MS3470A20-39S RECEP CONNECTOR BLACK

MS3470A20-39S — 39-Way Black MS3470 Threaded-Coupling Receptacle (Socket Contacts)

The MS3470A20-39S is a 39-way black anodised aluminium MS3470 circular mil-spec receptacle connector fitted with socket (female) contacts. Built to MIL-DTL-26482 Series II, this connector is designed for high-reliability motorsport wiring harness applications where a robust, sealed circular connector is required at a bulkhead, panel, or chassis junction point. The 39-way insert arrangement is among the highest-density configurations available in this shell size, making it suitable for the most complex motorsport harness junction points where circuit count is the primary design driver.

MS3474 / MS3470 Series — Mil-Spec Circular Connector Overview

The MS3474 and MS3470 connector families are manufactured to MIL-DTL-26482, the military standard for miniature circular electrical connectors. Both series use the same shell sizing and contact insert arrangements, making them inter-compatible in terms of contact accessories and wiring tooling. The key distinction is the coupling mechanism: MS3474 uses threaded-coupling coupling while MS3474 uses bayonet coupling. Both series accept size 16 and size 20 contacts (depending on insert arrangement) and are rated for use in environments subject to vibration, fluid exposure, and thermal cycling — exactly the conditions present in a motorsport vehicle.

Threaded-Coupling Coupling — MS3470

The threaded coupling mechanism provides a highly secure, vibration-resistant mated connection that is resistant to accidental unmating under shock and vibration loads. This makes the MS3470 series the preferred choice for connectors that remain permanently or semi-permanently mated in the vehicle — for example, engine block-mounted connectors, transmission tunnel bulkheads, and chassis-to-body harness interfaces.

Shell Size 20 — 39-Way Insert

Shell size 20 is used for very high circuit-count applications. The MS3470A20-39S is suited to main engine management harness bulkheads, data logger connectors, and primary PDM interfaces. The 39-way insert arrangement is among the highest-density configurations available in this shell size, making it suitable for the most complex motorsport harness junction points where circuit count is the primary design driver. The insert arrangement code -39S defines the exact contact pattern and gender; always cross-reference your harness schematic’s connector assignment against the full insert arrangement drawing to confirm pin-out before crimping the harness.

Black Anodised Aluminium Shell Finish

Black anodised shell connectors offer a visually distinctive finish that is popular in motorsport applications where aesthetics matter alongside engineering specification. The hard-anodised surface provides excellent abrasion resistance and corrosion protection comparable to the traditional olive-drab finish, making it equally suitable for harsh motorsport environments. The A-suffix finish designation is carried through all accessories in the MS connector ecosystem, ensuring a consistent finish across the complete connector assembly including backshell and accessories.

Socket (Female) Contacts

The socket (female) receptacle carries the contact arrangement with recessed socket contacts, providing mechanical protection for the contact faces when the connector is unmated. In motorsport practice, the socket receptacle is typically wired to the chassis or harness side of the connection where the connector may be exposed to contamination when the mating plug is disconnected. Contacts for this insert arrangement are size 16 or size 20 depending on the specific arrangement — consult the connector datasheet to confirm the correct contact part number and crimp tooling for your wire gauge.

Compatible Accessories

This receptacle is compatible with MS3420, MS3440, and equivalent Series II backshell accessories for strain relief and environmental sealing. Appropriate dust caps and protective covers are available for both mated and unmated connector storage and transport.

Available from Arctic Performance Parts

Arctic Performance Parts stocks a comprehensive range of MS3474 and MS3470 circular connectors in both olive-drab and black finishes, across all major shell sizes and insert arrangements. We supply professional harness builders, motorsport workshops, and performance enthusiasts across Scandinavia with genuine mil-spec connector components and the technical knowledge to specify them correctly. Lead time is 1–2 weeks for quantities beyond current stock levels.