Bill,

You would do us all a great service if you would explain why, "The roof-mounted
requirement was a complete mistake--and
potentially dangerous in most cases." To the trained eye, as Doug Wells points
out, a rooftop PV array looks like one enormous air terminal. You guys are
agreeing it makes sense to ground it by passing a conductor as small as #14
through a residence. NFPA also publishes a lightning protection standard. Do you
guys talk to each other?

Of course any and all electrodes should always be bonded to form an electrode
system.
It is extremely discouraging that six years have passed and the code still can't
get this right or even present a comprehensible English sentence.

You state, "Bottom line is that any building that already has a grounding
electrode
should not have an additional electrode added."  Moments earlier in the
presentation all ten of you were just fine with a DC electrode in addition to
the existing AC electrode, whether it was bonded to the AC electrode with a
buried #4 conductor or a #14 equipment ground in a cable run through a house. A
grounding electrode is a grounding electrode. You can't have it both ways.

Dick


--- You wrote:
Dick,

It sounds like you are not a big Mike Holt fan. There is no requirement for
that. The language in the 2008 NEC was poor, at best. It was a complete mess
up of a proposal that John Wiles and I was involved with--sounds like you
were involved as well. A member of the CMP13 took the proposal and
essentially destroyed it. 

The original proposal was to require an electrode on ground-mounted
structure. The roof-mounted requirement was a complete mistake--and
potentially dangerous in most cases.

My approach is to work with another member of our CMP4 panel to write an
article for the IAEI News and explain what was intended. Since the language
is very ambiguous, that can work in the favor of providing an opinion that
is a safe version of 690.47(D). 

Bottom line is that any building that already has a grounding electrode
should not have an additional electrode added.

Bill.
--- end of quote ---

