The Washington herald., 1922-05-28
SAFETY DEVICES
FOR TRANSMITTERS
REQUIRED BY LAW
Electrical Experts Pro
pose Changes in Code
Rule S6.

y EhoiO receiving setsp was printed
n full. As there are many trans
hitting sets in the District the full
Z evision as regards transmitting
'ets Is given. Although the sus~
sestions made are embodied in the
orm Of a proposal. they have been
approved by the standing commit
zee on signal systems. and will be
ubmitted to the electrical commit
ee for Incorporation into the 1923
rdition Of the National Electrical
-ode.
Questions concerning the relative
nerits Of different types Of light
ling arresters, switches and safety
saps, and details concerning their
installation should be referred to
he electrical division. District
suilding. Because OF the danger of
lightning during the summer
months adequate protection should
BE made against nre- If the re-
Iuiremsnts as outlined are COM
hied with. there will be no danger
rom fire or lighting because of
he radio set. Contrary to rumor.
= TO change has been made recently
\ n insurance rates because OF radio
installation Insurance companies
ecognize specifications prepared by
he National Board Of Fire Under
writer's
For Transmitting stations.
MISUNDERSTANDING outside of
buildings shall not cross over or
Inder electrict light or power
wires of any circuit OF more than
90 volts or railway trolley, or
eeder wires, nor shall 1t be SO To-
'ated that a failure of either the
Gntenna or of the above mentioned
dectric light or power wires can
esult in a contact between the
Intenna and such electric light or
Iower wires.
Antennas shall be constructed and
Installed in a strong and durable
manner and shall be so located as
prevent accidental contact with
light and power wires by sagging
r swinging.
Splices and joints in the antenna
pan shall, unless made with ap-
'roved clamps or splicing devices.
Ie soldered.
Lead-in Wires.
Lead-In wires shall be of cop
per. approved copper-clad steel o.
'ther metal which will not corrode
excessively and in no case shall
D hey be smaller than No. IA B. and
J. gage.
Antenna and counterpoise con-
luctors and wires leading there
rom to ground switch. where at
ached to buildings, must be firmly
mounted Ave inches clear of the sur
ace OF the building, on non-ab-
orptive insulating supports such as
reated wood pins or brackets
.quipped with insulators having not
ess than five inch creepage and air
zap distance to infiammable or
conducting material. Where de-
ired approved suspension type in
ulators may be used.
In passing the antenna or counter
,oise lead-in into the building a
ube or bushing OF nonabsorptive
Insulating material shall be used
md shall be installed so as to have
creepaEe and air-gap distance Of
Z least five inches to any extran-
pous body. Tf porcelain or other
raEile material is used 1t shall be
Installed so as to be protected from
Mechanical injury. A drilled win
low pane may be used in place of
ushing provided five inch creepage
md air-gsp distance is maintained.
Protective Grounding switch.
\ double-throw knife switch
faving a break distance of four
|. inches and a blade not less than
ne-eighth inch by one-half inch
!. hall be used to join the antenna
md counterpoise lead-ins to the
round conductor. The switch may
,e located inside or outside the
uilding. The base of the switch
hall be OF nonabsorptive insulating
material. Slate base switches are
Tot recommended This switch
must be so mounted that its cur
ent-carrying parts will be at least
I've inches clear of the building
vail or other conductors and To-
Inc between the lead-in conductors
md the point where ground connec-
ion is made The conductor from
rounding switch to ground con-
tection must be securely supported.
Protective Ground Wire.
Antenna and counterpoise con-
Iuctors must be effectively and per-
nanently grounded at all times
Fhen station is not in actual opera
ion (unattended) by a conductor at
east as large as the lead-in and
n no case shall 1t be smaller than
70. IL B. and S. gage copper or
pproved copper-clad steel. This
round wire need not be insulated
IT mounted on insulating supports.
he ground wire shall be run in as
traight a line as possible to a
ood permanent ground. Preference
hall be given to water piping. Gas
hping shall not be used for the
round connection Other permIs-
ible grounds are the grounded
teel frames of buildings and other
rounded metal work in buildings
nd artificial grounding devices
uch as driven pipes, plates, cones,
tc. The ground wire shall be pro,
ected against mechanical injury.
N approved ground clamp shall be
sed wherever the ground wire Is
onnected to pipes or piping.
Operating Ground Wire.
The radio operating ground con-
uctor shall be of copper strip not
.ss than three-eights inch wide by
ne-sixty-fourth inch thick. or of
opper or approved copper-clad