Dr M J DiGirolamo wrote:
> Don,
>
>
>
> I built my cage from "weld quality rebar" and it was welded by a friend.
<snip>
I wanted to employ a Ufer ground and that calls for a welded
> cage.
Actually, Ufer grounds (Concrete Encased Grounding Electrodes, in
code-speak) don't require welded rebar, even if you're using the bar as
the conductor (at least in the 2005 NEC)
Art 250.50(A)(3) says: 20 feet of AWG 4 (or larger) bare copper or steel
reinforcing bar at least 1/2" in diameter. And.. "Reinforcing bars shall
be permitted ot be bonded together by the usual steel tie wires or other
effective means"
This is one of those sort of clunky areas, I have to confess. It would
technically be ok to have a series of 1 foot stubs, wired together, to
make up the 20 feet. But nobody would claim that this is as good as a
single 20 foot chunk. I can't find it now, but there is some research
that did show that 2 overlapped >10foot pieces wired together were as
good as a single 20 foot piece.
Your engineer or local jurisdiction may require welded rebar for this
use, of course. The NEC is just a minimum standard.
Jim
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