I had something new happen to me last night, I've asked two other electricians and they don't have an answer for me either. I had a 3 phase, 4 wire 600 volt splitter, and I needed to power a 347 volt light, while I changed a single phase 120/240 volt x-former to a three phase 120/208. When I turned on the disconnect for the light, the light didn't come on. I checked the voltage and found 120 volts on the phase I was hooked to, I found 780 volts on another phase and over 800 volts on the next phase. I tried to hook the light to a different phase and had the smae results. With no lights hooked up, everything is normal. Has anyone seen this before. Thanks.
It sounds like a loose connection somewhere. Possibly in the splitter or even all the way back to the poco's xfmr. You said 4 wire, so it could be the neutral, I've seen similar results with a loose neutral before.
I agree. Sounds like you are reading the resultant voltage of Capacitive Coupling (if you are reading L-G and getting the wierd readings as stated).
Make sure the Common Grounded Conductor (AKA "neutral") is connected properly between source and load(s). Also make sure the Equipment Grounding Conductor is connected properly between source and load(s).
Sounds like you have both - an open Noodle and an open Eq. Grounding Conductor, only the EGC is physically connected to earth ground somewhere, but not connected to the source's Grounded Conductor.
Let us know the outcome!
Scott " 35 " Thompson Just Say NO To Green Eggs And Ham!
Another thought or two.... Are the ballast taps marked correctly, is the ballast capacitor hooked up correctly, does the voltage change when the lamp is in or out of the socket? I think there are drawings in the technical reference section.