Inspection Cables and Wiring Harness Assemblies

TM 750-245-4

CAUTION

Cut the end of nylon straps off flush

with the boss to avoid cuts to hands

from the sharp edges. The plastic

ties may also be used as cable

clamps. Care should be taken that

no cable clamp be placed over a

cable tie.

(9) Service loop (figure 3-28). Where a loop

must be provided to allow opening of an access door,

the harness should be served at the start and end of the

Figure 3-8. Pigtail splice with shield carried

loop. The loop should not be laced, but should be

through.

secured by spot ties or plastic cable ties.

the lacing material around the bundle, over the standing

part, and through the loop.

3-13.

Inspection Cables and Wiring Harness

Assemblies

(4) Single lock stitch (figures 3-21 and 3-22).

The single lock stitch is commonly used for continuous

a. After repair of cable and wiring harness, test for

lacing. It is made by making a single stitch, then

electrical continuity and insulation resistance.

passing the free end under the lacing between the two

b. Visual inspection may be made according to the

stitches and through the loop.

following checklist:

(5) Double lock stitch (figures 3-23 and 3-24).

(1) There shall be no fungus growth, oil,

The double lock stitch is used primarily to prevent lacing

grease, corrosion, or foreign materials (especially

from loosening but is frequently used for complete

around pins and terminals).

lacing. It is made by making two single stitches around

(2) Insulation shall have no cracks, tears,

the bundle and securing with a lock stitch.

cuts, fraying, abrasion, burns, or other deterioration

(6) Spacing of stitches.

The wires in a

throughout entire length with particular emphasis at

finished cable trunk should have a minimum number of

splices and terminations.

crossovers. Crossovers, if necessary, should be at least

(3) Connectors, when required, shall have

8 inches from the termination. Terminating stitches

proper application of potting.

should be made at the end of each lacing. The type of

(4) Terminals and connectors shall not be

stitch is determined mainly by the type of insulation and

twisted, bent, broken, or missing.

diameter of the bundle. The most commonly used stitch

(5) Insulator inserts shall not be burned,

spacing is indicated in table 3-1.

cracked, chipped, broken, or contaminated with any

(7) Serve (figures 3-25 and 3-26). The length

foreign material.

of the serve or endless tie should be equal to

(6) Mounting and connector hardware, dust

approximately the outside diameter of the wire bundle

covers, and caps, shall not be loose, damaged, or

and should not exceed 3/4 inch. To prevent the lacing

missing.

from loosening, it should be served at the point of origin

(7) Identification markings shall not be

and at the point of termination of the lacing. The serve

illegible, incorrect, or missing.

is used at bundle branches or breakouts and at all

bundle end terminations. The serve is made by forming

(8) Color or number code of wire shall be in

a loop along the bundle with the lacing tape, the ends of

accordance with system documentation or have a

the tape toward the bundle end. Wrap the lacing end of

suitable marker indicating correct code on each end.

the tape around the bundle and over the loop. Upon

(9) Pin and socket terminal contacts shall be

reaching the desired length of serve, pass the lacing end

securely seated in connector inserts.

through the loop and pull the ends away from each

(10) Insulator blocks must not be free to be

other. Adjust by pulling until the cross is under the

pulled or pushed out.

serve. Cut this excess tape from each end of the serve.

(11) Minimum radii of bend for power wires

(8) Spot ties (figure 3-27). Spot ties are

and cables shall be 10 x od.

frequently used in place of continuous lacing. They are

(12) Minimum radii of bend for power wires

made exactly like the termination ties.

and cables at terminals or support shall be 3 x od.

(13) Minimum radii of bend for RF cables

enclosed in sleeving shall be 2 x od.

3-5