General Order 64-A
Section VII
Detailed Construction Requirements For Trolley Lines
(Class T Circuits)
77.5 Fastenings.
Messenger and span wire
attachments shall have a strength at least equal to that of the strand to which
they are attached.
Cedar and other soft-wood poles
to which any span wire or messenger having an ultimate strength of 5000 pounds
or more is attached, shall be protected by suitable shims, and where necessary
with hooks, lag bolts or other equivalent means to prevent the span wire or messengers
from slipping along the pole.