Blue Sea Systems m-Series Mini Single Circuit ON-OFF Battery Switch with Knob, 48V DC, 300A

Overview

The Blue Sea Systems m-Series Mini On-Off Battery Switch with Knob is a compact single-circuit battery switch for controlling one battery or battery bank feeding one load group. It has two positions, ON and OFF, with a maximum voltage rating of 48V DC, a 300A continuous rating, a 500A intermittent rating for 5 minutes, and a 900A starting rating for 30 seconds.

This switch suits small boat battery isolation, outboard installations, and gasoline or diesel engine circuits where a simple manual disconnect is needed near the battery, helm, or electrical panel. The IP66 rating helps it handle spray and washdown exposure, while ignition protection supports installation aboard gasoline-powered boats when fitted correctly.

The m-Series case supports surface, front panel, or rear panel mounting, which gives installers more flexibility in tight lockers and console spaces. Rear contacts are protected by an isolating cover with snap-on sections, and the 3/8"-16 M10 tinned copper terminal studs are sized for heavy battery cables up to the listed 4/0 AWG rating requirement.

Key features

• Single Circuit ON-OFF switching for one battery or battery bank feeding one load group.
• Rated for 48V DC maximum, 300A continuous, 500A intermittent for 5 minutes, and 900A starting for 30 seconds.
• IP66 rating for protection against powerful water jets in exposed marine areas.
• Ignition protected for use aboard gasoline-powered boats when installed according to the vessel electrical plan.
• Mounts on the surface, through the front of a panel, or from the rear of a panel.
• 3/8"-16 M10 tinned copper terminal studs support secure battery cable connections and resist corrosion at the contact points.
• Accepts #10 mounting screws and provides 1.12 in of cable clearance for 4/0 AWG cable routing.
• No battery combine function and no alternator field disconnect, keeping the operation simple for a basic ON-OFF battery isolation circuit.

Variants

This battery switch is offered in two color configurations. The functional switch type remains the same across both versions, with the color changing to match the boat’s panel layout, labeling style, or owner preference.

Both variants use the same m-Series Mini single-circuit ON-OFF format, the same knob-style operation, and the same main electrical ratings.

• 6006: Red knob. The red knob gives the battery isolation point a high-visibility look, which can be helpful in battery lockers, consoles, and service areas.
• 6006200: Black knob. The black knob gives the switch a lower-profile appearance for helm panels, dark consoles, and installations where the switch should blend in visually.

Installation and fit

Before installation, confirm the circuit layout, cable size, overcurrent protection, and mounting location against the boat’s electrical system. This is a manual battery switch, so it should be placed where it can be reached for routine shutdown, service work, and emergency isolation without interfering with cable bends or terminal covers.

The 120 in-lb terminal stud torque rating matters during installation because loose battery terminals can create heat and voltage drop under starting loads. Leave enough room behind the panel for the isolating cover, cable entry direction, and the bend radius of heavy battery cable.

Use cases on board

This switch is a good match for boat owners who need a straightforward battery disconnect for a single battery bank, especially on small powerboats, center consoles, fishing boats, tenders, and compact engine installations. It also works well where the electrical system does not need battery combining or a selector function.

For multi-bank systems, emergency paralleling, or alternator field disconnect requirements, confirm that this single-circuit ON-OFF layout matches the full battery management plan before ordering.