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Surge Suppression vrs. Lighting and Power Spikes

OK,

Here is something I have thought about on many occasions while jamming out and then being rudely interrupted by an overhead lightning storm. Should I continue my session while the storm is overhead or should I switch everything off and wait until it blows over before continuing? I have chosen to switch my equipment off but leave it plugged into the wall.

Is powered on audio equipment any more vulnerable then powered off or in standby mode audio equipment during a lightning storm or power grid spike? I mean if your house gets hit by a direct lighting strike that was the result of having an old school TV antenna on your roof or if the power station down the street gets zapped the wave of electricity is coming your way weather you like it or not, correct?

As an example, if we take 3 houses that are all on the same power grid into consideration during said event, does the house who happens to be drawing the most current at the time of the event have a higher likelihood of being the one who gets chosen by the power spike as it's target for discharge? The term magnet comes to mind as another way of thinking about it.

Now I would imagine this spike has the potential of being very powerful. I have seen some numbers on the web stating that a direct lightning strike can generate anywhere from 1000 to 100,000 AMPS of juice. If these numbers are even somewhat close to being accurate then even the fanciest surge protection/power distribution device isn't going to save your equipment.

If your lucky enough to have the direct hit occur at the power station down the road then I assume the power company has some kind of buffer device that absorbs a large portion of this electricity before it reaches your house but this is just an assumption. If they do have some kind of buffer then maybe your surge protection device has a better chance of survival since the impact would be greatly reduced; maybe even to the levels that most surge protectors found in the home can tolerate and maybe not.

It almost seems that the only real safe bet would be to fully unplug your power distribution device from the wall since we obviously can't predict how the power spike will arrive either thu a direct hit or a possible buffered hit.

I'm curious to know what the general consensus is on this topic and what others do when faced with a storm overhead?

Please feel free to post your thoughts..Thanks
eniac26
jea48
4,668 posts
 
Problem with grounding is that it has to be done (to be legal and insured) with at least gauge 10 wire to ground rod with bends of no smaller radius than 6".
06-13-11: Kijanki
Kijanki,

You are correct on the size of the wire. #10 awg copper or #8 AWG AL minimum. NEC 2008 (810.21 (H)) I would never use AL.....

The way I read it if a separate earth grounding electrode is used the grounding electrode, ground rod, shall be connected to the main electrical service grounding electrode system with a bonding jumper no smaller than #6 awg copper or equivalent. (NEC 2008 810.21 (J))

The important thing here is the antenna grounding conductor ends up being connected to the main grounding electrode of the electrical service of the premises, end result.....
Is that the way you understand it?
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kijanki's avatar
kijanki
4,446 posts
 
Jea48 - I'm not sure. I think that if house has already grounding rod they allow to use jumper but if it doesn't then ground rod need to be placed.

There used to be a lot of antennas around (none grounded) replaced last years by cable or satellite. I'm the only one with antenna on the roof now. I like basic programing and am getting it OTA in HD for the last 10 years. I could possibly move to cable but I watch too much TV the way it is. Pretty much like giving drugs to an addict.
jea48
4,668 posts
 
I would bet most residential earth grounding electrodes are inadequate when it comes to lightning protection.

If memory serves me right the maximum electrode to earth resistance of 5 ohms per IEEE.

http://www.cpccorp.com/deep.htm

http://www.erico.com/public/library/fep/LT0359_1.pdf
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kijanki's avatar
kijanki
4,446 posts
 
Jea48 - one of our customers returns heavy current transients of vector drives to building frame. It works much better for them than ground rods they had before, because earth had tendency to be dry and constant watering them was a big hassle. Unfortunately I don't have metal frame and would have to use ground rod hoping that thunderstorm will bring rain first.
hifihvn
943 posts
 
Yes, that is a problem with ground rods alone. Might be it's part of the reason for the bonding to the homes ground too. Plus less chances of arcing over I imagine. I saw that link Jea48 posted and couldn't find it again. Thanks for posting it. Good info. I guess they've learned a lot from those experiments, with shooting those rockets up into the clouds in Florida. A lot of those skyscrapers have some big thick steel plates under them, where it's nice and moist, plus all the contact with the moist ground must be the reason they take all those strikes, without any problems. Still better odds with a wire with a ground rod will direct a lot more toward the ground, instead of coming straight down through the roof I would think. Years back before cable TV, our roof antenna was on a tripod, with a 4 gauge solid copper ground wire,and it still had me moving away from that end of the room below it, just in case, during a nasty storm. Another link to read. [http://www.ece.ufl.edu/announcements/news/2003/lightning-powerlines.html]
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