SUBJECT: APPROVED BY STATUS PURPOSE AFFECTED FUNCTIONS REFERENCES Cable and Harness Making Manager, Hardware Engineering Maintenance Revision Establishes requirements for the fabrication and inspection of cables and harnesses. Requirements of this instruction shall be met by all L-3 Communications Corporation, Division (hereafter referred to as Link) personnel involved in the manufacture of cables and harnesses. Hardware Engineering Manufacturing ASTM-D-4388, Standard Specification for Nonmetallic Semi-conducting and Electrically Insulating Rubber Tapes MIL-R-6855, Rubber, Synthetic, Sheets, Strips, Molded or Extruded Shapes, General Specification for DEFINITIONS Cable assembly. A cable assembly is an assembly of more than one wire, branched if necessary, and terminated with connectors or lugs. A cable assembly normally serves as an electrical interconnection between units (cabinets, cockpit, console, etc.). Cold flow. Distortion of the jacket or insulation on wires caused by sustained pressure. Wiring harness assembly. A wiring harness is a bundle of wires bound as a group by lacing, ties, or similar means. The wiring harness serves as an electrical interconnection between the components, assemblies, drawers, etc., within a unit (cabinet, rack, cockpit, console, panel, etc.). A wiring harness may be: a. Prefabricated and installed as an assembly and identified by a part number. b. Fabricated in place per a wiring list or diagram. This option is at the discretion of Industrial Engineering. 01-26-09 1 of 26 Rev. U
Main trunk. The main trunk is that portion of the assembly which has the largest number of wires. Front face of a connector. The front face of a connector or terminal lug is the mating face of the connector or terminal lug. Examples are as follows: FRONT FACE OF CONNECTOR INSTRUCTION 01-26-09 2 of 26 Rev. U FRONT FACE OF TERMINAL 1. Requirements. The requirements of this instruction are divided into three parts. Cable and harness assemblies. (See paragraph 1.1.) Fabrication of cable assemblies. (See paragraph 1.2.) Harness instructions. (See paragraph 1.3.) 1.1 Cable and harness assemblies. 00110301 a. Splices and ferrules. Except when specified on the engineering drawing, the splicing of wires is only permitted for commercial products. When splices, ferrules, etc., are specified on the drawing, they shall be staggered in the cable or harness in order to prevent buildup of the overall diameter. b. Lacing. Cable assemblies and harnesses shall normally be continuously laced. This instruction, however, provides the option of using spot tying in lieu of continuous lacing when it is considered expedient or more practical. (1) Loose stitching is not permitted. However, stitching must not be so tight as to cause cold flow of the wire insulation. (2) Lacing shall not be used under tubing or sleeving unless specifically noted on the engineering drawing.
(3) Leads shall be separated with a single lockstitch between the black branch and red lines (main body), as indicated on a cable board. (4) Wherever practical, all cable and branch bodies being continuously laced shall be laced with a single strand of braid. Should the braid run short or break, the following procedure shall be followed: (a) (b) (c) Tie off the broken or short end with a double lockstitch, followed by a single lockstitch on two or three wires. (See Figures 4 and 7.) With the new braid, start behind the double lockstitch with a starting stitch. (See Figure 1.) With the running end of the new braid, tie a single lockstitch snug against the double tie-off, then cross over the double tie-off and continue lacing in the normal manner. (5) Continuous lacing. The first tie in continuous lacing shall be a full clove hitch secured with a square knot. (See Figure 1.) (6) Alternate stitches. Alternate stitches or knots, for the first tie, are dependent upon the application. One alternate first tie is used to anchor the cord when lacing in two directions. (See Figure 2.) The other alternative is shown in Figure 3 and is used to anchor one end of the cord to lace a branch. 00110302 00110303 01-26-09 3 of 26 Rev. U
