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RE: Grounding rebar

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Key to understanding this question is understanding
the UFER ground.  A typical UFER ground that I have
observed consists of placing a bare copper ground wire
in the concrete footing before the concrete is placed.
 When the ground current starts to flow in this wire
the water that is a natural part of dry concrete helps
the ions to flow through the concrete and into the
soil.  This same process ensures that the reinforcing
steel in the foundation is naturally grounded.  Thus
there is no need to ground the reinforcing.

Reference http://ecmweb.com/nec/code_top50nec_102506/.
 Part of which is included below:

?(A) Grounding Electrode. To provide a path to earth
for lightning, each building or structure must have
its disconnecting means [225.31] grounded (earthed) to
one of the following electrodes [250.50 and
250.52(A)]: 
?	Underground metal water pipe [250.52(A)(1)] 
?	Metal frame of the building or structure
[250.52(A)(2)] 
?	Concrete-encased steel [250(A)(3)] 
?	Ground ring [250.52(A)(4)]
Where none of the above grounding electrodes are
available at a building or structure, then one or more
of the following must be used: 
?	Ground rod [250.52(A)(5)] 
?	Metal underground systems [250.52(A)(7)]
Exception: A grounding electrode isn?t required where
only one branch circuit serves the building or
structure. For the purpose of this section, a
multiwire branch circuit is considered to be a single
branch circuit.?

This supports my position that they are not trying to
ground the foundation but rather using the foundation
to complete the ground.  If the electrical engineer
really thinks he needs to ground the foundation he
should go back to school.

I can imagine that somebody may try to save on the
ground wire and connect it to a rebar.  I would
require that they not use one of the bars I have
required.  If this is an installation that will have
heavy ground currents such as an electrical power
plant I would get much more concerned about corrosion
resulting from the grounding currents.

There is one situation where this does not work and
that is when the footing concrete is separated from
the earth by a non-conducting waterproofing membrane. 
It is my belief that the membrane prevents the ground
from being effective and as a result you could end up
with a floating ground.


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