If you do the below rebar grounding, make sure your water system is also
grounded at the same potential.
Just make sure that none of your copper water pipe is touching the rebar in
the cement, the potential from a lightning strike can arc between the two
and create a hole in the copper water pipe.
Don't ask me how I know this....
Jim - KR9U
--------------------------------------
> It seems like if the only thing you need is a large area of this
> allegedly conductive concrete stuck in the ground, why not ground
> everything to the concrete slab your house sits on!!
>
which, in fact, is what they do these days. The lightning protection system
in the building is tied to the structural steel which in turn is tied to the
rebar in the foundation/slab. This is very common in large multistory
buildings, for instance.
In residential construction in Southern California (a very low lightning
area, though) a Ufer ground is required. So, in fact, everything is grounded
to the slab my house sits on. Nothing beats hundreds of square feet of
contact area for a good reliable ground.
I've worked in buildings in New Mexico which were essentially large steel
sheds (slab poured, structural steel supports bolted on, then steel panels
screwed onto the structural steel). The lightning protection earth
connection came up as a stranded AWG 2 (or thereabouts, I didn't measure
it..) cable from the slab. It was bolted with a lug to the steel. The air
terminals were connected to cables that ran down the outside of the building
and were connected to the same cable that came out of the slab.
Interestingly, they did not depend on the bolts holding the steel to the
concrete on that building for electrical connection. I think it's because
the bolts were chemical anchors (epoxied into holes) installed long after
the slab was installed, but the engineer wasn't around to ask when I was
thinking about it.
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