Would steel post to support string lights on a deck attract lightning?

[hanklazard]

A customer wants to install string lights on their deck. I suggested 1 steel post attatched to wood deck to reduce sagging and they're concerned 1 8 foot metal post attatched to wood would draw lightning. I couldn't think of a good reason why this would be case or cause this but also didn't have a great explanation on why it wouldn't be an issue. My concern is most pine posts might start to bend or sway in a few years and be less rigid. Any suggestions? I haven't found any suitably strong fiberglass poles yet. I only ever consider this when installing large parking 30-40 feet lot lights and we've started opting for fiberglass poles due to how light they are and lack of conductivity.

 

[brantmacga]

Steel or aluminum poles are pretty standard for festoon lighting on commercial projects and there are no special considerations for lightning on anything I’ve been involved with.


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[hanklazard]

Thanks, that's what I've used before but I also never had a customer ask about lightning before.

 

[tom baker]

Point out the house is full of copper lightning attracting wiring. I was going to suggest a ground road at each steel post, but will not.

 

[jmellc]

Not worth arguing with customer. Get the sturdiest treated wood post you can find. A round one may resist warping better than a square one. Not totally sure on that.

 

[winnie]

I think post 5 is the practical answer. This is a no win argument to have. Go with whatever the customer wants for aesthetics.

As far as an answer to have if the question comes up again: a pole _will_ attract lightning if it is already close enough. But 'close enough' is a very short distance.

Look up the 'rolling sphere model' to get an understanding of how close is relevant. A 10 foot high pole in the middle of a perfectly flat field might attract strikes which would otherwise fall up to 50 feet away. Any other objects in that small circle might act to shadow the pole.

If there is already a strike going to happen to the area of the deck, the wet wood pole is probably as good as a metal pole for the final redirection of the strike.

If lightning strikes the pole, a metal pole might survive.

Jon

 

[Frank DuVal]

Wait, are you attaching wire to the tops of these poles? If so, they already created the lightning target!

Best to tell the customer to scrap any of these lighting plans if lightning is the worry! So the pole does not matter. In fact the metal pole, if grounded, would help negate the lightning pulse from entering the building along the lighting wire.

Point out the house is full of copper lightning attracting wiring.

Yep, so is the lighting wire they want to string up.

 

[ggunn]

Not worth arguing with customer. Get the sturdiest treated wood post you can find. A round one may resist warping better than a square one. Not totally sure on that.

I used 2X2 square poles to support mine; they have been in place for two or three years. Most of them are still straight, but one of them is bent a couple of degrees in the direction of the pull from the lights. This spring I will turn it around.

 

[steve66]

I was actually thinking about trying to string some lights from a PVC pipe. Maybe 2"?

 

[jaggedben]

The material of the pole makes essentially no difference to whether lightning will strike it. Potential difference between points is not affected by resistance of material before current flows.