Figure 1 Continuous Lacing First Tie Figure 2 Continuous Lacing Alternate First Tie 00110304 Figure 3 Continuous Lacing Alternate First Tie 00110305 Figure 4 Continuous Lacing Succeeding Ties (Lockstitches) (7) Lockstitches. Succeeding ties in continuous lacing shall be lockstitches. (See Figure 4.) A lockstitch is commonly referred to as a marline. (8) End stitch. The ending stitch shall consist of four lockstitches, two on the last group of leads and two on the longest lead of that group, or, if existing, on the last lead of the branch. (9) Stitch and lacing cord requirements. Table I establishes stitch and lacing cord requirements for cables and harnesses. Table I Stitch and Lacing Cord Requirements for Continuous Lacing CABLE DIAMETER STITCH USED LACING CORD UP to.75 in. (1.9 cm) Single Lockstitch #18-.094 in. (0.239 cm) width (Link PN 244854).75 in. to 1.50 in. (1.9 cm to 3.81 cm) Double Lockstitch #18-.094 in. (0.239 cm) width (Link PN 244854) 1.50 to 2 in. (3.81 cm to 5.08 cm) Double Lockstitch #26-.25 in. (0.635 cm) width (Link PN 281119) (10) Spot ties. Individual spot ties shall be either of two types defined as Option 1 or Option 2. 01-26-09 4 of 26 Rev. U
Option 1: An individual spot tie composed of a full clove hitch secured with a square knot is shown in Figure 5. A minimum of.125 inch (0.318 cm) of lacing cord shall be left after cutting off the ends of the cord. 00110306 Figure 5 Option 1 Spot Tie Option 2: An individual spot tie is executed by drawing both ends of the lacing cord through a type of loop knot (see Figure 6), pulled snug, and secured with a square knot. A minimum of.125 inch (0.318 cm) of lacing cord shall be left after cutting off the ends of the cord. 00110307 Figure 6 Option 2 Spot Tie (11) Lacing and spot tie requirements. Table II establishes spot tie and lacing cord requirements on cables and harnesses. Spacing shall be in accordance with Table VIII. Table II Lacing Spot Tie Requirements CABLE DIAMETER SPOT TIES USED LACING CORD UP to.75 in. (1.9 cm) Single Spot Tie #18-.094 in. (0.239 cm) width (Link PN 244854).75 in. to 1.50 in. (1.9 cm to 3.81 cm) Double Spot Tie #18-.094 in. (0.239 cm) width (Link PN 244854) 1.50 to 2 in. (3.81 cm to 5.08 cm) Double Spot Tie #26-.25 in. (0.635 cm) width (Link PN 281119) (12) Spacing of ties. 01-26-09 5 of 26 Rev. U
(a) (b) See paragraph 1.2a for spacing of stitches and spot ties on cable assemblies. See paragraph 1.3 for spacing of stitches and spot ties on harnesses. (13) Fan lacing. Fans shall be laced approximately 1 to 2 inches (2.54 cm to 5.08 cm) from the point of the fan, as illustrated in Figure 7. The pins or leads in a spares fan shall be numbered to identify each spare. Fan stitching shall start from the point of the fan with a double lockstitch, then a single half hitch (Figure 8) halfway between the branch end and the fan lacing line. At the lacing line, on the first wire (lacing clockwise), there shall be a double half hitch and then a half hitch on each lead thereafter, with a double lockstitch on the final lead of the fan. A minimum of.125 inch (0.318 cm) of cord shall be left. Fan stitching is used only as a manufacturing aid. 01-26-09 6 of 26 Rev. U
8 IN. (20.32 cm) REF (STANDARD FAN LENGTH) 1 IN. to 2 IN. (2.54 cm to 5.08 cm) APPROX. DOUBLE LOCKSTITCH DOUBLE HALF STITCH Figure 7 Fan Lacing 00110308 (14) Half hitch. A half hitch is a stitch formed by making an overhead knot. The only difference between this type of stitch and a lockstitch is that the lockstitch has an extra twist in the loop. (See Figure 8.) Figure 8 Half-Hitch Stitch 00110309 (15) Double half hitch. A double half hitch is two half hitches side by side. 01-26-09 7 of 26 Rev. U
