it does every day on microwave and cell towers which i work on.
skyscrapers in large cities (like NY) take lightning hits all the time and nothing in the building is destroyed. you can even find videos of the strikes hitting the electrodes on the top of the building
I've been in electrical closets in one of those skyscraper's power risers. The grounding cables were impressive! My understanding is this is partly for lightning protection, but also as a ground reference for the broadcast antennas.
I don't think any amount of bonding/grounding will protect from a close lighting strike.
I'll disagree. Look into IEC 62305. Lightning protection systems to prevent structural damage were well documented by Benjamin Franklin. UL 96 and NFPA 780 codify this knowledge today. IEC has taken it to the next level, showing how to protect modern electronics from
direct strikes.
Suffice it to say (from what I can shoehorn into a single post) that with an air terminal network and down-leads to take the brunt of the direct strike energy and with proper structural bonding to prevent flashover, off the shelf SPD/TVSS can and does protect your electronics within the protected envelope of those air terminals. This also means that the same SPD will protect against nearby strikes.
The biggest risk is when lightning directly strikes your equipment bypassing your LPS downleads. UL 96 terminal heights and spacing are based around an assumption of a 150' rolling sphere. For those not familiar with the concept, I'll put it this way. Current code for the spacing between railing balusters is that they must be tight enough to prevent a 4" diameter ball from passing between them. That's to prevent a child's head from fitting between balusters. Well with lightning, we make the assumption that it takes the form of a sphere 150' in radius. Rest that hypothetical sphere on your terminals, or roll it on the ground up to them, and anything under it that cannot be reached by the sphere is protected by those terminals.
What's interesting is where that sphere visualization was derived. Lightning (for the most part), travels down from the sky as a stepped leader until it's close to the ground, where an arc will be initiated from the ground up to meet it (the streamer). The distance the streamer will travel from the ground depends directly on the strike energy. Based on data collected in the field, around 90% of all strikes are 10kA or higher in peak current, and those 10kA strikes have streamers around 150' in length. And that's where the 150' rolling sphere came from.
The interesting part is that higher strike peak currents come with longer streamers, which means that the protected area is LARGER. At the extreme end, a 200kA strike has a streamer of over 1000', so you could visualize the protection of an air terminal using a 1000' rolling sphere, and the area under its canopy is immense.
3kA strikes make up about 1% of lightning strikes, but they only have 65' streamers, so they can reach into tighter spaces.
Which goes to show that lightning and intuition just don't go hand in hand.
Nothing you can afford, anyway.
I wouldn't say that. Lightning protection system costs are directly related to the structure height. I've seen stuff small enough to protect a single historic tree, and it's anything but spectacular. Woven aluminum "Class 1" downlead for buildings under 75' in height is 10.5mm in diameter, which makes it comparable to 3/0 wire. The woven stuff lays more easily and weighs less, but 3/0 should be no worse otherwise, and that's well under $2/foot.
