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are 3 feet long, four-pin arms 4 feet, and siz-pln arms 6 feet. Figure
5 shows the details of the standard method of mounting cross-arms, and
also gives the specifications of the necessary pole hardware used in
securing them to the poles.
Pins and Insulators .
25.
l-l/2" X 9" genuine locust pins represent standard prac-
tice in reference to pins. As to insulators deep groove double petti-
coat glass insulators have long been accepted as standard for electric
lifting service.
Anchors
The Mathews #502-R galvanized guy anchor is of thensorew
type", which has the advantage over the^spread" type of avoiding the
necessity of digging a hole, its application is single and quick, and
therefore it is used to a large extent in guying poles which do not
carry excessively heavy wires.
Street Lamp Suspension:-
To obtain the best illumination of the streets ^en
tungsten lamps, spaced at distances of approximately 100 yards, are
used, the lasBpa should be placed in the middle of the street • This
method of suspension requires two poles to each lamp, but the better
results obtained warrant the additional expense. The bractet arm sus-
pension requires but one pole; but it is impossible to get the lamp out
into the middle of the street, and therefore it is not to be recommended
for use in street illumination, although it serves well in lifting
country roads. The bottom of the lamp should never be lower than 20 feet
from the ground, so that a man standing on a load of hay will clear it.