A terminal block manufacturer and customer have cooperated and have developed a successful series of surface mount connectors that have evolved from an equally successful series of through-hole connectors. Printed circuit board components using surface mount technology had the reputation of not having the inherent reliability of those using through-hole solder joints. This has been problematic for connectors having 10-ampere current ratings. The wire sizes used can exert forces that stress the solder joints. These forces can be technicians tugging during wire pulling, residual stress in stiff wires, the enclosure's pressure on stiff wires, the inertia of the wire during impacts, resonance and vibrations transmitted through the wire and excessive torque applied to screws. One solution is to attach the wires to a plug connector that is self-staked to a base plate (or free to move) and then mates with a PCB surface mounted pin strip header. A combination of good solder joint strength, reduced application stresses and the mitigation of human factors have resulted in strong and reliable connections. This paper shows that the solder joints have the strength and the shape required to make a consistently safe and reliable field proven connection that meets application and regulatory requirements.
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