Keyed Battery Disconnect Switch

This keyed battery disconnect combines high-current DC power isolation with a removable-key lock mechanism, providing tamper-resistant control over vehicle and equipment battery power. Ideal for shared-fleet operations, construction sites, agricultural machinery, and any application where unauthorized power activation is a concern, the keyed mechanism requires the removable key to be inserted to rotate the disconnect out of the locked-OFF position. Once turned ON, the key can be removed and the disconnect remains conducting until the operator returns and turns it back to OFF.

Available in switch (503S) and disconnect (503D) configurations at 200 amp or 300 amp continuous ratings with working voltages up to 48 VDC, this keyed disconnect shares the same rugged mechanical design as its unkeyed counterparts. Sealed to IP67 and SAE J1455 for water, dust, and vibration resistance, the disconnect remains fully operational across a -40 to +85 degree Celsius operating range. The 503S switch uses silver-alloy contacts for 10,000 full make/break cycles under load, while the 503D disconnect uses copper contacts for 25,000 mechanical cycles suited to emergency isolation duty. Barrier-isolated terminals with 1,100-volt dielectric withstanding and greater than 100 megohms of insulation resistance ensure safe operation in exposed installations.

Voltage drop across contacts stays under 150 millivolts to minimize power loss in high-current cable runs. Panel-mounted through a 3/4-inch bushing with 18 ft-lb mounting torque and 13 ft-lb terminal torque, this keyed disconnect integrates cleanly into vehicle dashboards, engine compartments, battery boxes, and switchgear panels. Typical applications include commercial trucking fleets, agricultural equipment, construction machinery, boats, RVs, and any mobile installation where a keyed lockable battery disconnect is required for security or operator authorization.