TM 1-1500-204-23-4
j. Conduits. When installing conduits, inspect
using the following procedures:
(1) Ensure the conduit is installed so that
strain and flexing of ferrules is relieved.
(2) Ensure the conduit is not collapsed or
flattened from excessive bending.
(3) Ensure that conduits are installed so that
fluids or condensed moisture will not be trapped.
Suitable drain holes shall be provided at the low points,
except for magneto ground-cable conduit and metallic
flexible conduit.
(4) Ensure that bonding clamps are installed
in such a manner that damage to the conduit cannot
result.
k. Bonds. A bond is any fixed union existing
between two metallic objects that results in electrical
conductivity between them. Such union results from
either physical contact between conductive surfaces of
the objects or from the addition of a firm electrical
connection between them. Inspect for the following
desirable features:
NOTE
Intermittent
electrical
contact
between
conducting
surfaces,
which may become part of a
ground plane or a current path,
shall be prevented either by
bonding, or by insulation, if
bonding is not necessary.
· Metallic conduits shall be bonded
to the aircraft structure at each
terminating and break point. The
bonding path may be through the
equipment at which the conduit
terminates.
· Bond connections shall be secure
and free from corrosion.
· Bonding jumpers shall be installed
in such a manner as not to
interfere in any way with the
operation of movable components
of the aircraft.
· Self-tapping screws shall not be
used for bonding purposes. Only
standard threaded screws or bolts
of appropriate size shall be used.
·
Exposed conducting frames or parts of
electrical or electronic equipment shall
have a low resistance bond of less than
0.1 ohm to structure. If the equipment
design includes a ground terminal or pin
which is internally connected to such
exposed
parts,
a
ground
wire
connection to such a terminal will satisfy
this requirement.
·
Bonding jumpers shall be kept as short
and direct as possible, and when
practicable, shall not exceed 3 inches in
length.
·
Bonds shall be attached directly to the
basic aircraft structure rather than
through other bonded parts insofar as
practical.
·
Bonds shall be installed to ensure that
the structures of military aircraft are
electrically stable and free from the
hazards of lightning, static discharge,
electrical shock, etc., and to provide for
the suppression of radio interference
resulting from these hazards.
l. Junctions. Ensure that only approved devices,
such as solderless type terminals, terminal blocks,
connectors, disconnect splices, permanent splices,
and feed-through bushings are used for cable
junctions. Inspect for the provisions outlined below:
·
Electrical junctions shall be protected
from
short
circuits
resulting
from
movement of personnel, cargo, shell
cases, clips, and other loose or stored
materials. Protection shall be provided
by covering, installing them in junction
boxes, or by locating them in such a
manner that additional protection is not
required.
·
Exposed junctions and busses shall be
protected
with
insulating
materials.
Junctions and busses located within
enclosed
areas
containing
only
electrical and electronic equipment are
not considered exposed.
·
Electrical
junctions
shall
be
mechanically and electrically secure.
They shall not be subject to mechanical
strain or used as a support for insulating
materials, except for insulation on
terminals.
m. Toggle Switches. Inspect toggle switches using
the following procedures:
3-7