check voltage to these receptacles to ensure they are
de-energized before installing the shore cables.
RIGGING SHORE POWER
The following procedures apply to the shore
installation with a separate circuit breaker or disconnect
for each set of cables and a single, 3-phase receptacle is
not used. You should follow these basic instructions and
procedures before and during connecting to shore
power.
Connect and disconnect shore power under the
direct supervision of the electrical officer, a
qualified leading electrician, and shore-activity
personnel.
Visually inspect shore-power cables for any sign
of defects (such as cracks, bulges, and indications
of overheating), thoroughly examine spliced
cables, in particular, because improperly spliced
cables are extremely dangerous. Strip lug-to-lug
connection splices of insulation and check the
connection for cleanliness, tightness, and good
surface contact. Repair all defects and reinsulate
all lugs before cables are placed in service.
Check cables for insulation resistance using a
500-volt Megger (megohmmeter). Insulation
resistance readings should meet requirements of
Naval Ships Technical Manual, Electric Plant
General, Chapter 300. Check the resistance
between phases and between each phase and
ground. For purposes of the test, shore ground
should be the enclosure that houses shore-power
terminals or receptacles. On ships, ground
should be the hull of the ship or any metal
extension of the hull. During the physical
inspection and Megger tests, check the phase
identification of the cables. Pay particular
attention to cables that have been spliced to
ensure that the phases of the cables are
continuous and have not been altered at the
splices.
Tag with high-voltage signs and, if possible, rope
off the work area surrounding the ships
shore-power terminal box or receptacle. This
box or receptacle is often exposed to elements,
and any moisture present can cause a serious
problem. With the ships shore-power breaker
tagged in the open position, disconnect all
equipment (such as meters and indicator lights)
that could be damaged by a Megger test or cause
a false wading. Test the terminals in the ships
shine-power terminal box or receptacle with a
3-17
voltage tester to ensure they are de-energized
Next, with a 500-volt Megger, test the insulation
resistance between terminals and from each
terminal to ground.
Lay out the cable between the supplying shore-
power outlet and the ships shore-power terminal
box or receptacle. Ensure that the cable is of
sufficient length to allow enough slack for the
rise and fall of the tide, but not of such length as
to permit the cable to dip into the water orbecome
wedged between the ship and pier. Do not permit
cables to rest on sharp or ragged objects, such as
gunwales. Avoid sharp bends. Lay cables in
wood saddles or wrap them in canvas. Raise
splices and connectors from the deck or pier for
protection against water contamination. Neatly
fake out excess cable to minimize damage from
vehicle and pedestrian movements.
Connect the shore cables to the ships
shore-power terminals according to phase or
polarity markings in the box and on the cables.
Ensure correct phase orientation (phase
relationship) by checking color coding or phase
identification markings on cables. Reconfirm
correct phase identification by meggering
between like phases of cables. Cables that give
a zero indication will have the same phase
relationship. After meggering, reconnect any
disconnected equipment.
With a voltmeter, check to ensure that the
shore-power terminals are de-energized.
Connect the shore-power cable to the terminals.
Check for proper phase rotation either by
alternately energizing shore-power receptacles,
one at a time, and observing the ship phase
rotation indicator mounted in the ships service
switchboard or use a portable meter connected
to an appropriate bus. After checking phase
rotation, de-energize each source shore-power
receptacle before energizing the next receptacle
for the phase rotation check.
Energize all source shore-power terminals or
receptacles and proceed with the transfer of
electrical load to shore power following
engineering department operating instructions.
Instructions will vary depending upon whether
or not the ship is equipped to synchronize with
shore power.