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Old 05-01-2011, 22:49   #1
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Why Not Use UPS for Lightning Protection ?

Having followed a number of threads (and read some articles) on the issue of lightening damaging electronics, I recalled an incident a few years back.

I was in a shared office building when lightening hit the transformer feeding the building. Uninterrupted Power Supplies (UPS) were certainly known, but as our area did not suffer from brown outs, many in the building did not have them.

Me being anal about my computer equipment did.

The building went black, I heard a whole bunch of "Oh Sh*ts", the phones went dead, and the end result was thousands of dollars of electronics was zapped.

But not mine. I actually finished my spreadsheet, saved it, and then turned off my computer.

Why would a USP in front of electronic equipment not work for a sail boat?

Any thoughts?
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Old 05-01-2011, 23:40   #2
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In the case of your building the strike was indirect, lighning hit outside the building, I opine that most of the energy found its way to ground via a different path and what went thru your electrical system was a surge of modest to large proportions, only a tiny fraction went thru your building.

As I understand it there are 2 ways lighning can damage electronics. One is by directly forcing excessive voltage or current thru an item when the lightning strikes the item or something it is electrically connected to.

The second way is by inducing a current in the item. Any electrical current creates a magnetic field around it, a varying current creates a varying field. Any varying magnetic field creates an electrical current in adjacent conductors. A power transformer uses this phenomenon to change the voltage of AC current from transmission voltages to home use voltages, by adjusting the relative lengths of the adjacent conductors the voltage change can be controlled. With a lightning strike the current and voltages in the strike are so high that electricity will be induced in almost any nearby conductor, down to printed circuits on a circuit board on possible even the circuits on chips depending on how close the strike it.

On a sailboat the issue revolves around how close the lightning strike is. If the boat is directly hit current will blow right thru any surge protection in a UPS. If the strike it right next to the boat the current will be induced in the item itself regardless of what, if anthing it is connected to. At a distance the strike needs a longer conductor such at a radio antennae or a power lead from the battery for enough damaging current to be induced, in this case the UPS would provide variable protection related to strike distance, conductors connected to the item thru the UPS, UPS surge protection capabilities and other things it is too late to think of right now.

My feeling is that UPS/surge protection would be of some use, but the best procedure is to stick as much electronic equipement as practical in a metal box, such as the oven, whenever lightning is seen nearby or when you leave the vessel for longer than the most current forecast.

As long as the equipement is not connected to the outside (disconnect power and antennea) any current induced by a nearby strike will be in the metal shell of the oven (assuming a metal door with no window). The oven or metal box acts as a Faraday cage.

If I had a lot of equipement aboard that made disconnection on a regular basis impractical, I would certainly use the UPS/surge protection as a way to improve the odds.
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Old 06-01-2011, 01:10   #3
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Electrically a ups/ surge protection is allmost useless on a boat. You simply don't have a ground path to handle it. Secondly the lightening going to fry all that stuff anyway, completely, utterly.

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Old 06-01-2011, 09:15   #4
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Electrically a ups/ surge protection is allmost useless on a boat. You simply don't have a ground path to handle it. Secondly the lightening going to fry all that stuff anyway, completely, utterly.

Dave.
Are you suggesting that is because of the induction issue that Adelie talked about?

The transformer I mentioned that got hit, BTW, was only 25 feet away from my office, so would there not have been some induction from it?
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Old 06-01-2011, 09:45   #5
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Originally Posted by avb3 View Post
Are you suggesting that is because of the induction issue that Adelie talked about?

The transformer I mentioned that got hit, BTW, was only 25 feet away from my office, so would there not have been some induction from it?

Where can lightnening strike your boat and be more than 25ft away???
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Old 06-01-2011, 10:11   #6
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Where can lightnening strike your boat and be more than 25ft away???
Capn Bill, what I was trying to say that it hit very close, but I recognize that there are differences.

I am not an electrical expert by any means, but it did occur to me that if one can isolate the charge, it may help. I know I can and have protected electronic equipment in the past with a UPS, and the thought occurred this may be cheap insurance.

It may also not work, I just don't know.
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Old 06-01-2011, 10:27   #7
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Where can lightnening strike your boat and be more than 25ft away???
I don't want to get hung up in a semantic battle but the top of the main mast is 45 feet off the deck.

However, last fall we had a near-miss/near-hit from a lightning strike.

5:30 in the morning we were awakened by a small sudden thunderstorm. <Flash-crash> we both said to each other, "Well, that was close."

Over the next two weeks we discovered some things that no longer worked. When I tested the radar it worked for about 1 minute before the CRT gave it up. There were odd things like the GPS worked, but could no longer port data out to the computer. A variable speed fan quit. Etc. etc....mostly everything electronic that has a presence in the vicinity of the mizzen was affected.

Two days later a boat 100 meters away had a direct hit. Lost everything electrical. He couldn't even start his motor afterward. It fried his starter.
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Old 06-01-2011, 12:35   #8
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avb, a UPS doesn't protect you from anything except power failure. Most UPSes also have SURGE PROTECTORS built in, and the simple surge protector, which can be a 50c component, is what protects you from power surges. from 50c to ten bucks, depending on whether you buy a tranzorb or zener diode, or a polyphaser. They all have rated limits, for how large a surge they can stop, and how many surges it will take to wear them out.

So if you want to protect electronics, look at lightning protection, surge protection, ground schemes...but save your money on UPSes. Use them to keep things running during blackouts and brownouts, not as protection from zaps.
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Old 06-01-2011, 12:54   #9
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I don't want to get hung up in a semantic battle but the top of the main mast is 45 feet off the deck. WADDA
(it is not where the lightening touches, it's where it goes down every conductive surface.)