(16) Branch. (a) (b) (c) Double lockstitch. The first lead or group of leads of any branch shall be a double lockstitch. When four or more wires take off from the same body position, they shall be double lockstitched. A double lockstitch is required on all take-off branches at the point it breaks away from a cable body or another branch body. (17) Cross-stitching. When two branch bodies take off opposite each other from the cable body, rigidity may be necessary, and, therefore, cross-stitching is required. If either of the branch bodies are.50 inch (1.27 cm) or larger in diameter, crossstitching is required. (See Figure 9.) If both branch bodies are smaller than.50 inch (1.27 cm) diameter, the cross-stitching is not necessary. DOUBLE LOCKSTITCH ACROSS DOUBLE LOCKSTITCH ON EACH BRANCH CONNECTED THROUGH THE CROSS 00110310 Figure 9 Lacing Branch Leads Opposite Each Other (18) Stitching on radius. A double lockstitch is required on each side of all body pins or hooks when a radius or bend has to be maintained. 01-26-09 8 of 26 Rev. U
(a) (b) (c) (d) When a bend is called for, but is shown as a straight body, a double lockstitch shall be placed on each side of the added allowance (length) as marked on the cable board. The curved position of a harness shall be sewn into the harness only when it is indicated on the harness drawing by a radius. Right angle bends, dimensioned on the harness drawing as such, shall be laced into the harness. All branches, unless otherwise dimensioned on the drawing by a radius or an angle, shall be considered to be at right angles with the main trunk of the cable and shall be laced accordingly. (19) Branch identification. The leads of a branch which terminate at a junction box or a terminal strip shall be laced to indicate the sequence of termination. (See Figure 10.) DOUBLE LOCKSTITCH SINGLE LOCKSTITCH DOUBLE LOCKSTITCH 00110311 Figure 10 Terminations at Junction Box or Terminal Strip 01-26-09 9 of 26 Rev. U
(20) Jumper wires. Double lockstitch all jumper wires with both end take-offs 4 inches (10.16 cm) or less in the main or branch bodies. (21) Connector leads. All leads from a connector to the harness body shall be double lockstitched, starting close enough to the connector to keep the insulation sleeving on the connector contacts in place. (22) Care shall be taken not to subject the wire to abrasions or severe strains which could cause wire breakage or damage to insulation or contribute to cold flow of the insulation when laced. (23) Lacing procedures on large diameter cable/harness. (a) (b) (c) (d) Any cable/harness which exceeds 2 inches (5.08 cm) in diameter shall be split into 2 or more sections. When a number of wires have been run on a cable board to the point where the main trunk of the cable/harness becomes 1.75 inches (4.445 cm) in diameter, cease running wire and lace or bundle the main trunk area at this point. (See Figure 11.) Resume running wire on the cable board until enough has been run to form another 1.75-inch (4.445-cm) section and repeat the lacing process as before until the entire cable/harness is run. Combine all of the trunk sections into one unit trunk, spacing double spot ties of.25 inch (0.635 cm) of lacing cord approximately 10 inches (25.4 cm) apart. (See Figure 12.) (e) At branch points on trunks (See point C, Figure 11), secure the main trunk and the branch trunk with double spot ties within 3 inches (7.62 cm) of the center of the tee. (See Figure 13.) 01-26-09 10 of 26 Rev. U
A C B 10 IN. (25.4 cm) D NOTE: LACE OR BUNDLE AREA A, B, C, D WITH NYLON BRAID IN ACCORDANCE WITH THE REQUIREMENTS OF THIS INSTRUCTION. EACH SECTION INDIVIDUALLY LACED PRIOR TO FINAL TYING. (TO AID IN INSTALLATION OF A CABLE, THE TIES MAY BE RE- MOVED AT A POINT WHERE ADDED FLEXIBILITY IS DESIRED.) 00110313 00110312 Figure 11 Splitting Cable/Harness Figure 12 Combining Split Cable/Harness 3 IN. (7.62 cm) 3 IN. (7.62 cm) 3 IN. (7.62 cm) 00110314 Figure 13 Double Spot Ties of Main Trunk and Branch Trunk c. Nylon tie straps. Spacing of the straps shall be the same as for spot tying. See Table VIII. Table III establishes the cable diameter and the strap requirements. 01-26-09 11 of 26 Rev. U
