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We recently put up a put up a gazebo on the deck of our condo unit to provide some much needed shade. The gazebo is 10'x12' and the deck is 12'x16'. The frame is light gauge hollow steel thats powder-coated. The frame slants up from the sides to a small canopy for ventilation. The top is water resistant and flame retardant.

Shortly after putting it up we got some strong thunderstorms and I wondered if this steel frame (comes to a point about 9' high) sitting on a wooden deck would be attractive to lightning? Also I realized that we have a mostly stainless steel grill on casters and attached to a natural gas line that runs out of the basement. The line in some type of heavy rubber or plastic tubing. Don't know if it's flexible metal on the inside. A Gas Co. guy came out and checked and approved the connection, but didn't mention anything about grounding it.

So the question is should either or both be grounded and how should it be done? We do have some tall trees about 15-20' from the deck. Maybe they would be more likely to be struck and i am over-reacting?

Skip K.
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    I have never grounded any of the metal patio covers that were on wood decks. I have grounded metal buildings as required by code for the electrical and never had an issue either way with lightning. I have seen a direct strike on a house and the entire electrical system was destroyed and the house burned. I am not sure how much good a ground would do after seeing the damage a direct strike caused. – Ed Beal Jul 03 '16 at 14:39
  • Considering the gazebo and grill are insulated from the ground, by both the deck, and plastic wheels, in the grill's case, wouldn't them being ungrounded make them less likely to be struck, since they wouldn't complete the circuit from cloud-to-ground? I may be totally off base here. – Gabe Evans Jul 03 '16 at 15:07
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    @GabeEvans If lightning crosses the few thousand feet of air to the clouds, it won't have a problem with the few inches from the structure to the ground. The metal still forms a pathway with greater conductivity. – Hari Jul 02 '18 at 21:44

2 Answers2

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If lighting hits an ungrounded metal structure, it will usually branch out at the bottom of the structure, following multiple paths between the structure and the ground. Some of those paths may be horizontal for a considerable distance. It will burn, explode, and/or electrocute anything in the way. Grounding a metal structure makes it safer.

However, surviving a direct lightning strike takes a lot more than just a single copper rod in the ground. To do it right, you'll need a soil analysis and a network of grounding rods that are bonded together. I think a better idea is to stay away from the gazebo (and the deck for that matter) when there's lightning in the area.

mrog
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Gazebos don't always conduct electricity as well as you do, since people are made mostly out of water. The current from a lightning strike may leave the gazebo and jump over to you and follow your body on its way to the ground. People conduct electricity very well. So ground your gazebo if you plan on being in it during a thunderstorm.

Khris
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    Can you provide some evidence or details for why you believe that a metal structure (likely power coated steel) is less conductive than a human? Steel is significantly more conductive than salt water, as an approximation of a human. – Hari Jul 02 '18 at 21:48