FAA Advisory Circular 43.13-1B
Acceptable Methods, Techniques, and Practices
Aircraft Inspection and Repair
AC 43.13-1B | 11. Aircraft Electrical Systems | 12. Wire Insulation and Lacing String Tie | 11-156. Insulation Materials
9/8/98
AC 43.13-1B
SECTION 12. WIRE INSULATION AND LACING STRING TIE
11-155. GENERAL. Insulation of wires
should be appropriately chosen in accordance
with the environmental characteristics of wire
routing areas. Routing of wires with dissimilar
insulation, within the same bundle, is not rec-
ommended, particularly when relative motion
and abrasion between wires having dissimilar
insulation can occur. Soft insulating tubing
(spaghetti) cannot be considered as mechanical
protection against external abrasion of wire;
since at best, it provides only a delaying ac-
tion. Conduit or ducting should be used when
mechanical protection is needed.
11-156. INSULATION MATERIALS. In-
sulating materials should be selected for the
best combination of characteristics in the fol-
lowing categories:
m. Special properties unique to the
aircraft.
n. For a more complete selection of in-
sulated wires refer to SAE AS 4372 Aerospace
Wire Performance Requirement and SAE
AS 4373 Test Methods for Aerospace Wire.
11-157. STRIPPING INSULATION.
Attachment of wire, to connectors or termi-
nals, requires the removal of insulation to ex-
pose the conductors. This practice is com-
monly known as stripping. Stripping may be
accomplished in many ways; however, the
following basic principles should be practiced.
a. Make sure all cutting tools used for
stripping are sharp.
a. Abrasion resistance.
b. Arc resistance (noncarbon tracking).
b. When using special wire stripping
tools, adjust the tool to avoid nicking, cutting,
or otherwise damaging the strands.
c. Corrosion resistance.
d. Cut-through strength.
e. Dielectric strength.
f. Flame resistance.
g. Heat distortion temperature.
h. Impact strength.
i. Mechanical strength.
j. Resistance to fluids.
k. Resistance to notch propagation.
l. Smoke emission.
c. Damage to wires should not exceed the
limits specified in table 11-13.
d. When performing the stripping op-
eration, remove no more insulation than is
necessary.
11-158. LACING AND TIES. Ties, lacing,
and straps are used to secure wire groups or
bundles to provide ease of maintenance, in-
spection, and installation. Braided lacing tape
per MIL-T-43435 is suitable for lacing and
tying wires. In lieu of applying ties, straps
meeting Specification MS17821 or MS17822
may be used in areas where the temperature
does not exceed 120 �C. Straps may not be
used in areas of SWAMP such as wheel wells,
near wing flaps or wing folds. They may not
be used in high vibration areas, where failure
Par 11-155
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