In a building a UPS, (full isolation type), does give some measure of lightening protection beyond that of a "surge suppressor". Not only do most UPS's contain a thyrister or other surge suppression device, but the "FULL UPS", not the cheaper standby types, work by charging a battery then using the battery to power an inverter to reconstruct the AC. This provides complete protection from any surges coming down the line, as the inverter will not reproduce any except normal voltage, an internal inductor also levels the voltage. Any spike big enough to get through the UPS will most likely blow a fuse IN the UPS preventing spikes coming from the incoming power from reaching the equipment. IN a sail boat unless you are plugged into a dock, you are already generating your own power and thus already have as much of this protection as you can get. If you are asking will a UPS give additional protection if lightening hits a power line at the marina, YES it will. If you are asking will it/can it protect if lightening hits your mast and conducts into your engine room, and electrical panel, Sadly NO.
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Old 09-01-2011, 10:45   #10
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One other way that lightning fries your equipment is by elevating the electrical ground level (in the case of nearby strikes). That can cause a reverse electrical current and non of the UPS or surge protectors take care of that situation.

The only way to truly protect a piece of equipment is to disconnect it.
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Old 09-01-2011, 11:09   #11
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What about lightning rods?

I have been told that they reduce the probability of a direct hit by draining charge from the atmosphere around them prior to any strike happening. The result being that any strike would occur further from the boat, or may be averted.

Also, is there any data on the electromagnetic pulse of lightning affecting marine electronics? I have not experienced damage to mine due to lightning, although I was near a cell that caused me to move away from it. I either was simply not affected by the nearby strikes from that cell or my lightning rod actually helped.
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Old 09-01-2011, 11:38   #12
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What about lightning rods?

I have been told that they reduce the probability of a direct hit by draining charge from the atmosphere around them prior to any strike happening. The result being that any strike would occur further from the boat, or may be averted ...
Lightning rod systems (rod/air terminal, downconductor, & gnd electrode) are not intended to (and don’t) reduced the likelihood of receiving a strike.
They are intended to mitigate the damage a strike causes, by providing an intended path to ground.

The charge dissipation myth has no basis in fact.
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Old 09-01-2011, 12:05   #13
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Gord,

Your knowledge is amazing, and up to date. My previous information is more than thirty years old.

Here is what i just found at Wikipedia about lightning dissipation:
Lightning dissipation

Lightning dissipators have been widely discredited and criticized by lightning researchers over the last 30 years. These terminals (known as Dissipation Array Systems, and Charge Transfer Systems) claim to make a structure less attractive to lightning and other charges that flow through the Earth's atmosphere around it. These generally encompass systems and equipment for the preventative protection of objects located on the surface of the earth from the effects of atmospherics. The devices are alleged to deal with the phenomena such as electrostatic fields, electromagnetic fields, field transients, static charges, and any other related atmospheric electricity phenomena.
Individual dissipator rods may appear as slightly-blunted metal spikes sticking out in all directions from a metal conductor.[22] These elements are mounted on short metal arms at the top of a radio antenna or tower, the area most likely to be struck. The dissipation theory states an alteration in the potential difference (voltage) between the structure and the storm cloud miles above theoretically reduces but does not eliminate risk of lightning strikes.[23] Various manufacturers make these claims. Induced upward lightning strikes occurring on tall structures (effective heights of 300 m or more) can be reduced by altering the shape of the structure.[24]
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Old 10-01-2011, 06:58   #14
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One other way that lightning fries your equipment is by elevating the electrical ground level (in the case of nearby strikes). That can cause a reverse electrical current and non of the UPS or surge protectors take care of that situation.

The only way to truly protect a piece of equipment is to disconnect it.
Correct, This is exactly what i Meant when I said that you dont have the " ground system" to protect you from ligthening surges, UPS or not.

Dave
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Old 11-01-2011, 09:52   #15
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Originally Posted by St. Elsewhere View Post
What about lightning rods?

I have been told that they reduce the probability of a direct hit by draining charge from the atmosphere around them prior to any strike happening. The result being that any strike would occur further from the boat, or may be averted.

Also, is there any data on the electromagnetic pulse of lightning affecting marine electronics? I have not experienced damage to mine due to lightning, although I was near a cell that caused me to move away from it. I either was simply not affected by the nearby strikes from that cell or my lightning rod actually helped.
The problem of a lightening rod is that they are to provide a controlled place for lightening to strike to condict to ground. In case of a direct hit NOTHING will protect delicate electronics that have circuits inside sensitive to millivolts, (or at most 5volts). The induced charges from a nearby strike are in the 10's to hundreds of volts, (the tingle you feel from a near strike), are enough to completly kill anything not powered by vacuum tubes. A strike on an electric line can put a spike of thousands of volts that can travel several miles on electric lines before being damped by the power companies lightening arrestors. This is what ALL electrical protections try to stop, (surge suppressors, etc.), with varying degrees of sucess. Older electronics feed incoming power through a big heavy transformer that stops most of these surges. Newer electronics feed incoming power directly into an IC chip that regulates and converts the power to DC, (and sometimes provides most of the functions of the device).

The original question is would a UPS provide additional lightening protection to AC devices? If you are watching TV plugged into a marina during a lightening storm in a nearby city, YES. If you are at sea, NO. If it hits anywhere near your boat, nothing will, (except putting all electronics powered off in a faraday cage, (I.E. unplugged microwave oven, wrapped in metal foil, etc...), The TV already has a lot of shielding inside because of the RF, so if unplugged should be fine.
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