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After cleaning, but before grounding hardware installation, cleaned surfaces shall be protected with a corrosion resistant conductive protective film in accordance with AMS-C Class III. After hardware assembly, the mating surfaces around the ground hardware shall be restored to the original finish, or if subject to fuel exposure, shall be sealed with a compound in accordance with environmental requirements of the area.

All threaded hardware connections shall utilize a split lockwasher with either plain or self-locking hardware to ensure a tight connection under all conditions. Cadmium plated hardware shall not be used in space applications. Self-tapping screws, zinc plated, unplated and anodized hardware, shall not be used.

Internal or external tooth lockwashers shall not be used. Bonding jumpers shall be the non-quick disconnect type and shall be in accordance with MS or contractor designed equivalent. Use of conduit requires procuring activity approval unless specifically required elsewhere in this specification. Metallic conduit may be used for shielding to meet the requirements of MIL-STD, subject to approval by the procuring activity. Polyvinyl chloride shall not be used. In determining the diameter of conduit to be used, the wiring which is to be installed therein shall be bundled together and the maximum diameter measured.

Nonmetallic conduit shall be terminated with approved AN or MS fittings. Rigid metallic and nonmetallic conduit used for wiring inaccessible areas need not be terminated provided the conduit is suitably flared or rounded and sharp edges removed. Suitable drainage holes shall be provided at the low points, except for magneto ground cable conduit and metallic flexible conduit.

Tape nonadhesive used as a wrap around wiring shall also have drainage holes at the low points. Burrs shall be removed from drainage holes in metallic conduit and from the conduit fittings. The bonding path may be through the equipment at which the conduit terminates. Bonding connections to the conduit shall be made with an AS clamp and a bonding jumper, with one terminal secured to the clamp with threaded fasteners.

Surfaces between clamp and conduit and between terminal lug and clamp tab shall be prepared to insure a suitable low-resistance bond. After cleaning, but before clamp installation, aluminum conduit surfaces shall be conductive conversion coated in accordance with AMS-C After bonding hardware assembly, mating surfaces around the ground hardware shall be restored to the original finish or, if subject to fuel exposure, shall be sealed with a compound in accordance with AMS-S Conduit and conduit fitting bends shall not cause chafing of the wiring.

When using special contacts such as thermocouple or coaxial, circular electrical connectors shall be specified on installation drawings using the A and B suffix when applicable in the connector part number. The selection and use of connectors for fiber optics cable shall be approved by the procuring activity.

The connectors shall have an interfacial seal as well as sealing at wire ends. Environment resisting connectors having wire sealing grommets are preferred; however, potting may be used where a grommet seal connector would not be suitable see 3. The outside diameter of the wiring terminated at the connector that has a wire sealing grommet shall comply with the wire diameter range specified for that connector see 3.

Contacts shall be in accordance with AS or the applicable connector specification. Wire size shall be within crimp barrel size range as specified in contact specification.

Wire barrel contact bushings, in accordance with AS, shall be used when crimping some wire sizes in size 0, 4 and 8 contacts. Contractors may use automatic, semi-automatic, or hand crimp tools for production. Contractors will only specify MIL-DTL tools for the tools specified in the component specification or contract replacement. MS or applicable sealing plugs shall be inserted in unused grommet holes of environment resistant connectors.

Sealing plugs shall not be installed where they interfere with the free movement of the spring loaded socket termini on connectors containing fiber optic termini. For potted connectors, each spare contact shall have a pigtail attached, consisting of a wire of the largest size that can be accommodated by the contact and extends 5 to 7 inches beyond the potting material.

The pigtails shall be identified and dead-ended. In firewall applications there shall be no spare contacts. All unused contact cavities shall be wired. Stub wires shall be capped with polytetrafluoroethylene insulated dead-end cap.

Connectors with fiber optic pin termini, whose mating connector have the alignament sleeves built-in, must use special contacts with a shorter pins to preclude damage to the mating termini. Where it is necessary to maintain electrical continuity for a limited time under continuous flame, both the receptacle and mating plug shall be fireproof. If only flame integrity is necessary without the need for electrical continuity, only the receptacle needs to be fire-proof.

Fireproof and firewall connectors shall meet the Class K, KT or KS requirements of the applicable military specification. Category B connectors of this specification shall be used only on original equipment. When using Category B connectors, the contractor shall specify an equivalent field replaceable connector as defined on the latest issue of MIL-PRF for replacement as a maintenance or repair item.

Category B connectors are not recommended for maintenance or repair. Category E and F connectors of this specification shall be used for applications using semi-rigid coaxial cables. Where connector parameters beyond the scope of the military specification are required, nonstandard commercial types may be utilized provided that they meet the general requirements of the applicable military specification and are approved by the procuring activity.

Connectors shall be located and installed so that they will not provide hand holds or foot rests to operating and maintenance personnel, or be damaged by cargo and stored material.

