Joint Pole I
Power, CATV, Telephone, Traffic SignalsThis
pole supports an enormous transmission line, probably at least 69-Kv,
possibly even higher. It also supports:
- Primary distribution.
- Secondary distribution.
- CATV cables.
- Telephone cables.
- Traffic signals.
- Traffic signal wiring.
The secondary distribution wiring appears to be a duplex bundle in
which the MGN serves as both neutral and mechanical supporting strand.
A duplex bundle is normally used in situations where only a single
115-volt circuit is required; such circuits are typically provided for
low-capacity loads such as streetlights and traffic signals.
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Joint Pole II
Power, Telephone, CATV, StreetlightThis pole
supports the usual three facilities: electric power, CATV, and telephone.
But note that:
- There is no static wire.
- The MGN is on the same crossarm as the primary conductors.
- The pole includes an unmetered streetlight, wired directly to the
secondary.
- The CATV network is offset on a sidearm probably to maintain
clearances from other facilities.
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caption |
Joint Pole III
Power, Telephone, CATV, StreetlightThis
pole supports:
- A static wire.
- A large transmission line, probably at least 69-Kv.
- Secondary distribution wiring (both open-wire and triplex).
- A streetlight, hardwired directly to secondary distribution.
- CATV cables.
- Two telephone cables, with strand-mounted splice cases.
- A pole-mounted telephone cross-connect panel.
Note that there
is no primary distribution on this pole; the secondary voltage arrives
from a transformer offscreen to the left. |
Joint Pole IV
Power, Alarm Signals, CATV, Telephone, Traffic
SignalsThis pole supports:
- Two primary distribution circuits.
- One open-wire secondary distribution circuit.
- Traffic signal wiring.
- Fire alarm wiring.
- CATV network.
- Seasonal decoration.
- Traffic signals
- Pedestrian walk signals.
Note that the fire-alarm wiring is open wire, and that it appears to be
very close to the CATV cable. If these wires are not insulated,
this would constitute a violation of the National Electrical Safety Code.
When this picture was taken, this pole supported what the National
Electrical Safety Code calls a seasonal decoration. Seasonal
decorations often contain lighting circuits; these circuits are usually
fed from the secondary distribution circuits on the pole. |
Joint Pole V
Power, Transformer, CATV, TelephoneOn this
pole, telephone and CATV cables are mounted side-by-side at the same
vertical position, offset horizontally by a common crossarm. This
arrangement saves space on crowded poles while still maintaining required
clearances. |
Joint Pole VI
Power, Power riser, Streetlight, CATVThis pole
differs from the previous examples in two ways: it's made of prestressed
concrete, and it supports a riser.
Prestressed concrete poles are often used in coastal areas subject to
atmospheric corrosion (one manufacturer claims that "concrete poles are
foremost in appearance, durability and maintenance-free service").
A riser is an electrical connection attached to the side of a
pole; hence, a pole supporting a riser is called a riser pole.
The riser provides a connection between aerial conductors and
underground conductors. The riser conductors are usually protected
by conduit, although a U-guard is sometimes used.
This particular concrete pole supports:
- Static wire.
- A three-phase wye-connected (four-conductor) transmission circuit.
- A three-phase primary distribution circuit, tapped to feed, via the
riser, an underground circuit to a nearby large customer such as a
school, hospital, or shopping center.
- A streetlight.
- A single-phase secondary distribution circuit (fed from a
transformer offscreen to the right) whose sole purpose is to provide
power for the streetlight.
- Strand-supported CATV cable.
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Joint Pole VII
Power, Transformer, CATV, CATV Power
SupplyThis pole supports:
- Three-phase primary electric distribution.
- Transformer.
- Single-phase secondary electric distribution.
- Strand-supported CATV cable.
- Pole-mounted CATV power supply.
- Pole-mounted electric meter to provide power for the CATV power
supply.
CATV networks (also calledbroadband networks) incorporate
broadband amplifiers spaced throughout the network at intervals of
about 2500 feet. These amplifiers require operating power; this
power (at 60, 75, or 90 volts RMS) is provided by a CATV power
supply similar to the one shown here, and delivered to the amplifiers
over the CATV network itself. Each power supply is capable of
powering a group of 10 to 20 amplifiers located within a radius of a mile
or so. Each amplifier incorporates a DC power pack that
rectifies this voltage and provides DC operating voltages for the
amplifier circuitry.
The CATV power supply receives its operating power from the power
company's secondary distribution circuit, at 115 volts, 60 Hz.
Depending on the power company's billing policies, CATV power supplies may
be metered, or they may be billed on a flat-rate basis. The power
supply illustrated here is metered; the meter is visible below the power
supply.
The following sketch illustrates a typical wiring diagram for a metered
CATV (broadband network) power supply:
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Joint Pole VIII
Power, Transformers, CATV, Telephone, Fiber Optic
Cable
This pole supports a separate fiber optic cable in the
communications space. It's probably a voice- and
data-communications cable owned by a telephone company.
The
pole attachment clamp supports the fiber in a padded cylinder so
that wind-induced vibrations do not cause the fiber to scrape
against metal. The red plastic sleeve above the clamp
identifies the name of the owner and provides a contact telephone
number. |
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Farmington, New Mexico,
2004 | |
Joint Pole IX
Power, Telephone, CATV, CATV Power Supplies, Traffic
SignalThis pole supports:
- Three-phase open-wire primary electric distribution.
- Single-phase triplex secondary electric distribution.
- CATV cable for public cable TV network.
- CATV cable for Institutional network ("I-Net"), a closed
circuit coaxial network for schools and municipal government.
- Multipair telephone cable.
- Two CATV power supplies, one for the public CATV network and one for
the I-Net.
- Electric meter (behind the sign) to meter the power used by the two
cable TV power supplies.
- Flashing amber warning light.
- Disconnect switch for the unmetered flashing amber light.
The I-Net is physically identical to the public CATV network (and, in
fact, it was built by, and is probably still owned by, the CATV company).
However, it is connected only to governmental and
quasi-governmental buildings such as City Hall and schools.
There is no electric meter for amber warning light; apparently, the
owner of the light is billed on a flat rate basis.
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