Condenser Discharge Light System
Periodic maintenance of this system is fairly
simple. Remember, however, that high voltages exist
in the components of the system and you must be extra
careful. One such area is the flash capacitor. This
capacitor may contain as much as 2,000 volts. Anyone
working on the light fixture should make sure that
this capacitor is discharged before working on the
light unit. The capacitor should bleed down through
its resistor network in 5 seconds; however. the
capacitor should be shorted out before any work is
done inside the unit. In a flush unit short between
terminals 7 and 10 ofthe terminal board with a shorting
stick. In the elevated light, short the two contacts on the
left side of the flashtube socket. That must be done
before any work is done inside the light unit, such as
changing a flashtube or cleaning the reflector.
Anyone working on a condenser discharge
light system must make sure that the capacitor
is discharged before working on the light unit.
Since these are sealed units, cleaning the reflectors
rarely should be required. When such cleaning is
required, be sure to use a nonabrasive cleaner. The
lenses in both the elevated and flush units should be
cleaned periodically, depending on the local
Inspect the timer contacts to see that they are clean
and making good contact. If not, the stationary timer
contacts can be adjusted. The timer gears ofthe master
sequence timer require periodic lubrication. Match the
grease to the ambient temperatures expected in your
particular area. NEVER use a graphite-based grease,
as graphite is electrically conductive.Check to see
that both pairs of green indicator lights will light.
When only one lamp is lit on either unit, the other bulb
has burned out. To replace one of these bulbs, remove
the front panel, pull off the colored lens, push out the
old bulb, and insert the new bulb from the front of the
panel. Replace the lens and panel.
Underground Distribution System
Normally speaking, underground systems that are
properly installed require little maintenance of the
routine type. Since both the equipment and the cable
are well protected from man and the elements, the
system normally is not subject to the same problems
that overhead systems experience.
In some areas, groundwater or dampness may
create some problems for underground systems by
increasing rust or corrosion. Racks and splice boxes
may require more painting and other rust or corrosion
maintenance. Look especially for rusted nuts on boxes
and rack hangers. They should be cleaned and painted.
The manholes and vaults should be cleaned. These
areas should not be used for storage or should trash be
allowed to collect in them.
Check the manhole walls for evidence of cracks,
breaks, or other evidence of water seepage or leakage.
Check empty ducts for plugs and evidence of water
You will find manholes with enough water in them
to hamper or prohibit work operations. In such cases,
bail the water out with a bucket and rope or pump it out
with a manhole pump. Sometimes sump holes are built
into the floor of manholes, and these provide places to
bail from or to pump from the lowest places in the
manhole. When water runs into a manhole from
unoccupied ducts, hard rubber plugs are provided to
stop or slow the water. When the manhole pump is used,
place it in a position so the flow of water will be away
from the manhole. That would be on the downhill side.
Place the pump at least 10 feet from the manhole
opening. The pump has a hose to be inserted in the
manhole and an outlet hose to carry the water away from
the manhole. Check cables for proper racking, making
sure that they are trained in the proper direction and
positioned so an ample cable radius is left for bends and
expansion/contraction. This radius is basically 5 to 12
times the cable diameter, depending on the sheath type
and the number of conductors. Make sure that 6 inches
of straight cable exists for racking on each side of the
splice. Check splices for evidence of leakage or
tracking. Look for scrapes, burns, cracks, corrosion, or
any other evidence of cable insulation deterioration. See
that all cables are properly tagged for identification.
Check potheads and terminations that are attached
to risers for leakage, tracking, and evidence of
overheating or an overvoltage. Also, check the security
of the mounting of the pothead and conduit.
Troubleshooting of cable systems is much the
same as any other type of electrical troubleshooting.
You need a thorough knowledge of the system as well
as the ability to analyze problems. A review of the
history ofthe system provides clues to present or future
troubles. Simply using your eyes and head is