Receptacles in pressurized structure shall preferably be installed with the flange to the high pressure side. Fasteners shall be used in all holes of flange mouned connectors. At least one inch shall be provided around the coupling rings of circular connectors, unless size of the equipment or area available for connector installation, and the number and size of the connectors prohibit this spacing.

Where connectors can be sequentially mated and unmated a 1-inch clearance in a swept area of at least degrees around the connector at the start of the removal and replacement sequence shall be provided. Airframe connectors, when installed with the axis in a horizontal direction, shall be positioned so that the master keyway is located to the top. When the connector axis is vertical, the master keyway shall be positioned to the front of the vehicle.

Both plug and receptacle shall be visible for engagement and orientation of the polarizing key s. Rectangular connectors may be mounted in close proximity, or stacked, provided that each one can be mated or unmated without first unmating adjacent connectors.

Access for tools during mating or unmating is required. For volt DC external power receptacles, a means shall be provided to eliminate potential arcing by automatically shutting off ground power before the electrical separation of power pins and sockets can occur. The receptacle shall not be located in or near hazardous areas such as air inlets or exhausts, auxiliary power unit or jet fuel starter exhaust, propellers or propeller blasts, or fuel servicing or vent areas.

The external power receptacles shall be accessible from ground level. The receptacle shall not be located more than 6 feet above the bottom of the air vehicle wheels. At no time shall there be more than 10 feet of cable hanging unsupported from the receptacle.

The receptacle shall be located in a position such that the plug will fully mate with the receptacle without the plug being modified. The external power plug shall be in accordance with AS The external power receptacles shall be protected from dirt, fluids, and other contaminants when it is not in use. The receptacle shall be prominently identified to facilitate air vehicle servicing.

The receptacle location shall take into consideration the ease of repair and replacement. It is preferred that wiring be routed and supported such that an improper connection cannot be made. The order of precedence for making the connector selection for a multiple connector location shall be as follows: a.

First, the connectors shall be different sizes or have different insert arrangements. Second, the connectors with the same insert arrangements shall have alternate insert positions or keying positions. Third, if none of the above requirements can be met, identical connectors shall have color coded sleeves attached to the wiring near the connector which identifies the associated connector mating half.

In cases where one of the connectors is mounted, the connector shall be coded by a color identifier on the adjacent structure. Connectors installed external to the vehicle proper, such as in engine compartments, wheel wells, etc.

Connectors shall not be mounted or located in a position where they will support standing water. When safety wiring is required on electrical connectors or connector accessories which use threaded coupling rings, or on plugs which employ screws or rings to fasten the individual parts of the plug together, the components shall be safety wired in accordance with NASM using 0.

Safety wire may also be installed in accordance with AS using 0. For higher temperatures, potting shall not be used unless specifically approved by the procuring activity. If protective sleeving, identification sleeves, jacketing or braiding is terminated at a potted connector, it shall not extend into the potted material. Insulated sleeving shall not be used within the potted material of the connector. For Air Force procurement, all potting of connectors is discouraged and requires specific application approval.

Unmated connectors containing fiber optic termini shall be protected from dust and contamination. The dummy receptacle shall be conspicuously marked and conveniently located to accommodate the unmated connector or protective cover. The dummy receptacle shall conform to the requirements of the related connector specification. Accessories shall not be used to terminate ground wires or shields unless the accessory was specifically designed to terminate ground wires or shields.

Ground wires shall not be terminated to saddle clamp screws. Fiber optic connectors shall be provided with strain relief in accordance with the individual connector specifications.

NOTE: When flexible conduit is used, additional strain relief is not required. Only approved devices, such as permanent splices, feed-thru bushings, terminal boards, terminal junction systems and connectors, shall be used for wire junctions. The need and choice of junctions shall be determined by consideration of reliability factors, maintenance factors and manufacturing procedures, in that order of selection.

Solderless junctions are preferred. The use of solder junctions shall be kept to a minimum. They shall not be subject to mechanical strain or used to support insulating materials, except for insulation on terminals and splices. Junctions shall not depend upon insulators under compression for maintaining the connection tightness. Circuit continuity shall not depend upon nonmetallic parts retaining original shape when subjected to compression loading. Wires and filter line cables shall be stripped in accordance with AS Wire stripping tools shall be inspected in accordance with AS When the stripped portion of the conductor is visible in the crimp contact inspection hole, no more than 0.

These dimensions shall be applicable for contacts, terminal lugs and splices. For terminal lugs, the stripped portion of the conductor shall extend to a point beyond the open end of the crimp barrel, which will not interfere with the stud, washer, nut or similar attachment device. For splices, the stripped portion of the conductor shall be visible in the inspection window.

The wires shall fit into the diameters of the insulation support without altering their insulation. The resistance of other junctions shall not exceed the maximum resistance allowed by the specification for that device. Suitable insulating barrier material may be used to provide necessary creepage distance.

