MIL-DTL-24640/25 9XS Shipboard Cable

Mil-Spec Military part number MIL-DTL-24640/25 has two cable-type designations: 9XS. The cable is rated for 600 volts and uses twisted pair identification codes by applying Method 2.  24640/25 cords use Extruded irradiated cross-linked Polyalkene insulation with irradiated cross-linked Polyvinylidene Fluoride (PVDF) insulation and have a low-smoke zero-halogen (LSZH) cross-linked polyolefin (XLPO) jacket. Component wires will be SAE-AS81044 except that print identification will be per MIL-SPEC-24640. The cable has four pairs of conductors, with twisted pairs of two component wires, one black and one white twisted together to form a pair. One additional conductor, also in compliance with SAE-AS81044 as stipulated above will be added. All conductors are insulated as discussed above and tested in accordance with SAE-AS81044/12 except that the identification will be according to MIL-STD-24640. The required number of shielded pairs is then combined into a single assembly, which is then enclosed in a 34 AWG tin-coated copper braid shield. Fillers may be used to create a firm, well-rounded cable which is finally placed into a cross-linked polyolefin (XLPO) jacket. These cords are lightweight, non-watertight, and have non-flexing service. These cables operate within a temperature range of -20°C to +105°C. Non-watertight cables can be used within one or two continuous compartments, but are not permitted to penetrate bulkheads or watertight decks.

What does the cable designation 9XS mean?

In the cable designation for 9XS, 9 refers to nine conductors, X refers to irradiated cross-linked Polyalkene insulation with irradiated cross-linked Polyvinylidene Fluoride (PVDF) insulation, and S refers to individual tin-coated copper braided shields for each set of conductors.

M24640/25 Construction:

• Conductors: Stranded tin-coated copper conductors
• Insulation: Extruded irradiated cross-linked Polyalkene insulation with irradiated cross-linked Polyvinylidene Fluoride (PVDF) insulation
• Shielding: The cable features an overall optimized tin-coated copper braided shield
• Jacket: Low-smoke zero-halogen (LSZH) cross-linked polyolefin (XLPO).

M24640/25 Ratings and Approvals

• Mil-Spec: MIL-DTL-24640
• Navy Shipboard Spec: 9XS
• SAE-AS81044/12 except that the identification will be according to MIL-STD-24640
• Voltage Rating: 600V

Features and Benefits of M24640/25 Cords

• Cross-linked polyalkene/polyvinylidene fluoride insulation provides protection in environments with ultra-high vacuum, high temperatures, and ionizing radiation.
• LSZH jacket is fire resistant and emits low smoke, which is ideal for shipboard settings which often have restricted ventilation
• LSZH jackets also emit low acid, gas, and toxicity when subjected to fire, maintaining circuit integrity
• Individually shielded conductors reduce electrical noise created by electromagnetic signals in the cable while also providing greater protection and durability than unshielded cables.
• Braided shielding is heavier than foil shielding and provides additional protection against EMI/RFI as well as protecting the cable in rugged environments. The braided shield also provides better grounding than foil shields.