[Elecraft] A dumb question about lightning

[jerry]

Interesting.  Suppose the service entrance is at one end of the house,
and the ham shack at the other end?  I don't think it's physically
possible to provide a low inductance path that's 60 feet long, is it?

    Would a solution be to DC-isolate the station from the grounded 
antenna?
Say with a wideband toroid 1:1 transformer?  Then ground the station 
through the
3rd pin of the AC outlet?

    Here in the San Francisco Bay Area, lighting is rare.  It used to be 
entirely
unheard of - we just don't get the kind of convective weather that 
produces it. We're more about coastal stratus.  But with climate change, 
that might be changing.  There was quite a display once last year.

             - Jerry, KF6VB


On 2023-07-31 13:20, Fred Jensen wrote:
> Be very careful of advice regarding lightning protection.  There are
> some very good sources, starting with the NEC and including material
> from ARRL.  Some is somewhat non-intuitive.  For example, the NEC
> requires that any additional "earth electrodes" [aka ground rods] be
> bonded to the service entrance earth electrode with a low inductance
> path. There's been quite an array of advice circulating here recently,
> much of it wrong, some dangerous.
> 
> 73,
> 
> Fred ["Skip"] K6DGW
> Sparks NV DM09dn
> Washoe County
> 
> Geoffrey Feldman wrote on 7/28/2023 5:02 PM:
>>   First thing and foremost - switches are mostly not relevant to 
>> protection.
>> Energy that can travel 1000' through the sky is likely to continue 
>> across
>> most switches.   So, the utmost of safety is what you indicated you 
>> did -
>> disconnect.  By disconnect, I mean either disconnect outside the 
>> building,
>> leaving the feed on the ground or leave the feed connected to a copper 
>> plate
>> that is in turn connected to an 8' deep ground stake.  On the inside 
>> of the
>> house, disconnect the lines from that plate and leave them on the 
>> floor.
>> Another such stake near the feed point of the antenna is also a great 
>> idea.
>> If it's possible to lower the antenna when not in use, that's a great 
>> idea.
>> This should be the default when not in use.
>> 
>>   You have the belief that no grounding system is perfectly effective 
>> (for all
>> imaginable strikes) - maybe, but a good grounding system is far better 
>> than
>> foolishness.   A grounding system, or an antenna is not a "lightning
>> magnet". If it doesn't strike it won't. If it does it will and the 
>> grounding
>> system assures the energy will be less likely to cause harm. Some 
>> places and
>> circumstances are more or less likely but everywhere is possible.   If 
>> that
>> possibility happens, a good grounding system is why it is likely to be
>> survived.
>> 
>>   A key thing to understand is that when Lightning strikes in nature, 
>> all the
>> energy travels along the surface of the ground.  It can do this for 
>> many
>> feet and be lethal doing it.  Anything that stands along the radius 
>> from the
>> point of the strike (one part closer and the other further) is in 
>> danger.
>> Four legged animals, having more distant contact points, more 
>> dangerous.
>> The purpose of a ground stake (8' straight down) is to channel the
>> electricity deep, rather than along the surface.
>> 
>>   Don't use emotional theories.  Read the lightning mitigation and 
>> grounding
>> books offered by the ARRL. Use UL approved conductors and stakes.  Do 
>> not
>> use your homes electrical service ground stake. Keep that separate.
>> 
>>   All the above is a "cliffs notes" and so is anything else posted 
>> here. Read
>> the books.  Ask senior members of a local club,  to review your plan.
>> 
>>   W1GCF Geoff
>>