# 690 Volts 3 phase - One phase measured to ground



## GC11 (Oct 6, 2015)

I know that 690 is an uncommon voltage, but I'm wondering if anyone can tell me what one phase to ground would read on a voltage meter. Phase to Phase the voltage would still be 690V


----------



## Big John (May 23, 2010)

If this is a wye, it would be the same as all other wyes: L-L voltage/1.732, which in your case is 398V. 

I'm gonna go out o a limb and say there won't be a solid phase-to-ground voltage. Nothing would be designed to run on those single-phase values so it's likely ungrounded delta.


----------



## Lone Crapshooter (Nov 8, 2008)

I have seen strange voltages like that on our ungrounded systems with the light bulb ground detection and one of the bulbs on each phase would be open.The line to line voltage would still be 480 volts.

LC


----------