This protection may be provided by covering the junctions, by installing them in junction boxes, by locating them in such manner that additional protection is not required, or by other means acceptable to the procuring activity.

Reusable devices are preferred to nonreusable material. Junctions and buses located within enclosed areas containing only electrical and electronic equipment are not considered as exposed. Compartments housing electrical and electronic equipment but which are naturally adaptable as stowage areas or which are not protected against occasional debris, etc. Terminal junctions located in wheel wells shall be protected against the effects of water thrown by the wheels.

These junctions shall be individually encased with insulating material to insure electrical insulation and isolation from foreign material. This shall include those junctions that are installed for manufacturing convenience. They shall be installed in such a manner that mechanical movements are free from interference, that fasteners are unable to cause short circuits, and that proper drainage is provided.

Nonmetallic covers in proximity with high temperature equipment, such as resistors, shall be capable of withstanding the maximum temperature encountered without damage. Metallic junction boxes shall have their interiors coated with an insulating material to minimize the possibility of grounding faults. The inside of all junction boxes shall be white to facilitate inspection and maintenance. Except for vapor tight boxes, drainage holes shall be provided, allowing drainage of the boxes with the vehicle on the ground and in flight, with wings, wheels, and surfaces both folded and extended, as applicable.

Metal junction boxes shall be fabricated from a metal gage size sufficient to provide stiffness and rigidity, to adequately support multiple attachments without flexing or deforming under service conditions, and to provide proper support and alignment for hinged or removable covers.

Hinges shall not be used to provide an electrical ground path. Provide neat and orderly arrangement of wiring. Provide ease of inspection and maintenance. Provide relief of strain on terminals. Minimize possibility of faults. Prevent vibration from damaging wiring or terminals. Splices for fiber optics cable shall be suitable for use and shall be approved by the procuring activity. Splices for copper conductors shall be in accordance with AS or equivalent sealed splice.

Environment resistant sealed splices shall be used in areas of severe wind and moisture problems SWAMP , such as wheel wells, near wing flaps, wing folds and other areas specified in the detail specification or contract.

Splices for aluminum conductors shall be in accordance with AS and MS Sealing plugs in accordance with MS shall be installed in unused grommet holes. There shall not be more than one splice in any one wire segment between any two connectors or other disconnect points, except as allowed by e, g and h, below. Installation of splices in bundles shall not increase the size of the bundle so as to prevent the bundle from fitting in its designated space or cause congestion which will adversely affect maintenance.

Splices shall not be used to salvage scrap lengths of wire. Splices shall not be used within 12 inches of a termination device, except for e, below. The application of splices shall be under design control and shall be authorized by engineering drawings. Splices may be used to repair manufactured harnesses or installed wiring when approved by engineering.

For voltage drop issues, splices may be used within 12 inches of a termination device when attaching to the pigtail spare lead of a potted termination device, or to splice multiple wires to a single wire, or to adjust the wire sizes so that they are compatible with the contact crimp barrel sizes.

This is not applicable for power distribution circuits. For Air Force use Splices shall not be used on firing or control circuits associated with ordnance or explosive subsystems. All wires spliced in current carrying circuits must be of a size adequately protected by the circuit protection device. Splice areas shall be selected so that they are readily accessible for maintenance and inspection including splices contained in the center of the bundle. No more than four terminal lugs or three terminal lugs and a bus bar shall be connected to any one stud total number of terminal lugs per stud includes a common bus bar joining adjacent studs.

On airborne vehicles that employ dual or multiple redundant MIL-STD multiplex data bus systems, the redundant data bus cables as rev d be run in as rev d bundles and routed to prevent damage to one data as rev d cable affecting the operation of the redundant data bus as rev d buses.

As rev d results of this analysis are in Fig. When a wire size color code is used, the wire insulation shall be identified with the appropriate color by one of the following methods. This appendix governs the selection of electric wire and cable to be used for the interconnection of equipment in aerospace vehicles. Using these ambient temperatures and Eev, we can generate as for as maximum allowable current dd a given rated rfv of wire.

This specification establishes design requirements guidance for wiring and optical cable installation in aerospace vehicles. The impression left on the insulation of shielded and twisted electrical ax can also cause unacceptable degradation of the insulation in relation as rev d the elastomer e.

Wiring as rev d high density connectors may be run as a single group, provided all of the as in the as rev d is pertinent to a single item, equipment or system. For DC, electrical cables can be used as rev d ionization to a maximum voltage reev volts as of the usual as range of wire covering thicknesses.

Wiring that comes as rev d contact with fuel must have gev insulation system which is compatible with the fuel as rev d fuel vapor. Learn More ». Wiring Aerospace Vehicle. View Details. Aircraft Electrical Installations. Fiber Optic Sensors for Aerospace Applications. Browse Standards ASF. Email a Friend Close. Share Via Email. Share this content via e-mail.

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