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Author Topic: 128+ Volts registering on a Furman Surge Protector  (Read 7632 times)

Samuel Rees

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128+ Volts registering on a Furman Surge Protector
« on: November 17, 2013, 05:50:23 pm »

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?
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John Roberts {JR}

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Re: 128+ Volts registering on a Furman Surge Protector
« Reply #1 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
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Mike Sokol

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Re: 128+ Volts registering on a Furman Surge Protector
« Reply #2 on: November 17, 2013, 06:31:55 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
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.
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RYAN LOUDMUSIC JENKINS

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Re: 128+ Volts registering on a Furman Surge Protector
« Reply #3 on: November 17, 2013, 10:13:59 pm »

128+ Volts registering on a Furman Surge Protector at a venue in working at right now.

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.
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Samuel Rees

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Re: 128+ Volts registering on a Furman Surge Protector
« Reply #4 on: November 17, 2013, 11:00:21 pm »

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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Jamin Lynch

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Re: 128+ Volts registering on a Furman Surge Protector
« Reply #5 on: November 20, 2013, 02:57:18 pm »

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.

How would you fix that when in the middle of a show?
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John Roberts {JR}

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Re: 128+ Volts registering on a Furman Surge Protector
« Reply #6 on: November 20, 2013, 04:59:12 pm »

How would you fix that when in the middle of a show?

If your gear is at risk, shut it down.

Call the electrician or whomever is responsible for the power.

Not a user serviceable part.

JR
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Samuel Rees

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Re: 128+ Volts registering on a Furman Surge Protector
« Reply #7 on: November 20, 2013, 06:09:02 pm »

None of it was my gear. The stuff directly plugged into that strip had universal PSUs. Big show for club, I couldn't very well suggest we shut down the show based on 1 Furman. Clearly checking other circuits and etc with my own meter would have helped this issue. From what I understand it's stayed at 120-125 since. Will meter everything on my next show. Any dangers from overvoltage below 240v that I should be aware of, besides damaging gear?
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Brian Bolly

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Re: 128+ Volts registering on a Furman Surge Protector
« Reply #8 on: November 20, 2013, 06:12:16 pm »

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?

Furmans (and many other of the power strip + rack voltage meter devices) have an adjustable pot under the hood to "calibrate" the meter.  That said, I've had more than one Furman or similar device have the meter become "de-calibrated" over time due to failing components in the meter circuit.

In your case, since the install is only a few weeks old I'd check it with an external meter first just to see what's up.
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Samuel Rees

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Re: 128+ Volts registering on a Furman Surge Protector
« Reply #9 on: November 20, 2013, 06:18:21 pm »

Will do. Even if calibrated badly, there was a 5-10+ voltage swing. Weird. I'll post back!
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Mike Sokol

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Re: 128+ Volts registering on a Furman Surge Protector
« Reply #10 on: November 20, 2013, 06:46:24 pm »

Will do. Even if calibrated badly, there was a 5-10+ voltage swing. Weird. I'll post back!
I'm betting on a loose or undersized neutral. Get a licensed electrician to meter between the hot leg and the neutral while putting a load on the opposite hot leg. Lighting or electric heaters would do it. If the voltage moves up by more than a few volts when the opposite leg is loaded, then that's the neutral being dragged around. Of course, he can read the neutral wire size right from the wire insulation. Also have him tighten down all the bus lugs while he's in the box.

Please don't do this yourself since you don't want the liability if something goes wrong, since if not done correctly and something shorts out you can create an arc flash condition which would burn your face off (I'm not kidding). An arc flash is a rather large fireball of burning copper plasma hotter than the surface of the sun traveling at you faster than the speed of sound. You don't want to be in front of one of those when they go BANG.

Mike Sokol
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Jonathan Johnson

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Re: 128+ Volts registering on a Furman Surge Protector
« Reply #11 on: November 20, 2013, 07:03:00 pm »

None of it was my gear.

As a contractor hired to perform services, it is expected that you will use your expertise to provide those services in a competent and safe manner. When unsafe conditions are present, you cannot fulfill that expectation. (Doing anything in an unsafe manner is a hallmark of incompetency.)

Your due diligence in this situation is to inform the responsible party (operator of the venue, the owner of the equipment, the promoter, etc.):
  • Your observations (overvoltage, undervoltage, incorrect or unsafe wiring, etc.)
  • The potential impact of the condition (equipment damage, personal injury, etc.)
  • Suggested corrective measures ("contact a licensed electrician")
  • Actions you will and will not take ("I'm not touching this" or "I'm not connecting my equipment until corrected")
  • Limitation of your liability ("I'm not qualified to rectify the problem" or "don't blame me when the lead guitarist gets electrocuted")
As this is a potentially dangerous situation, this should all be documented in writing with date, time, and location of observations. The responsible party should sign acknowledgement of receipt. (This doesn't imply responsibility, but only as proof they were informed.)

Should the worst-case scenario happen, being able to present documentation created at the time of observation carries a lot of weight in investigations and litigation.
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ProSoundWeb Community

Re: 128+ Volts registering on a Furman Surge Protector
« Reply #11 on: November 20, 2013, 07:03:00 pm »


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