Lightning Protection System

[Ragin Cajun]

My thoughts regarding no exothermic welding at the roof would be to negate possibly causing a roof fire. Tar + fire/sparks from exothermic reaction = roof fire?

I've seen roof fires start hours after welding. Try to fight a roof fire, very hard to get a fire hose up there.

Neat about using building steel.

RC

 

[zyhml]

...
I see maybe a conflict with 250.60, since we are using the building steel as a down conductor. You can't use down conductors for lieu of an electrode. So then I could not ground a XFMR to building steel....

i personal agree this. But actually i saw this way was adopted wildly. How to understand "Air terminal conductors and driven pipes, rods, or plate electrodes used for grounding air terminals shall not be used in lieu of the grounding electrodes required by 250.50 for grounding wiring systems and equipment." in 250.60 and "Separation from lightning protection conductors is typically 1.8 m (6 ft) through air 900 mm (3 ft) through dense materials such as concret, brick, or wood." in 250.92
i suppose that means two electrodes are needed for LPS and power, of course they are bonding together. I am confusing.