700A Cranking 525A Intermittent Marine Battery Isolator Switch with ON-OFF Two-Position Rotary Boat Battery Disconnect Switch

Buyers tend to over-buy on amps and under-think on terminals. The MT080 sits in the useful middle: 350A continuous at DC 32V, with a five-minute window at 525A and a 700A cranking burst — enough for a 24V boat or work truck, without paying for a frame the installation will never use.

The dial is a plain ON-OFF rotary with a positive stop, so the state of the circuit can be read by hand in a dark locker. The rest of this page is about sizing the switch honestly and making the joints that carry the current behave.

1. Count the continuous load first. Everything that can run at once — lights, pumps, fridge, electronics — adds up to the figure you must stay under for hours. That is the 350A line.
2. Add the heavy manoeuvring loads. Thrusters, winches and windlasses push past continuous for a few minutes at a time. The 525A rating covers those bursts; it is not a place to park a load.
3. Reserve 700A for the key. Only a cranking motor pulls that much, and only for seconds. Size nothing against it except the fuse curve and your peace of mind.
4. Step up when the sums exceed the line. If the continuous total approaches 350A, move to a larger frame rather than leaning on the intermittent figure. A switch running at its ceiling ages faster than the boat around it.

• Lug contact area. Use closed ring lugs that sit flat on the stud face. A lug riding on a washer or a burr creates a hot spot that no rating on the label can fix.
• Torque, then re-torque. Tighten both studs fully at installation and again after the first week of service. Thermal cycling settles a joint that looked tight on day one.
• Temperature is the honest gauge. After a loaded run, put a hand on each stud. Slightly warm is normal; too hot to hold means the joint, not the switch, is the problem.
• Keep the cable short and supported. Long unsupported runs vibrate at the stud. Clamp the cable within a short distance of the terminal so the switch carries no mechanical load.

• Flat, rigid panel. The rear base needs solid material. A flexing surface lets the stud nuts back off over a season.
• Dial visible from the helm or hatch. The point of a mechanical isolator is that the position can be checked at a glance, so mount where it can be seen and reached.
• Clear of spray and standing water. The body joint is sealed, but a switch sitting in a puddle is still a bad installation.
• Ahead of the fuse panel. Break the positive feed before it reaches distribution, so everything downstream goes dead with one turn.

MT080, ON-OFF rotary isolator, DC 32V maximum, 350A continuous, 525A intermittent and 700A cranking. There is no minimum order quantity — single units, samples and mixed containers are all accepted, with pricing quoted against quantity and packing. Standard production runs 30 days from deposit; T/T or Western Union, 30% down with the balance before shipment. Units ship in cartons, and pallet quantities can be quoted separately.

• Marine Battery Isolator Switch
• Marine Isolating Switch
• Boat Isolator Switch