Ashcroft B420B Snap Action Switch

The Ashcroft B420B Snap Action Switch is a mechanical pressure switch in the Ashcroft B-Series lineup that integrates a pressure-sensing element with a snap-action electrical contact to deliver a fast, definitive output as system pressure crosses a preset point. It is designed for reliable use in industrial and OEM hydraulic and pneumatic control circuits where an electrical signal is required to trigger alarms, interlocks, or safety cutoffs. Configurations in the B420B family include options such as the B420B30PSI (30 psi) with a Buna-N diaphragm and a 1/4 in. NPT female mounting port, and the B420B100 variant offering a 100 psi set point, giving users practical choices across low- to mid-range pressures. The series carries a 15 A electrical rating at 125/250 VAC, enabling direct connection to standard control relays and controllers without an intermediate interface. Designed for rugged service, the B420B combines Ashcroft’s legacy of durable pressure sensing with a compact form factor and straightforward electrical integration, making it well suited for pressure-monitoring duties, alarms, and control logic in demanding hydraulic and pneumatic systems.