crimping, interconnecting cables, harnesses, and wiring - NASA

Figure 19-14. Western Union/Lineman Splice
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NASA-STD-8739.4 with Change 6
19.9.1 Preparation. The conductors shall be pre-tinned (Requirement). There shall be at least 3
turns around each conductor and the wraps shall be tight with no gaps between adjacent turns
(see Figure 19-15) (Requirement). The wraps shall not overlap and the ends of the wrap shall be
trimmed flush prior to soldering to prevent protruding ends (Requirement). Conductors shall not
overlap the insulation of the other wire (see Figure 19-16) (Requirement).
Figure 19-15. Initial Wrap for
Western Union/Lineman Splice
Figure 19-16. Completed Wrap for
Western Union/Lineman Splice
19.9.2 Soldering. The termination shall comply with all the requirements of NASA-STD-
8739.3 for a solder termination (Requirement). Solder shall wet all elements of the connection
(Requirement). The solder shall fillet between connection elements over the complete periphery
of the connection (see Figure 19-17) (Requirement).
19.10 Solder Ferrule
Figure 19-17. Soldered Western Union/Lineman Splice
The solder ferrule splice (see Figure 19-19) is fabricated using a crimp ferrule. This splice may
only be fabricated as an end splice. Select the ferrule so that the ferrule fits over the inserted
tinned wires, but not over the wire insulation. Maximum insulation clearance: the diameter of
the ferrule. Minimum insulation clearance: the insulation does not interfere with the natural
formation of the solder fillet. Maximum protrusion from the end of the ferrule: one wire
diameter of the largest wire in the wire bundle. The minimum protrusion from the end of the
ferrule: even with the end of the ferrule and visible after soldering. The solder shall fill the
ferrule and be visible at both ends (Requirement).