crimping, interconnecting cables, harnesses, and wiring - NASA

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NASA-STD-8739.4 with Change 6
When crimping multiple wires into a contact, the total circular-mil-area (CMA) of all the wires
must be calculated into an Equivalent Wire Size (EWS) in order to select the properly sized
contact. Find the wire size that matches the calculated EWS and select the contact based on that
wire size. If the calculated EWS does not exactly match a single wire size, use the wire size that
is next largest to the calculated CMA to select the contact size.
19.12 Modified Crimp Contact
Figure 19-20. Stripped Wires Prior to Insertion
Use the appropriate crimping tool and positioner. Determine the crimp tool selector setting
based on the contact and “equivalent” wire size. Strip the wires to be spliced. The wires being
spliced shall not be twisted and shall be inserted into the barrel parallel to each other (see Figures
19-20 and 19-21) (Requirement). All wires shall be seated against the bottom of the barrel (see
Figure 19-22 (Requirement)). Crimp and inspect per the requirements of this document. The pin
section of the contact shall be trimmed at its base and deburred (see Figure 19-23)
(Requirement). Cuts extending into the crimp barrel body or distortions of the crimp barrel body
shall be cause for rejection (Requirement). Shrink sleeving shall be installed over the
termination so that it extends at least 2 crimp barrel diameters beyond the end of the contact and
beyond the insulation of the wire that has the greatest insulation gap (see Figure 19-24)
(Requirement).
Figure 19-21. Stripped Wire
Bundle Prior to Insertion
Figure 19-23. Contact Trimmed
and Deburred
19.13 Crimp Ferrule Splice
Figure 19-22. Wires Crimped
Within Contact
Figure 19-24. Contact Covered With
Shrink Sleeving
The Crimp Ferrule method is used for splicing wires together without soldering. The tooling
verification process shall comply with all the requirements of this document for a crimp