Table III Nylon Tie Strap Requirements NYLON TIE STRAP CABLE DIAMETER PART NUMBER WIDTH LENGTH INCHES (cm) INCHES (cm) INCHES (cm) Up to.625 (1.588 cm) MS3367-4-9.100 (0.254 cm) 2.72 (6.909 cm).625 to 1.125 (1.588 to 2.858 cm) MS3367-5-9.146 (0.371 cm) 4.68 (11.887 cm) 1.125 or 1.75 (2.858 to 4.445 cm) MS3367-1-9.190 (0.483 cm) 6.30 (16.002 cm) 1.75 to 4 (4.445 to 10.16 cm) MS3367-2-9.192 (0.488 cm) 13.35 (33.909 cm) (1) Tool adjustment. The tie strap tool shall be adjusted to result in a snug, fully locked installation. The tool shall cut off the surplus strap tail approximately flush with the boss of the strap. (2) Branch points. At branch points on cables, a strap shall be used before and after the take-off points and on the branch itself adjacent to the take-off point (Figure 14, part A). (a) The use of a single strap, cross-wrapped as in Figure 14, part B is optional where the diameter of the branch does not exceed.50 inch (1.27 cm). A. B. 00110315 Figure 14 Tie Straps on Branch Points 01-26-09 12 of 26 Rev. U
(b) At the branch points on cables, where the spacing is 1 inch (2.54 cm) apart, the straps shall be applied (as shown in Figure 15), with one strap between the branches serving as the following tie for the second branch. The single cross-strap as shown at the right branch in Figure 15 is optional. 1 IN. (2.54 cm) 00110316 Figure 15 Tie Straps on Branch Points 1 Inch (2.54 cm) Apart (c) On cables which have branch leads opposite each other, and the branches are less than.50-inch (1.27-cm) diameter, straps shall be applied as shown in Figure 16, part A or B. If either branch is greater than.50 inch (1.27 cm) diameter, separate branch ties and cross-straps are required as in Figure 16, part C. 01-26-09 13 of 26 Rev. U
A. B. C. Figure 16 Tie Straps on Branch Points Opposite Each Other 00110317 (3) Whenever the mounting boss-type of tie strap is called out on a cable assembly for a specific application, the boss shall be installed at the top of the trunk, unless otherwise specified. (See Figure 17.) 00110318 Figure 17 Location of Mounting Boss Type Tie Strap d. Zipper tubing/expandable braided sleeving. 01-26-09 14 of 26 Rev. U
(1) Shielded zipper tubing, such as Link PN 454086 through 454095, contains an internal overlap of metallic shielding that must completely surround the cable conductors in order to provide efficient radio frequency and ultra-high frequency shielding of the cable assembly. When used, care must be taken to insure that the shield overlap is not folded back or under and that all conductors are enclosed within the shielding. The overlap of the zipper tubing shall be sealed when completed. (See Figure 18.) SHIELD OVERLAP ZIPPER TUBING CABLE CONDUCTORS 00110319 Figure 18 Shielded Zipper Tubing Internal Overlap (2) When a drawing specifies the grounding of the shield of shielded zipper tubing to the shell of a connector, trim back the zipper tube insulation at the shell, leaving approximately 2 inches (5.08 cm) of the.25 inch (0.635 cm) braid exposed. Fold the braid back over the zipper tubing and under the cable clamp. Install a lug on the braid and place the lug under the screw of the cable clamp. An identification sleeve is required on the ground braid. (3) Unless otherwise specified on the drawing, the method to continually shield branched legs will be as follows. Each zipper tubing shield will terminate as close as possible to the junction point. A cable tie or lacing cord will be used to terminate the insulation. Unless otherwise specified, all shields shall be made common by soldering. (See Figure 19.) 01-26-09 15 of 26 Rev. U
