Pollak 21-657 Precision Ball Switch – Normally Closed (NC), Screw Terminals

Reliable "Break-on-Contact" Precision for Heavy-Duty Systems

The Pollak 21-657 Precision Ball Switch is a professional-grade electrical component engineered for the demanding environments of the trucking, agricultural, and industrial sectors. This Normally Closed (NC) switch is designed to keep a circuit active until the ball plunger is depressed, making it the ideal choice for safety interlocks, neutral sensing, and specialized lighting systems that require a "cut-off" signal upon engagement.

Secure and Versatile Screw Terminal Design Equipped with robust screw terminals, the 21-657 offers maximum installation flexibility. This design allows for a direct, high-conductivity connection using standard ring or spade terminals, making it an excellent choice for custom wiring harnesses or quick field repairs where specialized mating connectors are not available.

Built for the Long Haul Pollak switches are the industry standard for durability. The 21-657 is constructed with a corrosion-resistant body and is designed to thrive in extreme temperatures ranging from -40°F to +250°F. With a mechanical life of 1,000,000 cycles, this switch provides the long-term reliability needed to minimize vehicle downtime and ensure consistent performance in high-vibration areas like transmissions and chassis mounts.

Key Specifications:

• Circuitry: Normally Closed (NC)

• Termination: Two (2) Screw Terminals

• Thread Size: 9/16-18

• Hex Size: 7/8"

• Voltage Rating: 5.0 - 24.0 VDC

• Current Rating: 0.01 - 5.0 DC Amp

• Operating Temperature: -40°F to +250°F (-40°C to +121°C)

• Cycle Life: 500,000 Electrical / 1,000,000 Mechanical

• Sealing: Includes O-ring seal for a leak-proof fitment.