Protecting 1Gb Ethernet From Lightning Strikes

Wed Aug 14 17:54:47 UTC 2019

This. Very little will protect you from a direct strike.

Working for a WISP for a long time as a past life, I've seen radios
physically split in half. Chunks of concrete taken out of walls near the
equipment. Black ethernet ports that have functionally soldered themselves
into the jack. Six figures worth of lost gear over the years (Does sound
like much, But at ~$80 a pop for cheap wisp gear. That's a lot of
equipment.)

Outside of a direct strike, You can still melt gear left and right. The fix
is no one solution, But multiple.
1. Shielded Ethernet with proper shielded and bonded ends.
2. Proper Grounding
3. Ethernet Surge Suppressors.
4. Proper Grounding.
5. Proper Grounding.

The key is to make your sensitive electronic equipment a higher resistance
path instead of your grounding system. You're going to get inductance build
up on cables you just have to get it to ground through something that isn't
your site switch/router. And it's going to get there one way or another.
Sometimes this can be harder then one might think. Even considering sinking
your own ground rod, And replacing it every few years. As a ground rod
becomes less and less effective with every strike (Depending on what it's
sunk in). Ethernet Surge Suppressors CAN help. But only in assisting in
getting whatever was already on the cable to ground.

And don't forget ground potential differences between different grounding
systems.

Doing the above will get you through most near by strikes. But all bets are
off on direct strikes. The above can also help you with a ton of other
interference. Like a giant FM transmitter running at 100KW a stones throw
away from your equipment but that's another story for another thread.

On Wed, Aug 14, 2019 at 1:34 PM Chris Knipe <savage at savage.za.org> wrote:

> Think surge protectors will protect against strikes that is far away, and
> the residual surge it creates.
>
> A direct strike?  Don't think there's anything that will really protect
> against that.
>
> On Wed, Aug 14, 2019 at 7:29 PM <bzs at theworld.com> wrote:
>
>>
>> Are "surge protectors" really of much use against lightning? I suspect
>> not, other than minor inductions tho perhaps some are specially
>> designed for lightning. I wouldn't assume, I'd want to see the word
>> "lightning" in the specs.
>>
>> I once had a lightning strike (at Harvard Chemistry), probably just an
>> induction on a wire some idiot had strung between building roofs (I
>> didn't even know it existed) and the board it was attached to's solder
>> was melted and burned, impressive! More impressive was the board
>> mostly worked, it was just doing some weird things which led me to
>> inspect it...oops.
>>
>> My understanding was that the only real protection is an "air gap",
>> which a piece of fiber will provide in essence, and even that better
>> be designed for lightning as it can leap small gaps.
>>
>> Check your insurance, including the deductibles, keep spares on hand.
>>
>> P.S. My grandmother would tell a story about how what sounded like the
>> ever-controversial "ball lightning" came into her home when she was
>> young. Good luck with that!
>>
>>   https://en.wikipedia.org/wiki/Ball_lightning
>>
>> --
>>         -Barry Shein
>>
>> Software Tool & Die    | bzs at TheWorld.com             |
>> http://www.TheWorld.com
>> Purveyors to the Trade | Voice: +1 617-STD-WRLD       | 800-THE-WRLD
>> The World: Since 1989  | A Public Information Utility | *oo*
>>
>
>
> --
>
> Regards,
> Chris Knipe
>
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