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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => AC Power and Grounding => Topic started by: Mike Sokol on January 09, 2014, 01:33:42 PM
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Mike,
I've heard that the typical surge protector will not protect you from a lightning strike because it is too slow to react. By the time the surge protector trips, the lightning has done its damage.
Is that true?
Thanks
I do have one actual example of this. I had a cheap $10 surge strip on my freezer downstairs, and right after a lightning storm we noticed the freezer was dead/off. Lightning had hit the ground across the street perhaps 100 yards away, so I was pretty sure it had smoked the freezer compressor. But doing a little looking I found that the circuit breaker on the surge strip had tripped. Resetting the surge strip's circuit breaker caused it to instantly trip, so I opened it up for a look inside. The two MOV devices inside the strip had burned spots in their centers and turned out to be dead shorted. Swapping out for a new/cheap surge strip got the freezer up and running, and it's been fine for the following 10 years.
Modern sound gear has regulated power supplies and internal voltage regulation and have a lot of spike protection built-in. So while I don't think that cheap surge strips are all that necessary for most distributed live sound gear, they can protect stand-alone gear from nearby lightning spikes in some instances. But this is an interesting jump-off point for a new thread on spike/surge protectors such as Surge-X, so let's jump...
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I do have one actual example of this. I had a cheap $10 surge strip on my freezer downstairs, and right after a lightning storm we noticed the freezer was dead/off. Lightning had hit the ground across the street perhaps 100 yards away, so I was pretty sure it had smoked the freezer compressor. But doing a little looking I found that the circuit breaker on the surge strip had tripped. Resetting the surge strip's circuit breaker caused it to instantly trip, so I opened it up for a look inside. The two MOV devices inside the strip had burned spots in their centers and turned out to be dead shorted. Swapping out for a new/cheap surge strip got the freezer up and running, and it's been fine for the following 10 years.
Modern sound gear has regulated power supplies and internal voltage regulation and have a lot of spike protection built-in. So while I don't think that cheap surge strips are all that necessary for most distributed live sound gear, they can protect stand-alone gear from nearby lightning spikes in some instances. But this is an interesting jump-off point for a new thread on spike/surge protectors such as Surge-X, so let's jump...
As you mentioned, not all lightning strikes are the same - distance between the actual strike location and the gear, impedance of ground/whatever between the strike and the gear, whether the lighting hit some piece of electrical distribution gear - all make a difference in what happens.
Surgex publishes some numbers from strike research in their knowledge base:
http://www.surgex.com/importance.html
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Surgex publishes some numbers from strike research in their knowledge base:
http://www.surgex.com/importance.html
This is a good intro article, but we need real data and diagrams. I'm going to ask Surge-X to supply us with a few white papers to digest.
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On installed sound, how effective are standard snap switches at isolating the equipment from the power lines? I realize that doesn't help when in use, but I have used that in situations where a system is only used a small percentage of the week. Is that a false sense of security?
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On installed sound, how effective are standard snap switches at isolating the equipment from the power lines? I realize that doesn't help when in use, but I have used that in situations where a system is only used a small percentage of the week. Is that a false sense of security?
As the switch only disconnects the hot, that still leaves neutral and ground for the lightning to enter the gear.
I do believe lightning is color blind. Often, it doesn't even need a wire to damage something........
The only effective disconnect is to unplug.
I remember at my grandparents Summer House / Retirement Home, they unplugged everything when they wern't actually on-site. This was after a thunderstorm took out a TV and a couple of radios.
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I have seen were the lightning did not trip the breakers in the home but the Stove electric heating elements all had to be replaced but not the switches. The Fridge defrost coil on the back was burnt to a crisp. All the light bulbs in the house were burnt. We took the lighting strike at the transformer on the pole outside the house.
During the next week after getting the stove and fridge back up we had all the breakers in the panel changed to ensure that they were not arc welded.
The well pump and sump pump was tested Ok, and the furnace and hotwater heating pumps tested Ok. Clothes washer and Dryer I don't remember changing.
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Turned off at the wall is still pretty good protection. Not foolproof against all nearby strikes, but probably 20x less risky than left switched on.
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Turned off at the wall is still pretty good protection. Not foolproof against all nearby strikes, but probably 20x less risky than left switched on.
It's like chicken soup - it may not help but it sure won't hurt.