, 1922-06-08
protector or arrester.

pIOletlOT OF dTFoSIeT.
Note:-A grounding switch will
not be accepted in lieu OF the above
mentioned protective device but II de-
sired. a grounding switch may be
provided in addition to the lightning
arrester providing 1t is SO arranged
as to not ~disconnect or in any way in
terfere with the lighting arrester.
"List of lightning arresters which
have been tested and approved for
use with radio systems may be Sc
cured from this Bureau.
S. The lightning arrester as re-
CURED in Rule No. 4 must be located
outside of the building and must be
permanently and effectively insulated
therefrom. Must be Of a weather
proof type or protected from the
weather. Must be connected to the
"lead-in-wire" as near as possible to
the point where the lead-in-wire en-
tiers the building.
6. The ground wire Of the light
ming arrester must be in accordance
with the following requirements:
(a) Must be Of copper and not
smaller than No. 10 B. & S. gauge
and where exposed to mechanical in
jury must be protected.
NUle.-" mere the BIOuuu wire Is
Il on the wall of a building located
directly on a street. alley. or drive
exposed to mechanical injury and
must be provided with substantial
protection extending at least seven
feet from the ground.
% Must have an approved insul-
at!ng covering.
ic) Must run in as straight a line
ne nnSSjh1a tn a onn6 narmanpn
ground" This may be obtained by
a three-fourths inch galvanized iron
pipe driven into permanently damp
earth. or by a connection to a water
pipe.
(d) The ground connection to the
ground pipe or water piping must be
made either by means Of an approved
ground clamp securely bolted t o the
pir" after it has been freed from all
RUS. paint. or scale; Or by screwing
tightly into the pipe or a pipe fitting
a brass plug having a lug for the
ground conductor. or by other equiv
alont means.
The ground wire must be attached
to the clamp or to the plug by means
Of solder or by an approved solderless
connector.
RADIO TRANSMITTING STATIONS
tNot E,>ceiving)
Ia, Aerial antennas for transmit
ting stations must conform to the re-
Quirements of Rule No. /, for Re
ceiving Stations"
th) The "lead-in-wire" from the
antenna to the apparatus within the
building should be of a size equal to
the conductors of the antenna but
must not be less than No. II B. & S.
gauge and should be of copper Or
aluminium. Must be securely sup
ported on approved insulating sup
ports which will maintain the con-
at least five inches clear OF
surface of the building wall;
must be insulated where entering the
building by a continuous tube Or
bushing composed of an approved
material such as Bake
lite" or other equally good %insulat-
ing composition adapted for high fire.
quency service. The insulating tube
bushing must extend five inches
beyond the surface of the wall on
both sides and must slope upward
from the outside; porcelain tubes
will not be approved for this pur-
pose.
(c) All wiring Except high fire.
quency %circuits) inside the building
used in connection with radio trans
apparatus must have an ap-
proved rubber insulating covering
and must be securely separated and
on insulators in accordance
with Rule go" National Electrical
Code. High frequency conductors
need not be insulated but must be
securely mounted on approved high
insulators which will per-
maintain a 5-inch separa-
ton between the conductors and sur
face on which the insulators are
mounted. Must not come nearer
than s inches Of any electric light or
power wires in the building.
(d) Aerial antennas for transmit
ting must be protected from light
ming discharges by an approved
ground switch connected to the
"lead-in-wire" as e as possible to
the point where the "lead-in-wire'
enters the building and mounted so
that Its current-carrying parts will
be at least five inches clear Of the
building wall: must be located IN a
readily accessible place on the out
side OF the building: must be kept in
the grounding position at all times
when the station is not in operation:
be Of an approved design with
a rated capacity Of not less than
sixty amperes and must have a break
distance Of at least five inches. The
base OF the switch must be OF ap-