crimping, interconnecting cables, harnesses, and wiring - NASA
crimping, interconnecting cables, harnesses, and wiring - NASA
crimping, interconnecting cables, harnesses, and wiring - NASA
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Page 82 of 114<br />
<strong>NASA</strong>-STD-8739.4 with Change 6<br />
Figure 19-1. Pre-Tinned Conductors Figure 19-2. Soldered Conductors<br />
19.6.1 Preparation. The conductors shall be pre-tinned, parallel to, <strong>and</strong> in contact with each<br />
other at least three (3) wire diameters, but not more than six (6) wire diameters (Requirement).<br />
The conductors to be spliced shall not be twisted together (Requirement). Conductors shall not<br />
overlap the insulation of the other wire (Requirement). There shall be no protruding wire str<strong>and</strong>s<br />
(Requirement).<br />
19.6.2 Soldering. Apply solder so that a fillet forms on both sides of the conductors for the<br />
entire length of the area where they overlap. After soldering, the conductors’ contours shall be<br />
discernible (see Figures 19-3 <strong>and</strong> 19-4) (Requirement).<br />
Figure 19-3. Sleeving over Soldered<br />
Connection<br />
19.7 Lash Splice<br />
Figure 19-4. Double Sleeving over Soldered<br />
Connection<br />
A lash splice (see Figure 19-6) is a soldered splice identical to the lap splice (see Figure 19-2)<br />
except for the addition of a single str<strong>and</strong> wire winding (overlash) that binds the conductors<br />
together.<br />
19.7.1 Preparation. The conductors to be spliced shall be pre-tinned (see Figure 19-5), parallel<br />
to, <strong>and</strong> in contact with each other at least three (3) wire diameters, but not more than six (6) wire<br />
diameters. The conductors to be spliced shall not be twisted together (Requirement).<br />
Conductors shall not overlap the insulation of the other wire (Requirement). There shall be no<br />
protruding wire str<strong>and</strong>s (Requirement).<br />
Figure 19-5. Pre-Tinned<br />
Conductors<br />
Figure 19-6. Lashing of<br />
Pre-Tinned Conductors<br />
Figure 19-7. Soldered<br />
Connection<br />
The wire used to lash the conductors together shall be a solid wire (Requirement). It shall be<br />
wrapped a minimum of 6 turns <strong>and</strong> the wraps shall not extend past the end of either conductor<br />
(see Figure 19-6) (Requirement). The lash may be either open spiral (no more than 2 lashing<br />
wire diameters between turns) or closed (each wrap is in contact with its adjacent wrap). The<br />
wraps shall not overlap <strong>and</strong> the ends of the wrap shall be trimmed flush prior to soldering to<br />
prevent the ends from protruding through insulation (Requirement). An alternative configuration<br />
for the lash splice is the Lash End Type Splice (see Figures 19-8 <strong>and</strong> 19-9).
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