KVA Load-Carrying Capacity of Wire1
Steel wire used as a
weatherproof covering is not to be
conductor permits long spans because
considered as insulation, although it
of its high tensile strength.
does prevent breakdowns on the lower
has about 10 to 15 percent as much
primary voltages caused by conductors
For all primary
distribution over 5,000 volts, bare
conductors are ordinarily used.
to some extent by the use of copper-
clad steel made by welding a copper
coating to the steel wire.
weatherproof covering is an effective
braid weatherproofing is preferred to
Improved types of
permitting rack-type distribution and
closely spaced secondary conductors.
covering, and layers of impregnated
No wire smaller than a No. 8 is to be
unspun cotton or impregnated rubber
used for secondary distribution or for
Before these newer type
any external transmission of power.
coverings are used, approval should be
previously, a wire size is selected on
the basis of the allowable voltage
(4) Primary distribution.
drop and the load to be carried. The
voltage drop is perhaps the more
volts, either bare or weatherproof
important criterion in that it causes
conductors may be used.