ON-OFF Two-Position Rotary Battery Isolator Switch 300A Continuous Rating DC 12-24V Battery Disconnect Switch for Marine Boat RV

The MT014 is built for DC systems that pull real current. With a 300 amp continuous rating it sits comfortably above the average marine isolator, so it can serve as the main break on a boat where windlass, inverter, bow thruster and engine all share one feed — instead of being limited to a modest accessory circuit.
The working window is 12 to 24 volts DC. Two-position operation keeps the logic simple: turn the dial to ON and the battery is live; turn it to OFF and everything downstream is isolated. No auxiliary contacts, no combined-bank position, nothing that can be misread under pressure.
Copper components carry the current path, and the housing is moulded with a flat fixing flange, so the unit bolts to a console face, battery locker wall or steel bracket. The studs are large enough for heavy ring lugs — which matters once cable sizes grow to suit 300A.

• Headroom for startup surge — diesel cranking and inverter inrush sit more comfortably under a higher continuous figure.
• One switch for several loads — windlass, thruster and fuse board can share the same isolate point.
• Cooler joints — a heavier internal path spreads current, so stud temperature stays down during long charging runs.
• Fewer part numbers — the same switch covers 12V and 24V installations, cutting spares inventory.

• Two-position rotary dial with defined ON and OFF stops — no resting position between contacts.
• Copper conductors sized for the 300A continuous figure.
• Rigid moulded housing with a flat flange for panel fixing.
• Large terminal studs that accept standard crimped ring lugs.
• Face legend readable from a standing position and identifiable by touch.

Where the DC board carries a heavy consumer, this switch is usually placed right after the battery positive so the whole downstream run can be cut. Boats with a windlass or inverter, RVs running a large compressor fridge, and work vehicles feeding a winch or hydraulic pack are the usual candidates. It also suits yard equipment and trailers where a single master cut is required before maintenance.

1. Kill all loads, remove the battery negative lead, and confirm the cable is dead with a meter.
2. Position the switch so the dial swings freely and heavy cable can bend without kinking.
3. Mark the flange holes, drill, and fasten the body down evenly.
4. Land battery positive on one stud and the load or fuse block feed on the other.
5. Crimp ring lugs on both ends and torque the nuts fully — loose joints create heat at 300A.
6. Sweep the dial once without load, reconnect, then check stud temperature under working current.

Keep the switch at OFF during lay-up, transport and any repair work. Wash salt film off the housing after coastal trips, re-check nut torque each season, and replace any cable with corroded lugs rather than retightening it. Remember that the isolator is only one part of the circuit — cable gauge must match the 300A rating, and every joint must be sound.

• Minimum order — 5 pcs.
• Price — negotiable, quoted against quantity and packing requirements.
• Capacity — 50,000 pcs per month.
• Lead time — 30 days for standard production.
• Payment — T/T or Western Union; 30% deposit with the balance before shipment.
• Packing — neutral white box inside a brown carton; branded packing available with written trademark authorisation.