What This Connector Is and Where It Fits
The JST B03B-WPJRS-2(LF)(SN) is a 3-position single-row header from the WPJ series, designed for board-to-cable/wire interconnects that need a sealed, vibration-resistant connection. It carries a 5.00 mm pitch, rated 7 A per circuit at 300 V, with tin-plated contacts on both the mating and solder sides. The housing is a red, glass-filled PBT rated UL94 V-0, and the connector is fully shrouded on all four walls with a latch holder for positive retention. The waterproof ingress protection makes this header suited for outdoor, washdown, or high-humidity environments where moisture would corrode an unsealed connector. The operating temperature range of -25°C to 85°C covers automotive cabin, industrial cabinet, and telecom enclosure conditions.
Key Ratings and What They Mean for Your Build
The 5.00 mm pitch gives enough room for the 300 V rating without forcing an oversized board footprint — it's a common spacing for power and signal in sealed harnesses. The 7 A per-contact rating is derated from the 85°C upper limit; if your enclosure runs hot, expect to drop current. The tin-plated contacts are rated for a moderate number of mating cycles — fine for field-service connections, but not for frequent reconnects in a test fixture. The latch holder locks the mated pair against vibration, so it won't shake loose on a moving assembly. The mated stacking height of 25.3 mm is set by the mating receptacle housing — the board-mount header's insulation height is 21.41 mm above the PCB surface, with a solder post length of 3.30 mm. The board guide feature helps align the connector during assembly, reducing the risk of bent pins.
Mating and Termination
This header mates with the JST WPJ series receptacle housing (crimp terminal style) — the latch holder on the header engages the matching lock on the receptacle. The through-hole solder termination is straightforward for wave or hand soldering. The square male pins accept the receptacle's female crimp terminals, which are ordered separately.