We’re designing a kiosk to be used by the city at various outdoor events this summer. It’ll have a 2″ aluminum tube frame, and (3) stations with touch-screen monitors and cpu’s. The tube frame will be covered in stained veneer plywood and polycarbonate panels, but portions of it will be exposed. The whole thing is meant to invite citizens to provide comments on city functions and needs, as they perceive it.
Someone’s questioned whether this will be susceptible to lightning, and if there’s a way of grounding the whole kiosk. It’s going to be mounted on (6) industrial casters, but it’s movable and will be in different locations. Is there a way to ground something like this? My thoughts are it will be surrounded by tents, displays, outdoor cooking stands, etc., which all have metal frames. I don’t know that this kiosk will be any more susceptible than anything else. And if lightning hits it, there will be little to shield the computer equipment, regardless of grounding.
Any good ideas?
Replies
Other than ensuring the outlet you are plugged into is grounded, I think you have nothing else you could really do.
Rebuilding my home in Cypress, CA
Also a CRX fanatic!
Parenting has always been a mix of sage life advice and inexcusable laziness.
There are lightning protection systems out there, which consist of copper terminals at the top of the structure, wired down to a large grounding field or array of grounding rods. In fact, I think a lot of farmhouses in the midwest had similar lightning protection systems.
Whether or not it would do much good on this type of structure, or if it is worth the expense, I don't know. You might want to talk to someone who designs those systems, and get a quote, or an idea of what they would recommend. It doesn't seem like there is going to be anything that will be cost effective in protecting 3 computers, especially if grounding sysems need to be at several locations.
zak
"When we build, let us think that we build forever. Let it not be for present delight nor for present use alone." --John Ruskin
"so it goes"
I don't think there is anything you can do. If lightning got close enough to hit any kind of ground rod, its probably going to overwhelm anything thats inside the kiosk.
You get out of life what you put into it......minus taxes.
Marv
The voltage and currents from a direct lightning strike will probably vaporize any grounding arrangement that involved wires in an extension cord. You could build a Faraday cage -- a structure completely enclosed on six sides made from metal sheets -- and that might offer some protection. Short of that I'd say the best bet is to get inside a building or car when lightning is in the area.
It would help a little if the aluminum frame were grounded via a hefty cable to a ground rod as close as possible. If you're set up on a lawn then you'd drive the rod right in the back corner of the unit, keeping the ground wire to about 8" probably. Other places you could maybe clamp to a pipe.
If you have to go farther than about 15 feet to the ground then there's little advantage in grounding the frame, though.
Even without grounding, the frame offers some very slight protection from lightning, possibly enough to save humans, but not enough to protect equipment.
Do make sure that the equipment is all plugged into a common plugstrip, with a heavy cord (#12 or #10) and no "doctoring" of the ground pin on the plug or anything further downstream.
Yeah, i thought of the pipe connection too. Also considered connecting to a nearby light pole, but thought the height would attract lightning and negate any grounding effect. The grounding rod option probably won't be applicable most of the time, since this will be located primarily on asphalt/concrete. Thanks for all the answers everybody. Everything was pretty much what i imagined. This was one of those 'cya' questions brought up at the last minute, and seemed to take on a life of its own.my official answer will be . . . bring hot dogs :)
Edited 5/31/2007 10:05 am ET by draftguy
Yeah, build a giant version of one of those old "Hot Doggers" and wait for the lightning to strike.
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
Kiosk = 8'-10' tall
Tent = 10'-20' tall
Tent = lightning protection for kiosk.
(|;>)
Seriously, the only protection worth it in that situation is a good insurance policy.
SamT
Praise the Corporation, for the Corporations' highest concern is the well being of the public.
perhaps you can contact a a boat dealer, maybe one that sells lots of sailboats ..... ..they should be able to provide some details
but like others have said it will cost more than the kiosk
anyway, I'm pretty sure that EVERY joint would require a jumper of substantial size
at least a 4/0 bare braided wire, plus a tall spike on the top .
scale your kiosk on paper, then draw a right angle whose sides will just touch the top of the sides of the kiosk similar to a pyramid..this could be the height of the spike above your hut then you need to run the BIG wire down..weld it or use appropriate clamps to every jumper inside forming a "cage and run OUT to the four points where the angles contact the ground and then connected to ground rods ....ALL the way around your kiosk
IOW at each corner
I never designed the layouts.
.only installed them over the years.so this is all just a WAG
But who is going to be in there during a thunderstorm ?
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, wer ist jetzt der Idiot ?
Based on the logic that better ground paths are the "preferred" route for lightning, seems like grounding the kiosk would make it more vulnerable to strikes, not less.
Would not make it significantly more likely to be struck, but would increase (slightly) the safety of occupants during a strike.
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin