Download TYING IN CONDUCTORS Tie wire fastens the conductor and

TYING IN CONDUCTORS
Tie wire fastens the conductor and insulator together. Conductors can be tied in
various ways, but the ties shown in figure below:
In tying in conductors, observe the following procedures: Always use new,
fully annealed wire for ties. Hard- drawn wire is brittle and cannot be pulled
up against the conductor and insulator. Use the proper size wire.
For No. 8 bare, use No. 8 bare.
For No. 6 or No. 4 bare, use No. 6 bare.
Use No. 4 bare for a No. 2 conductor.
Use No. 2 bare wire for No. l/O through 4/0 bare conductor.
Use a piece of tie wire that is long enough to make the complete tie, with
enough left over to allow grasping. After the tie is completed, cut off the
excess and form a loop, or eye, at the end of any projecting end of the wire.
Make positive contact between the wire and conductor to avoid chafing and
to limit possibilities of causing interference with radio communications.
Hold the tie wire tight against the insulator as you make your wraps around
the insulator and the conductor wire.
Special reminder—when using an aluminum conductor, you are required to
cover it with armor rod at each insulator to provide physical protection
against rubbing or pitting caused by the elements. Another important
requirement is the use of ACSR-rated dead- end shoes, splice connectors,
and all other devices that come in direct contact with an aluminum
conductor. This is to prevent electrolysis that occurs from the physical
contact of dissimilar metals.
Plyethylene pin type insulators should be used with tree wire, spacer cable, and, in
some instances older poly/XLPE covered conductor, because the material they are
made from is dielectrically compatible with the material making up the covering on
the conductors.
When the above (unskinned) covered conductors are tied to a polyethylene
insulators, the voltage stress across the two dielectrics in series (the conductor
covering and the polyethylene insulator) will be divided nearly equally between the
series impedances, with neither one being over stressed. {good}
The same coverd conductor used with a porcelain pin insulator has the major
voltage drop across its conductor covering, since porcelain and the plastic are
dielectricly incompatiable. The ultimate result of this surface discharge condition,
along with the effects of time and weather, is eventual erosion of conductor
covering to the point of puncture and flashover possibly to the point of causing radio
interference. {bad}
Polyethylene pin insulators shall not be used on bare conductors on distribution
supply lines designed to carry 140°C conductor temperatures, as the plastic pin
insulators begin to melt at approximately 120°C.
Polyethylene pin insulators should not be used on bare conductors in salt water or
other environmentally contaminated areas, a full power arc voltage exists across the
contaminated insulator leakage surface which may develop heat sufficient to melt the
insulator. A poly/XLPE covered conductor tied to a polyethylene pin insulator will
not experience this phenomenon.
Exsisting construction -crossarm-older nonstandard coverd wire on glass. Examin
conductor covering for erosion, cracks or puncture holes. If significant cover
damage exists, skin covering back at least 30 inches each side of the pin insulator
and examine conductor for strand damage. If strand damage exists, sleeve out with
new conductor. Skin conductor back beyond 30 inches either side of the pin
insulator if necessary. Clean or install new radio free porcelain pin insulator and retie
using bare tie compatible with bare conductor.
Where no conductor covering damage exists, remove existing porcelain insulator
and install new polyethylene pin type insulator. Retie using TPR covered aluminum
tie wire.
Use With Bare Conductors
Polyethylene pin insulators shall only be used on bare conductors in areas where
vandalism is known to exist. Bare metallic ties compatible with the bare conductor
material shall be used for tying.
Polyethylene pin insulators shall not be used on bare conductors on distribution
supply lines designed to carry 140°C conductor temperatures, as the plastic pin
insulators begin to melt at approximately 120°C.
Polyethylene pin insulators shall not be used on bare conductors in salt water or
other environmentally contaminated areas, as full power arc voltage exists across
the contaminated insulator leakage surface which may develop heat sufficient to melt
the insulator. A poly/XLPE covered conductor tied to a polyethylene pin insulator
will not experience this phenomenon.