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250-115.
Connection
to Electrodes.
The grounding
conductor
shall be connected
to the grounding
electrode
by exothermic
welding,
listed lugs, listed
pressure
connectors,
listed
clamps,
or other listed
means.
Connections
depending
on solder shall not be
used.
Ground
clamps shall be listed for the materials
of the grounding
electrode
and the grounding
electrode
conductor
and, where used on pipe, rod, or
other buried
electrodes,
shall also be listed for direct
soil burial.
Not more than one conductor
shall be
connected
to the grounding
electrode
by a single
clamp or fitting unless the clamp or fitting is listed for
multiple
conductors.
One of the methods
indicated
in (a), Co), (c), or (d)* below shall be used.
(a) Bolted
Clamp.
A listed bolted clamp of cast
bronze
or brass, or plain or malleable
iron.
(b) Pipe Fitting,
Pipe Plug, etc. A pipe fitting,
pipe
plug, or other approved
device screwed
into a pipe or
pipe fitting.
(c) Sheet-Metal-Strap
Type Ground
Clamp.
A
listed sheet-metal-strap
type ground clamp having
a
rigid metal base that seats on the electrode
and
having
a strap of such material and dimensions
that it is
not likely to stretch during
or after installation.
810-1.
Scope.
This article covers radio and
television
receiving
equipment
and amateur
radio
transmitting
and receiving
equipment,
but not
equipment
and antennas
used for coupling
carrier
current to power line conductors.
810-15. Grounding.
Masts and metal structures
supporting
antennas shall be grounded in accordance
with Section 810-21,
810-21.
Grounding
Conductors
-- Receiving
Stations.
Grounding
conductors
shall comply
with
(a) through (j)below.
(a) Material.
The grounding
conductor
shall be of
copper,
aluminum,
copper-clad
steel, bronze,
or
similar corrosion-resistant
material.
(b) Insulation.
Insulation on grounding conductors
shall not be required.
(c) Supports.
The grounding conductors shall be
securely fastened in place and shall be permitted
to
be directly attached to the surface wired over without
the use of insulating supports.
(d) Mechanical
Protection.
The grounding
conductor
shall be protected
where
exposed
to
physical
damage,
or the size of the grounding
conductors
shall be increased
proportionately
to
compensate
for the lack of protection.
(el Run in Straight Line.
The grounding
conductor
for an antenna
mast or antenna
discharge
unit shall
be run in as straight a line as practicable
from the
mast or discharge
unit to the grounding
electrode.
(f) Electrode.
The grounding
conductor
shall be
connected
as follows:
(1) To the nearest
accessible
location
on (1) the
building
or structure
grounding
electrode
system
as
covered in Section 250-81, (2) the grounded
interior
metal water piping
system
as covered
in Section 250-
80(a), (3) the power service
accessible
means
external
to enclosures
as covered
in Section 250-71(b),
(4) the
metalic power service
raceway,
(5) the service
equipment
enclosure,
or (6) the grounding
electrode
conductor
or the grounding
electrode
conductor
metal enclosures;
or
(2) If the building
or structure
served
has no
grounding
means,
as described
in (0(1), to any one of
the individual
electrodes
described
in Section 250-81;
or
(3) If the building or structure served has no
grounding means, as described in (0(1), or (f)(2), to
(1) an effectively grounded metal structure or (2) to
any of the individual
electrodes described in Section
250-83.
(gi Inside or Outside Building.
The grounding
conductor shall be permitted to be run either ir_lde
or outside the building.
(h) Size. The grounding conductor shall not be
smaller than No. 10 copper or No. 8 aluminum or
No. 17 copper-clad steel or bronze.
(i) Common Ground. A single grounding
conductor shall be permitted for both protective and
operating purposes.
(j) Bonding
ot Electrodes.
A bonding
jumper not
smaller
than No. 6 copper or equivalent
shall be
connected
between
the radio and television
equipment
grounding
electrode
and the power
grounding
electrode
system
at the building
or
structure
served
where separate
electrodes
are used.
Appendix: Other Information
49
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