Greetings,
You are right. I thank everyone very very much for their help. This is the
post which clearly shows me the requirements set forth by the NEC requiring
me to run an additional 40 feet of grounding wire in parallel with a 3/4"
copper pipe to within 5 feet of where the water pipe enters the building. I
am still a little worried about the inspector's "six feet" "ground the water
pipe" wording but I am going to try this and see what he says when he comes
back.
You guys are great,
William
"HorneTD" wrote in message
nk.net...
William Deans wrote:
Greetings,
I think what the inspector means is that he won't count my grounding
from
the circuit breaker to the water pipe as a second grounding rod because
it
is grounded to the water pipe more than 6 feet from where the water pipe
enters the building. What he actually said though was that the water
pipe
needed to be grounded within six feet of where it enters the building.
I called up to ask for clarification and it was reiterated that I needed
to
ground the water pipe within six feet of where it enters the building.
This
sounded like nonsense to me but I didn't want to argue with the
inspector
any more than I already was. Does this rule exist? Every word I say to
this guy he somehow seems to turn into an argument in seconds so I don't
want to get back into it with him. He is very clear on what he wants
"GROUND THE WATER PIPE WITHIN SIX FEET OF ENTERING THE BUILDING" but it
makes no sense to my little non-inspector brain.
Maybe there is a very good reason for it that I just don't understand.
Thank you for your time and energy,
William
William
As you can see by reading the section below the underground metal water
pipe must be used as a grounding electrode. The piping is grounding the
system rather than being grounded. If the interior water piping were
metallic and the underground supply piping were not you would still have
to bond the piping to the grounded service conductor. Bonding
connections can be made at any convenient point in an interior metallic
piping system. A grounding connection to underground metal piping must
be made close to were the piping enters the building in order to reduce
the chance of the grounding connection being isolated from the
underground piping by later changes in the interior piping system. The
conductor that is used to ground the grounded service conductor to the
water piping must be number four AWG copper. The fact that it is over
forty feet away is just tough luck.
250.50 Grounding Electrode System.
If available on the premises at each building or structure served, each
item in 250.52(A)(1) through (A)(6) shall be bonded together to form the
grounding electrode system. Where none of these electrodes are
available, one or more of the electrodes specified in 250.52(A)(4)
through (A)(7) shall be installed and used.
250.52 Grounding Electrodes.
(A) Electrodes Permitted for Grounding.
(1) Metal Underground Water Pipe. A metal underground water pipe in
direct contact with the earth for 3.0 m (10 ft) or more (including any
metal well casing effectively bonded to the pipe) and electrically
continuous (or made electrically continuous by bonding around insulating
joints or insulating pipe) to the points of connection of the grounding
electrode conductor and the bonding conductors. Interior metal water
piping located more than 1.52 m (5 ft) from the point of entrance to the
building shall not be used as a part of the grounding electrode system
or as a conductor to interconnect electrodes that are part of the
grounding electrode system.
(5) Rod and Pipe Electrodes. Rod and pipe electrodes shall not be less
than 2.5 m (8 ft) in length and shall consist of the following materials.
(a) Electrodes of pipe or conduit shall not be smaller than metric
designator 21 (trade size 3/4) and, where of iron or steel, shall have
the outer surface galvanized or otherwise metal-coated for corrosion
protection.
(b) Electrodes of rods of iron or steel shall be at least 15.87 mm (5/8
in.) in diameter. Stainless steel rods less than 16 mm (5/8 in.) in
diameter, nonferrous rods, or their equivalent shall be listed and shall
not be less than 13 mm (1/2 in.) in diameter.
This next section covers how the Grounding Electrode System is
installed. As you can see it requires that the underground metal water
piping be supplemented by one other electrode to guard against the
possibility that the continuity of the underground metal water piping
will be broken by future plumbing work.
250.53 Grounding Electrode System Installation.
FPN:See 547.9 and 547.10 for special grounding and bonding requirements
for agricultural buildings.
(A) Rod, Pipe, and Plate Electrodes. Where practicable, rod, pipe, and
plate electrodes shall be embedded below permanent moisture level. Rod,
pipe, and plate electrodes shall be free from nonconductive coatings
such as paint or enamel.
(B) Electrode Spacing. Where more than one of the electrodes of the type
specified in 250.52(A)(5) or (A)(6) are used, each electrode of one
grounding system (including that used for air terminals) shall not be
less than 1.83 m (6 ft) from any other electrode of another grounding
system. Two or more grounding electrodes that are effectively bonded
together shall be considered a single grounding electrode system.
(C) Bonding Jumper. The bonding jumper(s) used to connect the grounding
electrodes together to form the grounding electrode system shall be
installed in accordance with 250.64(A), (B), and (E), shall be sized in
accordance with 250.66, and shall be connected in the manner specified
in 250.70.
(D) Metal Underground Water Pipe. Where used as a grounding electrode,
metal underground water pipe shall meet the requirements of 250.53(D)(1)
and (D)(2).
(1) Continuity. Continuity of the grounding path or the bonding
connection to interior piping shall not rely on water meters or
filtering devices and similar equipment.
(2) Supplemental Electrode Required. A metal underground water pipe
shall be supplemented by an additional electrode of a type specified in
250.52(A)(2) through (A)(7). Where the supplemental electrode is a rod,
pipe, or plate type, it shall comply with 250.56. The supplemental
electrode shall be permitted to be bonded to the grounding electrode
conductor, the grounded service-entrance conductor, the nonflexible
grounded service raceway, or any grounded service enclosure.
The point of attachment of the Grounding Electrode Conductor is a local
matter. Some electric utilities require that the connection be made in
the meter enclosure while others specifically forbid this. Some
utilities require that it be connected to the grounded service conductor
immediately adjacent to the demarcation point. For an overhead service
the demarcation point is the splices between the overhead service
drop, which is owned and maintained by the utility, and the service
entry conductors, that are owned and maintained by the building owner.
I hope that this answers your question if you have more just ask.
--
Tom H
|