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Five things need to be considered when routing aerial drops:
Ground clearance
Power separation
Pole to pole spans
Terminal to premises spans
Stringing sag
Ground clearance
Aerial trespass over private property must be avoided. In order to avoid aerial trespass, route the wire to the
mid-span and put on span clamps. Downhill slopes may cause the customer to be required to provide a
clearance pole or mast. Do not sacrifice clearances when running in a service. There are specific clearances
for airports, railway crossings, trolley wires and swimming pools.
Power separation
Aerial crossings under power conductors should be as close to right angles as possible.
Telephone plant is never to be placed above power conductors.
It is not permissible to place drop wire directly under primary power; it must be placed below a messenger.
Cable clearances are measured from the lowest power conductor at maximum sag and a straight line
between telephone supports.
It is recommended that you follow the electrical utility sag and keep at least 0.6 m (2 feet) separation from
power at the pole and 0.3 m (1 foot) at the premises, while maintaining ground clearances.
A span of wire can be placed temporarily to the terminal; call facilities and have a new RA terminal installed.
Pole to pole spans
Where no cable, messenger or electrical utility exists, pole-to-pole spans of drop wire must not exceed 60 m
(200 feet).
Pole to pole spans of drop wire on private property must not exceed 50 m (164 feet).
Terminal to premises spans
Use of existing drop wire is acceptable. Two, four and six-conductor drop wire should not be spliced. Use a
drop wire guard or reroute the drop if trees are in the way. Trimming trees on private property should be
limited. The owner is responsible for removing any limbs and large branches.
New drop wire span length between the pole and building must not exceed 45 meters (148 feet). 100 meters
(328 feet) of drop wire is provided to the customer with a new installation.
Stringing sag
If a drop already exists, hang the new drop with the same amount of sag, as long as it meets clearance
standards. Sagging will depend on the time of year; the warmer the weather the more the drop will sag. Sag
clearance is measured at the point in the span closest to the ground. In mid span situation where a ladder is
placed on the messenger. The weight of the technician on the messenger will bow the distribution cable
towards or from the house slightly. This is important to know if attaching the drop at the house first or
cutting and existing drop. The sag will changed once the ladder is removed, either tighter or looser. Caution
must be taken if cutting a drop under tension as the tech may get “shot” backwards off the ladder.
Aerial Building Attachment
