Board-fit and wire-mating basics
The 644753-2 is a vertical through-hole header from the MTA-156 series, with 2 positions on a 0.156" (3.96mm) pitch. The single-row layout mates with MTA-156 crimp-socket receptacles for board-to-cable/wire connections. The friction lock provides a positive detent when mated — it resists vibration loosening without needing a secondary latch or screw.
Current rating and wire gauge reality
For 18 AWG wire, expect around 7 A per circuit at a 30°C temperature rise; for 22 AWG, derate to about 5 A. The 600VAC rating is a dielectric withstand limit, not a continuous operating voltage — stay within the system's working voltage.