Blue Sea Systems COTS Military Grade A-Series Magnetic Hydraulic Circuit Breaker, 2 Pole, 277V AC, 65V DC, Metal Toggle, Trip-Free

Overview

The Blue Sea Systems COTS Military Grade A-Series is a double-pole magnetic hydraulic circuit breaker range for marine electrical panels and other demanding onboard AC or DC circuits. These breakers combine switching and circuit protection in one panel-mounted unit, with amperage options from 5A to 50A for matching the breaker to the protected wiring and load.

The series uses a metal toggle actuator, a trip-free breaker mechanism, and two poles for circuits that need both conductors opened together. Shared ratings across the range include 277V AC, 65V DC, 1500A AC interrupt capacity, 7500A DC interrupt capacity, and an operating temperature range from -40°C to 85°C.

For marine installations, the stainless steel mounting boss and #10-32 stainless steel terminal screws help support secure panel mounting and electrical connections in areas exposed to vibration and routine service access. This is a practical fit for builders, refit shops, and vessel owners working with Blue Sea Systems A-Series panel layouts or COTS military grade circuit protection requirements.

Key features

• Double-pole A-Series breaker with a metal toggle actuator for panel-mounted switching and circuit protection.
• Magnetic hydraulic, trip-free mechanism cannot be held ON during a fault current condition.
• Rated for use up to 277V AC and 65V DC, allowing one breaker family to cover many onboard AC and DC protection layouts.
• Interrupt capacity of 1500A AC and 7500A DC for fault current protection within the breaker rating.
• Operating temperature range from -40°C to 85°C for engine rooms, technical spaces, and other locations where temperature swings matter.
• 1/2-32 hex nut stainless steel mounting boss with 30 in-lb mounting nut torque for secure panel installation.
• #10-32 stainless steel terminal screws with 14 in-lb screw terminal torque for controlled electrical terminations.
• Rated for 6000 electrical switching cycles and 4000 mechanical cycles.
• UL 1077 recognized for supplementary circuit protection applications.

Variants

This product family is offered in eight amperage ratings: 5A, 10A, 15A, 20A, 25A, 30A, 40A, and 50A. The amperage rating is the selection that changes across the range, so the correct choice should match the conductor size, protected load, and the vessel electrical plan.

The shared A-Series construction, double-pole layout, metal toggle actuator, voltage ratings, interrupt capacities, terminal hardware, and operating temperature range remain consistent across these amperage options.

Installation and setup

Mount the breaker in a compatible panel cutout using the 1/2-32 stainless steel mounting boss, then tighten the mounting nut to 30 in-lb. Electrical connections use #10-32 stainless steel terminal screws, with a specified screw terminal torque of 14 in-lb. Using the stated torque values helps avoid loose connections without overstressing the hardware.

Because this is a protective device, the amperage selection should be based on the wire and circuit it protects, not just the connected equipment draw. It belongs in installations where the breaker rating, wire gauge, voltage, and available fault current have all been checked against the vessel electrical design.

Electrical protection and system use

The double-pole format is commonly used where both sides of a circuit need to be disconnected together, including many AC main protection layouts. The trip-free action is important on board because the breaker can still open under fault conditions even if the toggle is held in the ON position.

These breakers suit marine electrical panels on workboats, patrol boats, refit projects, and other vessels where a compact panel breaker must handle frequent operation, vibration, and wide temperature exposure while keeping the circuit layout serviceable.