SOLDER CONNECTION SHIELD 00110320 Figure 19 Terminating Continual Branch Shields of Shielded Zipper Tubing (4) Plain, unshielded zipper tubing may be spliced by closing and spot tying the end of one of the tubing sections in two places, inserting it into the second section, closing the second section and again spot tying in two places. (See Figure 20.) The maximum number of splices in a cable or harness assembly shall be in accordance with Table IV. Table IV Splices Permitted For Unshielded Zipper Tubing CABLE LENGTH MAXIMUM NO. OF SPLICES Less than 10 ft (3.048 m) 0 10 ft to 25 ft (3.048 m to 7.62 m) 1 Over 25 ft (7.62 m) 2 2.0 to 4.0 In. (5.08 cm to 10.16 cm) depending on tubing diameter. Figure 20 Splicing Unshielded Zipper Tubing 00110321 01-26-09 16 of 26 Rev. U
(5) Shielded zipper tubing may be spliced by trimming the section ends similar to those shown in Figure 21, overlapping and soldering the metal braid, and spot tying the two sections in two places after closing. Dimensions in inches (centimeters) in Figure 21 are approximate. Maximum number of splices per cable or harness assembly shall be as specified in paragraph 1.1d(4). TRIM SHIELDING AND INNER LINER TO POINT WHERE INNER LINER IS BONDED TO TUBING BRAID END B BRAID SOLDERED TO END A BRAID, FAR SIDE, FULL LENGTH OF OVERLAP KEEP GAP TO A MINIMUM END A 1.25 IN. (3.175 cm) END B END A END B.25 IN. (0.635 cm) 2.0 TO 4.0 IN. (5.08 cm TO 10.16 cm) DEPENDING ON DIAMETER CLOSE AND SPOT TIE BOTH ENDS AS SHOWN 00110322 Figure 21 Splicing Shielded Zipper Tubing (6) Except at branch points, when zipper tubing/expandable braided sleeving is used, the cable shall not be laced or tie straps used at any point covered by the zipper tubing/expandable braided sleeving. (7) When zipper tubing or expandable braided sleeving is specified, it shall be applied to all branch and cable lengths 6 inches (15.24 cm) or longer. Table V defines the cable diameters and corresponding requirements. The next size larger or smaller of the applicable tubing/sleeving may be used. The same basic item as specified on the Engineering drawing shall be used, the substitution being limited to variations in tubing/sleeving diameter. (a) Expandable braided sleeving. When using expandable sleeving on the main body of cables, single wire 01-26-09 17 of 26 Rev. U
branches may be pulled through the sleeving with a hook-type instrument. A spot tie or tie strap shall be applied (as specified on the drawing) on each side of the branch over the sleeving. (b) Cutting expandable sleeving. To eliminate fraying, expandable sleeving shall only be cut with a hot knife. Table V Zipper Tubing, Expandable Braided Sleeving Requirements CABLE DIAMETER ZIPPER TUBING LINK PN ZIPPER TUBING ID EXPANDABLE BRAIDED SLEEVING LINK PN ID BRAID SLEEVING UP to.250 (0.635) 1005478-024.375 (0.953) 1007010-004.25 (0.35).250 to.375 (0.635 to 0.953) 1005478-025.500 (1.27) 1007010-001.50 (1.27).375 to.500 (0.953 to 1.27) 1005478-026.625 (1.588) 1007010-001.50 (1.27).500 to.625 (1.27 to 1.588) 1005478-027.750 (1.905) 1007010-005.75 (1.905).625 to.750 (1.588 to 1.905) 1005478-028.875 (2.223) 1007010-005.75 (1.905).750 to.875 (1.905 to 2.223) 1005478-029 1.000 (2.54) 1007010-005.75 (1.905).875 to 1.125 (2.223 to 2.858) 1005478-031 1.250 (3.175) 1007010-002 1.25 (3.175) 1.125 to 1.375 (2.858 to 3.493) 1005478-033 1.500 (3.81) 1007010-002 1.25 (3.175) 1.375 to 1.625 (3.493 to 4.128) 1005478-035 1.750 (4.445) 1007010-003 2.5 (6.35) 1.625 to 1.875 (4.128 to 4.763) 1005478-036 2.000 (5.08) 1007010-003 2.5 (6.35) NOTE: All dimensions are in inches (centimeters). e. Small diameter cable. When the diameter of a cable or harness is too small for a connector clamp, and a grommet or filler is not specified, the clamp may be filled by wrapping the cable or harness with a sufficient number of turns of solid