In reading through what I could find on Ufer grounds and rebar bonding I
found the following:
1) There are two standard grades of rebar commonly used: 40 and 60. Neither
is intended to be welded, but the 40 has a lower carbon content and is more
suitable for welding.
2) Rebar that is intended to be welded is referred to as A706 and usually
has "weldable" or something similar imprinted on it.
There was a lot of conflicting information about how to bring the Ufer
ground out of the concrete. In dry climates or indoors, there were a lot of
comments about just bringing the rebar out of the concrete. In wet climates,
many of the comments said that the rusting of the rebar will damage the
concrete however. There was some mention of bonding copper cable to the
rebar inside the concrete and bringing the copper out for connection, but I
found other comments about the concrete degrading the copper. I didn't see
anything about galvanizing at least the part of the rebar coming out of the
concrete; it seems like this might be a viable alternative.
I probably missed it in the archives, but wouldn't it make sense to bond the
rebar cage in the concrete to the base tower section in the concrete? The
three tower legs would then be your Ufer ground connection and wouldn't
require anything else to penetrate the concrete.
I saw a couple references to driving one or more ground rods into the bottom
of the base hole and bonding them to the rebar cage. Any thoughts as to
positives or negatives of doing this?
Doug
K4DDR
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