Pollak 21-435 Precision Ball Switch – Normally Closed (N.C.) with Screw Terminals

Precision Sensing for Safety and Control Circuits

The Pollak 21-435 Precision Ball Switch is a heavy-duty, Single Pole Single Throw (SPST) switch designed for specialized automotive and industrial applications. Unlike standard "normally open" switches, the 21-435 is a Normally Closed (N.C.) component. This means the electrical circuit remains closed (On) until the ball is depressed, at which point the circuit is interrupted (Off).

Secure Screw Terminal Connection Engineered for maximum reliability and ease of field service, the 21-435 features threaded screw terminals. This design allows for a secure, bolted connection using ring or spade terminals, ensuring your wiring stays intact even under the heavy vibration and mechanical stress common in trucking and construction environments.

Heavy-Duty OEM Quality Built to survive the toughest conditions, this switch is housed in a rugged, zinc-plated metal body that resists corrosion, grease, and road salt. The precision-ground ball provides smooth, consistent actuation, making it an ideal choice for door-ajar sensors, compartment lighting, or safety interlock systems where a "signal-on-release" is required.

Key Features:

• Normally Closed (N.C.) Function: Circuit is "On" until the ball is depressed.

• Screw Terminal Interface: Provides a high-vibration resistant connection for ring terminals.

• Corrosion-Resistant Housing: Zinc-plated metal construction for long-term durability.

• Precision Actuation: Engineered with tight tolerances for accurate and repeatable switching.

• Universal 12V/24V Support: Compatible with standard commercial and industrial electrical systems.

Common Applications:

• Door-Ajar and Cabinet Lighting (Lights on when door opens)

• Safety Interlock and Limit Switching

• Emergency Brake Warning Indicators

• Specialized Gearbox and PTO Sensing

• Industrial Machine Guard Monitoring