CPC Backshell with Cable Clamp, Shell Size 17
The TE Connectivity 213904-3 is a backshell with integrated cable clamp for the CPC (Circular Plastic Connector) series 5, shell size 17. It provides strain relief and cable management for the round cable bundle exiting the connector at 180°. The 0.453" (11.51mm) cable opening sets the maximum bundle diameter that can pass through the clamp — a critical dimension when routing a multi-conductor cable into the back of a mated CPC pair. The clamp screws are included in the package (5 pieces total: 3 cable clamp parts, 2 screws), so no separate hardware sourcing is needed for the cable clamp assembly.
Thread Fit and Shell Compatibility
The 15/16-20 UNEF thread mates directly with the CPC connector shell size 17. This is the mechanical interface — if the connector shell does not carry this thread, the backshell will not engage. The thread is a UNEF (Unified Extra Fine) series, which means the pitch is finer than standard UNC/UNF, providing more thread engagement in the thin-wall plastic shell of the CPC connector. The backshell is explicitly listed for use with CPC Connector, Series 5, so it is a direct fit for that connector family without adapters.
Material and Environmental Rating
The housing is molded from polyamide (nylon), a standard choice for circular connector backshells that balances mechanical strength with light weight. The black color is typical for industrial-grade CPC accessories. No IP rating is listed for this backshell alone — the seal integrity of the mated assembly depends on the connector pair's own sealing, not this accessory.