could be damaged by a Megger test or cause a false
provided both the ship and shore use these receptacles,
reading. Test the terminals in the ship's shore-power
and the cables are not spliced. Phase orientation need
not be checked prior to hookup. Systems that use
terminal box or receptacle with a voltage tester to ensure
that they are de-energized. Next, with a 500-volt
three-phase receptacles are normally designed so that
interlocks on receptacles automatically trip associated
Megger, test the insulation resistance between terminals
circuit breakers whenever the cover of the receptacle is
and from each terminal to ground.
open, and a shore-power cable plug is not in place.
Lay out the cable between the supplying
However, you should still check voltage to these
shore-power outlet and the ship's shore-power terminal
receptacles to ensure they are de-energized before
box or receptacle. Ensure that the cable is of sufficient
installing the shore cables.
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
RIGGING SHORE POWER
into the water or become wedged between the ship and
pier. Do not permit cables to rest on sharp or ragged
The following procedures apply to the shore
objects, such as gunwales. Avoid sharp bends. Lay
installation that has a separate circuit breaker or
cables in wood saddles or wrap them in canvas. Raise
disconnect for each set of cables and that the single,
splices and connectors from the deck or pier for
three-phase receptacle is not used You should follow
protection against water contamination. Neatly fake out
these basic instructions and procedures prior to and
excess cable to minimize damage from vehicle and
when connecting to shore power:
pedestrian movements.
Connect and disconnect shore power under the
Connect the shore cables to the ship's
direct supervision of the electrical officer, a qualified
shore-power terminals according to phase or polarity
leading electrician, and shore-activity personnel.
markings in the box and on the cables.
Visually inspect shore-power cables for any sign
Ensure correct phase orientation (phase
of defects (such as cracks, bulges, and indications of
relationship) by checking color coding or phase
overheating), thoroughly examine spliced cables, in
identification markings on cables. Reconfirm correct
particular, because improperly spliced cables are
phase identification by meggering between like phases
extremely dangerous. Strip lug-to-lug connection
of cables. Cables that give a zero indication will have
splices of insulation and check the connection for
the same phase relationship. After meggering,
cleanliness, tightness, and good surface contact. Repair
reconnect any disconnected equipment.
all defects and reinsulate all lugs before cables are
placed in service. Check cables for insulation resistance
With a voltmeter, check to ensure that the
using a 500-volt Megger (megohmmeter). Insulation
shore-power terminals are de-energized
resistance readings should meet requirements of Naval
Connect the shore-power cable to the terminals.
Ships' Technical Maunual, "Electric Plant General,"
chapter 300. Check the resistance between phases and
Check for proper phase rotation either by
between each phase and ground. For purposes of the
alternately energizing shore-power receptacles, one at a
test, shore ground should be the enclosure that houses
time, and observing the ship phase rotation indicator
shore-power terminals or receptacles. On ships, ground
mounted in the ship's service switchboard, or use a
should be the hull of the ship or any metal extension of
portable meter connected to an appropriate bus. After
the hull. During the physical inspection and Megger
checking phase rotation, de-energize each source
tests, check the phase identification of the cables. Pay
shore-power receptacle before energizing the next
particular attention to cables that have been spliced to
receptacle for the phase rotation check.
ensure that the phases of the cables are continuous and
Energize all source shore-power terminals or
have not been altered at the splices.
receptacles and proceed with the transfer of electrical
Tag with high-voltage signs and, if possible, rope
load to shore power following engineering department
off the work area surrounding the ship's shore-power
operating instructions. Instructions will vary depending
terminal box or receptacle. This box or receptacle is
upon whether or not the ship is equipped to synchronize
often exposed to elements, and any moisture present can
with shore power.
cause a serious problem. With the ship's shore-power
After cables are carrying the load, inspect all
breaker tagged in the open position, disconnect all
connections to locate any possible overheating resulting
equipment (such as meters and indicator lights) that
3-39