rubber strip (such as Link PN 263022) to provide a good clamping action. (Reference paragraph 1.2c.) f. Large diameter cables. When the engineering drawing specifies a cable clamp rubber grommet and the diameter of the cable or harness is too large to assemble the grommet under the clamp, the grommet may be omitted. However, if omission of the grommet creates a loose clamping condition, the clamp may be filled as specified in paragraph 1.2c. g. Wire braid, shielding. In order to better utilize materials, it is permissible to splice wire braid when used as shielding in a cable or harness assembly. Splicing shall be accomplished by overlapping the two ends by 1 or 2 inches (2.54 cm or 5.08 cm), depending on the braid diameter and soldering the complete length and circumference of the 01-26-09 18 of 26 Rev. U
overlapped portion. The maximum number of splices in a cable or harness assembly shall be in accordance with Table VI. Table VI Splicing Requirements For Wire Braid Shielding CABLE LENGTH MAXIMUM NUMBER OF SPLICES Less than 10 ft (3.048 m) 0 10 ft to 25 ft (3.048 m to 7.62 m) 1 Over 25 ft (7.62 m) 2 h. Flexible, plastic-covered metal conduit. (1) Flexible, plastic-covered metal conduit, similar to Link PN 1002052, may be spliced by use of two box connectors (Link drawing No. GN88048) and one rigid conduit nipple (Link drawing No. 1002631). Refer to the referenced drawings for complete part (dash) numbers of the various sizes. The maximum number of splices per cable assembly shall be in accordance with Table VII. Table VII Splices Permitted For Flexible, Plastic-Covered Metal Conduit CABLE LENGTH MAXIMUM NUMBER OF SPLICES Less than 10 ft (3.048 m) 0 10 ft to 25 ft (3.048 m to 7.62 m) 1 Over 25 ft (7.62 m) 2 (2) Conduit splicing. Box connectors come complete with a compression nut, ferrule, and connector body. Use of these conduit connectors is shown below. (a) (b) (c) Cut conduit to the desired length, making certain that the neoprene jacket and conduit are flush, and place compression nut over conduit. (See Figure 22.) Screw ferrule into the spiralled steel liner wall of the conduit. (See Figure 23.) Place the conduit with the ferrule into the connector body and tighten the compression nut as far as it will go, so that it touches the connector body stop. (See 01-26-09 19 of 26 Rev. U
Figure 24.) This will assure correct collaring of the conduit so that the end of the ferrule pinches around the conduit, forcing the metal edge of the ferrule to curve out slightly. (See Figure 25.) CONDUIT CUT FLUSH CONDUIT COMPRESSION NUT FERRULE CONNECTOR BODY 00110323 COMPRESSION NUT FERRULE 00110324 Figure 22 Splicing Conduit Figure 23 Splicing Conduit COMPRESSION NUT CONNECTOR BODY 00110325 COMPRESSED FERRULE 00110326 Figure 24 Splicing Conduit (d) Figure 25 Splicing Conduit Assemble the two conduit ends with assembled box connectors into the conduit nipple, completing the splice. (See Figure 26.) CONDUIT NIPPLE 00110327 Figure 26 Splicing Conduit i. Spare wires. Spare wires shall be handled in accordance with the following: (1) Prejacketed cables. When the drawing specifies spare wires run to a connector but not terminated in connector pins, the wires shall be the same length as the connected wires and shall be spot tied to the cable. 01-26-09 20 of 26 Rev. U
(2) Nonprejacketed cables. When the drawing specifies spare wires run to a connector but not terminated in connector pins, the spare wires shall be a minimum of 6 inches (15.24cm) longer than the connector wires. The spare wires shall be looped back inside or outside the cable tubing or sheathing. When looped back outside, the wires shall be spot tied to the cable as shown in Figure 27. Each spare wire shall be tied in a single overhand knot at the end of the wire to prevent loss of the identification sleeve. (See Figure 27.) P1 LACING LACING P2 SPARE WIRES IDENT SLEEVES SPARE WIRES IDENT