Heat shrink tubing is opaque, prohibiting visual inspection of the termination. The heat shrink tubing conforms to the crimp outline and extends over the wire the proper length, but does not follow the contour of the wire, or provide any sealing or strain relief. Heat shrink tubing conforms to the crimp outline, but does not extend over the wire to provide any sealing or strain relief to the conductor.Īn incomplete or improper conductor crimp will produce a conductor-crimp termination with reduced mechanical strength and reduced reliability.Īn incomplete or improperly set insulation crimp will produce a termination with reduced mechanical strength and reduced reliability. The indents shall not encroach on or distort the inspection hole. The conductor should extend a minimum of flush with, and a maximum of one (1) wire diameter beyond the conductor crimp edge.Įxposed base metal reduces the reliability of the crimp. Slight scuffing or discoloration is acceptable.Ī damaged or deformed crimp indicates the use of an incorrect crimp positioner and/or improper insertion into the crimp tool.ĭisturbing the lay of wire strands during crimping may reduce the reliability of the crimp termination.Įxcessive edge flash or insulation whiskers that extend into the conductor crimp section may interfere with the proper mechanical and electrical termination of the crimp. NASA-STD-8739.4, , Ĭut, crushed, gouged, damaged or nicked insulation may result in reduced electrical isolation and/or short circuits. Modifying the crimp, to accommodate an undersized/oversized conductor (A) or termination (B), reduces the mechanical strength and reliability of the conductor-crimp termination. Tarnish, corrosion and/or contamination reduces the reliablity of the crimp contact.Ĭracks in the crimp barrel reduce the mechanical reliability of the conductor-crimp termination. The heat shrink tubing has been exposed to excessive heat, resulting in charring and splitting of the sleeve and possible damage to the conductor. Evidence of burning or charring is not acceptable.īirdcaged strands reduce the conductor's overall strength and increase the possibility of shorting. Slight discoloration of the shrink tubing is acceptable. Overlaps meet minimum electrical spacing and provide strain relief. Tubing is tight, symmetrical, undamaged (slight discoloration is acceptable). Preferably, the wire end should be bottomed in the crimp barrel.Īt a minimum, the ends of the wire strands shall be visible in the inspection hole, indicating that the conductor has been properly inserted in the crimp barrel. The wire strands shall be visible in the inspection hole, indicating that the conductor is properly inserted. The conductor should extend a minimum of even with, and a maximum of one wire diameter beyond, the conductor crimp edge. The minimum insulation clearance for all crimped connections is 0.25 mm (0.010 in.).Ĭrimping of solid wire, component leads, or stranded wire that has been solder-tinned, is prohibited. For 18 AWG and larger conductors, the maximum clearance is 1.25 mm (0.05 in.). For conductors 20 AWG and smaller, the maximum clearance is 0.75 mm (0.030 in.).Ģ. Crimp indents shall not encroach on the wire entry shoulder or the inspection hole/wire exit shoulder.ġ. See 2.02 - 2.10 for specific accept/reject criteria applicable to individual crimp styles.Ĭrimp indents should be centered between the wire entry shoulder of the crimp barrel and the inspection hole/wire exit shoulder. This section details the generic accept/reject criteria of commonly used crimp termination styles. CRIMPED TERMINATIONS GENERAL REQUIREMENTS CRIMPED TERMINATIONSĬrimping is an efficient and highly reliable method to assemble and terminate conductors, and typically provides a stronger, more reliable termination method than that achieved by soldering.Ĭrimp terminations are available in different styles, depending upon the design application and connectivity requirements.
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