The MMTC 32NO-WB NEMA 4 Pneumatic Exterior 2 Wire Air Switch is a weather-sealed, air-actuated switch designed for outdoor alert and control applications. When air pressure is applied via a connected hose or tubing, it provides a momentary, normally open contact closure on a simple two-conductor circuit. Commonly used to trigger driveway bells, alarms, counters, relays, and similar controls, it’s a reliable choice for drive-thru lanes, car washes, service stations, loading docks, warehouses, and gate or door alert systems. As a two-wire, normally open device, it serves as a straightforward replacement part or upgrade for many existing pneumatic driveway signal and alarm setups that require a dry-contact input.
Housed in a NEMA 4 enclosure for exterior durability and washdown resistance, the 32NO-WB isolates electrical contacts from the traffic area and moisture by using pneumatic activation—no power is required at the switch, and it interfaces with compatible low-voltage or control circuits per the connected device’s ratings. Installation typically involves mounting the enclosure in a convenient location, landing the two wires on the receiving device’s N.O. input terminals, and attaching the air line or driveway hose to the switch’s fitting, then routing the hose where vehicles will pass. For safe operation, follow applicable codes, disconnect power before wiring, and verify that the connected bell, relay, counter, or controller accepts a normally open dry-contact trigger. This MMTC air switch supports residential and commercial applications where a universal, exterior, 2-wire pneumatic trigger is needed.