SLEEVES 00110328 Figure 27 Spares in Nonprejacketed Cables (3) When the drawing specifies short lengths of spare wires to be terminated in a connector, the spare wires shall be looped back and tied to the cable in a manner similar to that shown in Figure 28. Each such spare wire shall be tied in a single overhand knot at the end of the wire to prevent loss of the identification sleeve. (See Figure 28.) (4) NC (No Connection) wires shall be handled in the same manner as spare wires. P1 LACING P2 SPARE WIRES IDENT SLEEVES 00110329 Figure 28 Short Lengths of Spares Terminated in Connector 01-26-09 21 of 26 Rev. U
j. Wiring list. The manufacturing departments shall make a wiring list for each cable board fabricated in their respective departments if a wiring list does not exist. The wiring list shall be kept on file in the department fabricating the cable board. k. Harness fabricating procedures. (1) Check the Bill of Material block on the cable or harness board for wire part number, gauge, and color of wire. Check the Engineering Change Notice Number on the board to see if it agrees with the change number on the Harness Assembly drawings. If there is no assembly drawing, then the board should be checked against the Schematic Diagram or the Schematic List. (2) The drawings, wire list, and plug sheets (Schematic List) are to be followed at all times. No deviation will be allowed unless the drawings are marked and stamped with an approved change control stamp and signature, or the change is included on an ECN against the affected drawing. (3) If the wiring list does not agree with the best running sequence, a change should be suggested to the industrial engineer. (4) Visually inspect the cable or harness board for bent pins, bent hooks, or any other defects which could change the physical dimension of the harness. (5) The wire shall be run on the board in accordance with the wire list. Usually the largest gauge wire is run first, followed by twisted pairs, if any, then completed by running the small-gauge wires. (6) Wires are not to be run on the board so tightly that it may cause wire breakage, or damage to insulation or contribute to cold flow of the insulation when lacing. (7) All wires are to be run within the body guide lines and pins so that wires will lie in the correct channels. 01-26-09 22 of 26 Rev. U
(8) When terminating a wire on a given pin, it is to be cut. Terminating the wire by snapping is not permitted. (9) Lead wires shall be run to the correct connection pin via the position pin as indicated on the harness drawings and harness board. (10) After the last wire is run on the board, physically check the wire terminations against the schematic list in order to make sure all wires called out have been run on the board. 1.2 Fabrication of cable assemblies. a. Spacing of stitches (continuous lacing) and spot ties (when used in lieu of continuous lacing) on cable assemblies shall be in accordance with Table VIII. Table VIII Spacing of Lacing Stitches CABLE DIAMETER Up to.50 in. (1.27 cm) Over.50 in. (1.27 cm) SPACING 3 in. (2.62 cm) ±.50 in. (1.27 cm) 4 in. (10.16 cm) ±.50 in. (1.27 cm) 01-26-09 23 of 26 Rev. U
b. Cable and harness length dimensions, as specified on the assembly drawings, shall be interpreted as dimensions to the front face of the connector(s), terminal lug(s), or termination(s). Dimensions for branch lengths shall be from the branch side at the take-off point to the face of the connector. Tolerances on cable lengths, unless otherwise specified on the drawing, shall be in accordance with Table IX. Table IX Cable and Harness Tolerances LENGTH * UP to 6.0 IN. (15.24 cm) OVER 6.0 IN. to 36.0 IN (15.24 cm to 0.914 m) OVER 36.0 IN. to 60.0 IN. (0.914 m to 1.524 m) OVER 5.0 FT to 10.0 FT (1.524 m to 3.048 m) TOLERANCE +1.0 IN. (2.54 cm) - 0 +2.0 IN. (5.08 cm) - 0 +4.0 IN. (10.16 cm) - 0 +6.0 IN. (15.24 cm) - 0 OVER 