240 - 240 & 240

[1793]

OK, I'm brain dead today so I need new life. I was on a job today and ran across a situation I need help with.

The disconnect, 20a, that feeds a 240v A/C outlet tests out as:
L1 - L2 = 240v
L1 - ground = 240v
L2 - ground = 240v

What type of Service configuration would yield these results?

 

[SEO]

Possibly a corner grounded delta.

 

[augie47]

Possibly a corner grounded delta.

almost has to be. Think of a 240 volt 3 phase with B phase grounded and your A/C is fed by A and C phases.

either that or sombody hooked the ground up really wrong

 

[1793]

Possibly a corner grounded delta.

I could come up with:

120/240v 3 phase four wire (Delta High leg)

120/208v 3 phase four wire (WYE Connected)

but forgot about the Corner-Grounded Delta

thanks