DAY 3 Lightening conductor

[7029 dave]

Another snap taken in Poland of a castle, the lightening conductor up the building (crude at that), you can see that they have bonded the iron window bars off it as well. I know this is a specialist area my knowledge is zero, your thoughts please.

 

[davesparks]

Bonding of external metalwork to the LPS is required for effective protection.

The fixing via and eyebolt and clamp makes me think the conductor is tensioned between there and a point at the top of the building like a catenary to avoid having to put a lot of fixings into the walls.

 

[oscar21]

Bit of trivia I'm sure most experienced sparks know but a lightning conductor doesn't attract lightning and guide it to earth but instead bleeds off enough electrons from the sky so there is never enough of them to form into lightning in the first place.

 

[James]

erm, not convinced on that one.

 

[DPG]

The sky has far too many electrons anyway. I often remove some excess ones.

 

[Simon47]

erm, not convinced on that one.

It's true.
Prior to a lightning strike, a charge is buikt uo between the earth and clouds - very much like charging a capacitor. Wgen the field strength gets high enough, a discharge starts, the air alobg that discharge ionises, and then the full lightning strike happens. Midern high speed video has shown that the strike starts with a small leader from the ground (or a structure) heading upwards and creating the ionised channel - then the full strike travels down that channel.
The tips of the rods are normally pointed. This creates a concentration of field strength around the point, that then creates a corona and draws out charge from the air in the vicinity of the rod.
Remember that you don't need to discharge a large area - the idea is to avoid the strike hitting your building, so you just need to clear enough area to send the lightning somewhere else.
Only if this fails does the LPS (lightning protection ststem) do what peopke think it's there for - divert the lightning strike current away from the building structure.