Grounding a Tin Roof

[skent]

The house is close to 200 years old. Orig was a one floor cabin. Second floor was added in the 1890's.

the tin Roof is close to 70 years old.

I had to put new rain gutters up last weekend, and got to thinking, if the roof were to be hit by lightening, what could happen. There is no real path from the roof to ground, other than thru the house/wiring.

Would it make sense to attach a #2 copper or Alum wire to the corner of the roof and attach to a ground rod?

I don't want to do anything to attract it, but to prevent any damage.

Any advice?

[_RaT_]

That lightning will find a path, after all it just traveled 30,000 feet without one. In all seriousness, I don't see why a ground would hurt, just how effective it would be in the event of a strike is anyones guess.

[EastTexFrank]

I can't see what it would hurt but can't see that it would help either. It would need to be some pretty stout wire to potentially handle a few million volts travelling close to the speed of light. [img]/forums/images/graemlins/crazy.gif[/img] [img]/forums/images/graemlins/crazy.gif[/img] [img]/forums/images/graemlins/crazy.gif[/img] If it really worries you maybe you need some kind of lightning rod, higher than but still close to the house but then again that might just provide a target.

[Inspector507]

Trained lightning protection people are worth their weight in gold. In this area all lightning protection installers must be certified by UL. The conductor they use from the rods to the ground are loose braid, multi-strand copper. I think Aluminum would melt before any benefit could be gained.
My advice would be to have someone trained do the installation for you. Rods along the ridge line AND on the chimneys.

[DaveNay]

For the most part, lightning arrestors do not provide a desireable path to ground for a lightning strike. They are designed to dissipate electric charge from the air around the protected structure, and prevent a lightning strike in the first place. I believe that the electrode is actually insulated from the structure, and does not provide a ground for the structure.

As Inspector507 mentioned, someone who is qualified in this respect is the best answer available.

Dave

[fivestring]

"The conductor they use from the rods to the ground are loose braid, multi-strand copper. I think Aluminum would melt before any benefit could be gained."

With the amount of volts, amps, watts in lightning, nothing man knows of will hold up to a strike, including multi-strand copper.

[DaveNay]

</font><font color="blue" class="small">( With the amount of volts, amps, watts in lightning, nothing man knows of will hold up to a strike, including multi-strand copper.)</font>

WHAAATTTT?!?!?!

[img]/forums/images/graemlins/confused.gif[/img] [img]/forums/images/graemlins/confused.gif[/img] [img]/forums/images/graemlins/confused.gif[/img]

You mean the little $2 "lightning trap" thingy I installed on my telephone line won't work???

[img]/forums/images/graemlins/shocked.gif[/img] [img]/forums/images/graemlins/shocked.gif[/img] [img]/forums/images/graemlins/shocked.gif[/img]

Dave

[skent]

I found a web site that sells all the stuff

http://www.lightningarrestor.com/

good place to start

[boustany]

Believe it or not, a 'lightening trap' probably will work, because that sort of thing is designed to protect against the very short duration pulse induced by a 'near strike'. For example, if lightening hit a tree, the EMF generated would induce a powerfull voltage in nearby telephone or power lines which would be enough to fry most electronic gizmos. A direct strike will vaporize most any conductor.

I actually saw lightening strike a building about 50 feet away from me at the time. For some reason I was staring at a wall while wating for the rain to stop and lightening hit the part I was staring at.

It was awesome, just like a bomb went off inside the brick wall. A sci-fi death ray wouldn't have been more impressive.

'Thunder is good, thunder is impressive; but it is lightening that does the work' - Mark Twain.

[SPIKER]

Like someone said not much will survive the lightning strike...


The copper conductor usually will be leave a tail tale sign that there was a hit, there should be a fused link in the run near the gorund and that will blow out, and then the lightning will still let current flow, but at a reduced rate as it will use the vaporized copper that is in the air as a current path. quite impressive needless to say!

I was looking out a window durring a storm when I was 16 or so, it struck an old ELM tree about 60 yards out. I went out to take a look the next day. I WISH I had a camera back then. it took the bark off in a spiral candycane type stripes 4 of them one on each quarter. the strips were about 1" wide and 1" deep in the wood/bark. and laied out away from the tree like some one took a giant apple peeler and ran it down each quadrant of the tree and left the bark attached to the base still but the top starting pints fell back about 40 feet out and away form the tree's main trunk!


Anyhow the roof is susposed to be Insulated from the rods that way the lightning goes out around the structure... someone mentioned this above too...

Mark m [img]/forums/images/graemlins/smile.gif[/img]