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128+ Volts registering on a Furman Surge Protector

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Samuel Rees:
128+ Volts registering on a Furman Surge Protector at a venue in working at right now. It goes back and forth between "all lights lit" which seems to be 128V, and all lights flashing, which seemingly means above 128V. The "extreme voltage" light has not yet lit. I'm unaccustomed to high voltage - I've really only seen sagging mains voltage from current, or weird low vales. Not sure if there is anything I can do - is this something I can suggest the venue call and electrician or the power company about?

John Roberts {JR}:
Could be a loose neutral at the panel so when one side of the same phase gets loaded down, the other side rides up.

JR

Mike Sokol:

--- Quote from: John Roberts {JR} on November 17, 2013, 06:16:27 PM ---Could be a loose neutral at the panel so when one side of the same phase gets loaded down, the other side rides up.

JR

--- End quote ---
I agree. Does the voltage on your Furman "bounce up" when a bunch of stage lights are turned on? I've seen a loose or undersized neutral allow the voltage on the opposite side of the 120/240 split-phase panel jump up by as much as 10 volts when all the stage lights are up. And while undersized neutrals were less common on single-phase 120/240-volt panels, undersized neutrals were often done on industrial 3-phase 120/208 volt panels to save money since it was assumed that most loads would be things like 3-phase motors or leg-to-leg 208-volt heaters which don't produce any neutral currents at all. Take a look on the incoming service panel to see if it says 3-phase, or if there's any 3-pole circuit breakers that's a good hint it's a 3-phase 120/208-volt panel. If it is a 3-phase panel, and you're going to be doing more work in that building, I would ask that an electrician inspect the panel to check the neutral size, and ask him to torque down the lugs on all the incoming phases and neutral/ground wires. These things are almost NEVER checked until something goes wrong and the wires burn up.

RYAN LOUDMUSIC JENKINS:

--- Quote from: Samuel Rees on November 17, 2013, 05:50:23 PM ---128+ Volts registering on a Furman Surge Protector at a venue in working at right now.

--- End quote ---

So what did it measure with you VOM?  I find very little consistency from one furman to another and they rarely match up with my VOMs which always match each other.

Samuel Rees:
I didn't measure it. I was midway through show and I didn't have a meter on me. It was just a walk up. I think this is a sign I need to carry one on walk-ups. It eventually stopped flashing, then went down to about 123-125 by end of show. I've noticed it sits around there before.  I didn't notice any bouncing, but all the gear was up when I observed this. This a 300 cap club, new install (9 weeks) old building. No idea about the panel or anything, I've never looked. Small club vibes so no tie ins or anything. I'll look into it and report it to mgmt. thanks for the insight.

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