Outdoor antennas and lead-in conductors shall be securely
supported. The antennas or lead-in conductors shall not be
attached to the electric service mast. They shall not be at-
tached to poles or similar structures carrying open electric
light or power wires or trolley wires of over 250 volts be-
tween conductors. Insulators supporting the antenna con-
ductors shall have sufficient mechanical strength to safely
support the conductors. Lead-in conductors shall be securely
attached to the antennas.
810.13 Avoidance of Contacts with Conductors
of Other Systems
Outdoor antennas and lead-in conductors from an antenna to
a building shall not cross over open conductors of electric
light or power circuits and shall be kept well away from all
such circuits so as to avoid the possibility of accidental con-
tact. Where proximity to open electric light or power service
conductors of less than 250 volts between conductors cannot
be avoided, the installation shall be such as to provide a
clearance of at least 600 mm (2 ft).
Where practicable, antenna conductors shall be installed
so as not to cross under open electric light or power conduc-
810.21 Bonding Conductors and Grounding
Electrode Conductors — Receiving Stations
Bonding conductors or grounding electrode conductors shall
comply with 810.21(A) through (K).
(A) Material. The bonding conductor or grounding elec-
trode conductor shall be of copper, aluminum, copper-clad
steel, bronze, or similar corrosion-resistant material. Alumi-
num or copper-clad aluminum bonding conductors or
grounding electrode conductors shall not be used where in
direct contact with masonry or the earth or where subject to
corrosive conditions. Where used outside, aluminum or
copper-clad aluminum conductors shall not be installed
within 450 mm (18 in.) of the earth.
(B) Insulation. Insulation on bonding conductors or
grounding electrode conductors shall not be required.
(C) Supports. The bonding conductors and grounding
electrode 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.
Exception: Where proper support cannot be provided, the
size of the bonding conductors and grounding electrode
conductors shall be increased proportionately.
(2) In Buildings or Structures with Grounding Means. If
the building or structure served has no intersystem bonding
termination, the bonding conductor or grounding electrode
conductor shall be connected to the nearest accessible loca-
tion on the following:
(1) The building or structure grounding electrode system as
covered in 250.50
(2) The grounded interior metal water piping systems,
within 1.52 m (5 ft) from its point of entrance to the
building, as covered in 250.52
For more information on the use of a metal water piping sys-
tem, see the commentary following 250.52(A)(1).
(3) The power service accessible means external to the
building, as covered in 250.94
(4) The nonflexible metallic power service raceway
(5) The service equipment enclosure, or
(6) The grounding electrode conductor or the grounding
electrode conductor metal enclosures of the power ser-
A bonding device intended to provide a termination
point for the bonding conductor (intersystem bonding) shall
not interfere with the opening of an equipment enclosure. A
bonding device shall be mounted on non-removable parts. A
bonding device shall not be mounted on a door or cover even
if the door or cover is non-removable.
(H) Size. The bonding conductor or grounding electrode
conductor shall not be smaller than 10 AWG copper, 8 AWG
aluminum, or 17 AWG copper-clad steel or bronze.
(I) Common Ground. A single bonding conductor or
grounding electrode conductor shall be permitted for both
protective and operating purposes.
(J) Bonding of Electrodes. A bonding jumper not smaller
than 6 AWG copper or equivalent shall be connected between
the radio and television equipment grounding electrode and
the power grounding electrode system at the building or struc-
ture served where separate electrodes are used.