Lightning downconductor make of steel?

Question

Copper is very expensive nowaday. Can we use galvanised steel to make lightning downconductor ? How much larger it has to be?

Answer 1

Are You talking about a lightning rod? Remember one thing.... Outside of pure gold, copper has the least resistance to electricity, making it an excellent conductor. Galvanized steel is more dense than copper and can work just fine but if your life depends on it you better make it approximately 10.4 times the size of the copper equivalent to perform the same function.

Answer 2

resistivity of 316 Stainless = 7.184E-07
resistivity of ingot iron = 1.105E-07
resistivity of copper, pure = 1.664E-08

Galvanized steel will have a resistivity somewhere in between Iron and 316 Stainless.
For a safety factor I'm using 316 Stainless for my calculations.
(d (steel) / d (copper))^2 = 71.84/1.664
(all other factors & units cancel out)
d(steel) = 6.57 d(copper)
oops!, better use iron!
d(iron) = 2.576 d(copper)
Since the copper rod is usually 1/2" dia., an iron rod would have to be at least 1.25" dia.

You might consider using aluminum:
d(Al)/d(Cu) =1.30, or d(Al) = 0.65, or 3/4"

Answer 3

whatever you make a conductor out of, you have to make sure that the heat it generates doesn't burn whatever you're interested in protecting. worse conductors generate more heat (see tungsten filaments in a light bulb), so it's possible that you can't use anything less conductive than copper. especially when you think of the large amount of current running through a grounding wire when a storm is in the area.

Answer 4

Ya.... you may use aluminium. Cheaper. Steel cannot as it may corrode over time. Corrosion meaning high resistance.... dangerous.

I would suggest you to use ESE system with aluminum downcomer for a highrise building. Can save cost.