10.0 FT to 50.0 FT (3.048 m to 15.24 m) +2 FT (0.6096 m) - 0 OVER 50.0 FT to 75 FT (15.24 m to 22.86 m) +3 FT (0.9144 m) - 0 OVER 75.0 FT (22.86 m) +4 FT (1.219 m) - 0 * Exception. Twisted-pair, flat-ribbon cable. Proper termination of twisted-pair ribbon cable, such as Link PN 1005857, requires that the connector be applied only on flat surfaces of the cable at increments of 20 inches (50.8 cm). If the assembly drawing requires a length that does not coincide with a flat surface, the overall length shall be increased to the next flat surface in the ribbon cable. c. Due to the inflexibility of some types of special purpose electrical multiconductor cable, it is permissible to strip the outer jacket a maximum of 4 inches (10.16 cm) to facilitate wiring the connector. After wiring the connector, it is necessary to protect the conductors and provide adequate strain relief under the connector clamp. Strain relief is accomplished using one of the following methods: (1) The preferred method is to wrap a strip of rubber sheet or linerless rubber splicing tape around the exposed conductors. The rubber cushion shall be of the appropriate width and length according to the cable size and clamp size. The cushion is made from MIL-R-6855 synthetic rubber sheet or splicing tape wrapped to a.062 inches thickness. (See Figure 29.) The 01-26-09 24 of 26 Rev. U
synthetic rubber shall comply with the requirements of ASTM- D-4388 or MIL-R-6855. (2) Heat shrink tubing shall be placed over the exposed conductors. (3) Wire braid shall be doubled back and laced over the exposed conductors. (4) Rubber grommets shall be used only when specified on the drawing. NOTE: NOTE: Electrical tape and pressure-sensitive adhesive identification tape (reference LMS 11-8) shall not be used for strain under any condition. Conductors shall be firmly secured within the strain relief when the clamp is tightened. STRAIN RELIEF CLAMP ADD RUBBER SHEET CUSHION CONNECTOR CABLE OUTER JACKET 4.0 IN. (10.16 cm) MAX. Figure 29 Rubber Sheet Cushion Under Strain Relief 01-26-09 25 of 26 Rev. U 00110330 d. When the drawing specifies multiconductor cable utilizing splices, the outer jacket may be stripped more than 4 inches (10.16 cm), provided an abrasive protective sleeving is used to replace the outer jacket that was removed. 1.3 Harness instructions. The spacing of stitches (continuous lacing) and spot ties (when used in lieu of continuous lacing) shall be approximately one inch (2.54 cm) apart on small harness wiring such as card bins and relay chassis, and approximately two inches (5.08 cm) apart on cabinet and unit harness wiring.
1.4 Other applications. a. Applicable portions of this instruction shall be utilized in the fabrication of panel assemblies and units which require the application of lacing, protective coverings such as zipper tubing, identification sleeves, and/or dangle connectors. Spacing of stitches shall conform to paragraph 1.3. Tolerances for length of wire/bundle branches, which terminate in dangle connectors or crimp-type terminations, shall conform to paragraph 1.2b. b. All dangle connectors shall be protected in accordance with paragraph 1.5. 1.5 Protective measures. All unmated connectors shall be suitably protected from contamination (e.g., dirt, dust, moisture, etc.) during maintenance, storage, and shipment. Connectors on enclosed cabinet mounted equipment are not required to be protected unless an environmental hazard exists. 2. Quality Assurance Requirements 2.1 The Quality Assurance Organization shall be responsible for assuring that the workmanship meets the minimum requirements specified herein. 2.2 Inspection shall be conducted to assure that all cables and harnesses meet the requirements of this Manufacturing Standard, the applicable engineering drawings, and associated documents. 3. Preparation For Delivery. (Not Applicable) 01-26-09 26 of 26 Rev. U