Blue Sea 300A Red Mini m-Series On/Off Battery Switch w/ Lockable Key

Secure High-Current Switching for Marine and Vehicle Systems

The Blue Sea m-Series Battery Switch sets the standard for compact, high-performance power isolation. Designed for marine, caravan, and RV applications, this switch manages a single battery bank, allowing users to safely disconnect power during maintenance or storage. With a continuous rating of 300 Amps, it is perfectly sized for outboards, small petrol engines, and diesel engines, providing robust power handling without the bulk of industrial-grade switches.

Integrating a battery switch is essential for preserving battery life. By turning the switch to the 'Off' position, you eliminate parasitic loads that slowly drain batteries over time. This ensures that when you return to your boat or vehicle, your power system is ready to go. Its compact form factor allows for installation in tight spaces where traditional heavy-duty switches cannot fit.

Lockable Security for Safety and Theft Prevention

A standout feature of this specific model is the lockable key mechanism. Unlike standard rotary switches, this unit includes a removable key that secures the switch in the 'Off' position. This functionality provides two critical benefits: enhanced security and maintenance safety.

For vessel or vehicle owners, the key acts as a theft deterrent, preventing unauthorised use of the engine or electrical system. For technicians and DIY enthusiasts, it serves as a safety lockout, ensuring the circuit cannot be accidentally energised while working on the electrical system. This reduces the risk of short circuits and electrical shock during repairs.

Engineered for Harsh Environments

Reliability in marine environments requires superior materials. The m-Series uses tin-plated copper studs to offer maximum conductivity while resisting corrosion caused by salt mist and humidity. The studs feature a one-piece design, which is a significant improvement over standard two-piece bolts. This design ensures the stud never loosens from the switch body over time, maintaining a solid electrical connection and reducing the risk of overheating—a common point of failure in generic switches.

The unit is housed in a reinforced casing with an isolating cover that protects the rear contacts from accidental shorting. Breakout tabs on the cover allow for wire access in any direction, simplifying the wiring process in complex setups.

Versatile Connection Options

The switch is designed to accommodate modern heavy-duty cabling. The 3/8" (Approx. M10) stud terminals are robust enough to accept heavy-duty lugs, ensuring secure, low-resistance connections. With a stud length of 7/8" (22 mm), the terminals can accept multiple cable lugs, allowing for easy integration of additional loads or charging sources directly at the switch.

• 300 Amps continuous rating handles substantial 12V, 24V, and 48V loads comfortably.
• Lockable key design prevents accidental activation and enhances security.
• Tin-plated copper studs ensure maximum corrosion resistance and electrical flow.
• One-piece terminal studs prevent loosening, reducing fire risks and connection failures.
• Flexible mounting with breakout tabs supports various cable entry angles.
• Ignition protected marking makes it safe for installation aboard petrol-powered boats.

Improve System Safety Today

Upgrade your battery management system with the Blue Sea m-Series Lockable Switch. Whether you need to secure a vehicle against theft or ensure safe isolation for maintenance, this switch delivers professional-grade performance in a compact package.