TM 5-684/NAVFAC MO-2OO/AFJMAN 32-1082
that the cable can be picked up at any desired point
is reached where moisture is no longer present in
for repair or inspection. Maps should indicate the
exact location of the cable at various points along its
a. Replacement of cable section. The cable section
length, as established by measurements with sur-
which has been removed should be replaced by
veying instruments. Maps should also indicate the
splicing in a new cable of sufficient length. The
exact length of cable installed between any two ref-
cable manufacturer's splicing kit instructions
erence points, so that any movement or drifting of
should be followed for making splices which will
the cable on the bottom can be estimated.
probably have to be made on a boat or barge. Care
should be taken not be bend the cable sharply
5-21. Cable repair safety.
where it enters the water or where it rests on the
bottom. When the cable is again laid in the water,
Cable repair will involve: working with other cables
the top must be carried out and laid down in such
which may or may not be energized; ensuring that
manner that there will be no sharp kinks or bends
the grounds and bonds essential for safe operation
in the cable.
are in good condition; and, in some cases, dealing
b. Protection of submarine cables. Because sub-
with hazardous substances.
a. Energized cables. Repair work on electric
marine cable is relatively unprotected as it lies on
the bottom of a body of water, special precautions
cables should be done unenergized. However, other
must be taken to prevent damage from swift cur-
cables in the manhole may be energized and inspec-
rents, boat anchors, or other causes. Normally,
tions will usually be done with cables energized.
these precautions are taken during the original
Moving cables while energized should be restricted
cable installation and are not the concern of repair
to low-voltage cables in good condition and with
and maintenance personnel. The following para-
adequate bending radii. When the condition of any
graphs describe steps to be taken if original precau-
insulation is questionable, or cables are installed to
tions were omitted, or if original precautions were
their permissible bending radius limits, a small
disturbed in the process of cable repair.
change in radius to an energized cable could cause a
(1) Anchors. When a cable crossing is subjected
b. Grounding and bonding. Inspection and main-
required to prevent excessive drifting of shifting of
tenance of cable grounds are as important as the
the cable along the bottom. These anchors are usu-
inspection and maintenance of cables, both for
ally made fast by a series of U-bolts which pass
safety and for corrosion mitigation. Ground rods
through a common base plate, thus affording a mul-
should also be inspected.
tiple grip of the cable. Other U-bolts, eyebolts, or
c. Hazardous substances. Hazardous substances,
alternate means are usually provided for attach-
such as lead or asbestos, should be replaced when
ment of the anchor cable or chain. Ordinarily, the
the cable repair work requires their removal; such
anchors are masses of concrete sufficiently large to
as pulling new cable in ducts sealed with lead or
resist the draw of the current. When the water is
asbestos or splicing cables having asbestos fire-
shallow, anchors may be placed on the cable as it is
proofing. Encapsulating materials are available
being reeled out. When a deep-water crossing is
which will prevent asbestos fibers from becoming
encountered, attachment of the anchors to their
airborne. See chapter 15, section II.
chains must be done by a diver.
5-22. Making cable repairs.
(2) Warning signs. Suitable warning signs indi-
cating the location of the shore ends of a submarine
In many cases, the fault will be in either an existing
cable, and stating that anchoring of vessels is pro-
splice or a termination, and the repair is compara-
hibited in the immediate vicinity of the cable any-
tively simple. In other cases, the fault will be in the
where along its length, are required for every sub-
cable itself, and the repair involves removing a de-
marine cable crossing.
fective cable length and splicing in a good length.
(3) Pile clusters. Clusters of piles are fre-
The replacement must be the same as the original
quently driven at the shore lines of important cables
cable or a type of cable comparable to and compat-
where they enter and leave the water. These aid in
ible with the original cable. Splice kits and termina-
locating the points where the cable is anchored. Pile
tion kits should be used as much as possible. The
clusters also provide a certain amount of mechani-
following paragraphs contain general instructions
cal protection for the cables and furnish platforms
for the various types of cables. More detailed in-
on which to mount warning signs.
structions are given by the manufacturers of the
cable and splice kits used for any specific job. After
(4) Maps. The development of accurate maps is
the repair is completed (and before backfilling for
one of the most important tools in maintenance and
direct-burial cable) insulation resistance and poten-
repair of a submarine cable installation. It ensures