would be A to G= 120, C to G=120, B to G= 208 (or phase to ground voltage from A or C phase times 1.73)
I have not hit my books since reading his question, with the voltage reference he gave, it is also possible he's dealing with an old Scott type connection, or 2 phase. He would have 4 hot wires on this system normally. Or to put that another way, typically he would have 4, there are 2 wire Scotts as well.
[This message has been edited by George Corron (edited 06-08-2002).]
