Loaded positions and body size
The 77316-852LF is a 9-position BergStik header body, but only 3 positions are loaded with pins. This is a breakaway design — the unloaded positions are empty plastic, so the board footprint must match the full 9-position pattern even though only three circuits carry signal.
Current and temperature envelope
The 3 A figure is a per-contact limit — if all three loaded pins carry current simultaneously, the total is 9 A, but the housing's UL94 V-0 thermoplastic material and the 0.094" (2.40 mm) insulation height set the real thermal ceiling.