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I am installing a conventional copper rod on the top of a metal roof top.

I am concerned whether the roof top and the spike rod base are to be insulated with porcelain insulator?

Scenario: When lightning strikes the spiked air rod, part of the electricity is conducted by the GI roof top which is in turn connected to concrete terrace of the house AND also the electricity is conducted to the ground via copper strip cable.

I am worried, how would I connect the spike rod to the GI roof sheet. Whether any isolation/insulation is needed? My poor electrician says, it can be connected with a iron stand (he would screw iron stand between GI sheets and the copper spike rod) and would pose no problems since the lightning bolt is transferred to the ground.

In the second rod image I can see the 4 screws, since screws conduct lightning I am just assuming its not a good option.

Any help is greatly appreciated.

a steel roof

a drawing of a lightning rod

FreeMan
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  • There is a lot more to this than just your questions. A good system involves four levels in design (rings of protection), at minimum. You cannot look to just one in isolation of the rest. There are a few good books on this topic, if this is DIY study for you. When I wake up, again, I may select a couple titles to recommend. But there are experienced professionals, as well. – jonk May 09 '22 at 10:24
  • I am not able to understand better. Any insights are really appreciated! –  May 09 '22 at 10:50
  • Would imagine the idea is to give an easier path from spikes to ground than to roof, so think a way insulate the rod from the roof is needed, so lighting will take the easy path away. Those rods seem to be electrically conductive from top to base/roof. The site might not always sell proper electrical safety equipment. – crip659 May 09 '22 at 12:05
  • Have you contacted the manufacturer of the spike rod? – JACK May 09 '22 at 12:05
  • This is an excellent question not sure why the down vote, reversed, my comment would be how big of an insulator do you think it would take the lightning just traveled a mile or more through air a good insulator in itself. – Ed Beal May 09 '22 at 13:18
  • @EdBeal Think the idea of an insulator is to make one path harder than the other. Not much will stop lighting getting to point B, but can make going though point A first harder. – crip659 May 09 '22 at 13:31
  • @crip659, exactly my point insulation won’t make much of a difference if any for a strike, I have first hand experience on repairs of 2 systems one direct strike that the service panel was itself mostly destroyed. And an indirect strike tree hit next to a home with a car width parking between them that fried things with the switches turned off. I brought this up as most won’t do anything close to making a difference but isolation would help the roof from being the primary target. – Ed Beal May 09 '22 at 16:34
  • Lightning just traveled several thousand feet just to greet you at your house. A little insulator will make zero difference. You are better off making sure that the metals that are in contact with each other are compatible and will not cause corrosion issues. Paint or powder coat don't work well to prevent galvanic corrosion. – Aaron May 09 '22 at 19:03
  • How about adding a nylon insulator something like this https://5.imimg.com/data5/XH/VD/LM/SELLER-5779732/stainless-steel-lightning-arrester-500x500.jpg that will resist the conducivity between rod and roofing panel? – Code Guy May 10 '22 at 04:03

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