Blue Sea Systems C-Series Flat Rocker Circuit Breaker, Triple Pole, 48V DC

Overview

The Blue Sea Systems C-Series Flat Rocker Circuit Breaker is a triple-pole magnetic hydraulic breaker for high-current DC circuits on boats, including inverter, bow thruster, and windlass installations. This range is available in 250A DC and 300A DC ratings, with a flat rocker actuator and trip-free operation so the breaker cannot be held closed after a trip.

It combines circuit switching and overcurrent protection in one panel-mounted unit, which helps keep heavy DC load controls simple at the helm, electrical panel, or equipment space. The breaker is rated up to 48V DC, has a 5000A interrupt capacity at 48V DC, and uses 1/4-20 tin-plated brass terminal studs for the main connections.

Key features

• Triple-pole C-Series breaker for high-current DC marine circuits.
• Magnetic hydraulic, trip-free breaker action cannot be forced closed during a fault condition.
• Flat rocker actuator sits flush in the ON position to reduce accidental switching around panels and equipment spaces.
• Color actuator indication makes the OFF position easy to identify during checks or troubleshooting.
• Paralleled poles use a 5/16 in. stud on the bus for heavy-current installations.
• Rated up to 48V DC with 5000A interrupt capacity at 48V DC.
• Operating temperature range from -40 C to 85 C supports use in demanding onboard locations.
• Rated for 10,000 switching cycles for repeated service as both breaker and switch.

Variants

This C-Series flat rocker breaker is offered in two DC amperage configurations for different high-current loads.

The amperage rating changes between variants. The triple-pole layout, flat rocker actuator, trip-free magnetic hydraulic breaker type, 48V DC maximum rating, 5000A interrupt capacity at 48V DC, and 1/4-20 tin-plated brass terminal studs remain consistent across these configurations.

• 7477, Amperage 250A DC. This rating suits high-current DC branches where the protected circuit and connected equipment call for a 250A breaker.
• 7554, Amperage 300A DC. This rating supports installations that require a 300A DC breaker for larger protected loads.

Installation and setup

This breaker is intended for panel mounting in a dry, accessible electrical location where the rocker can be seen and reached for service. The flat actuator is helpful on crowded panels because it does not protrude when the breaker is ON, reducing the chance of a sleeve, gear bag, or service tool switching it by accident.

Main terminals use 1/4-20 tin-plated brass studs with a terminal stud torque of 35 in-lb. Mounting uses 6-32 stainless steel screws with a mounting screw torque of 6 in-lb. Cable size, fuse coordination, and final breaker selection should match the equipment manual, conductor ampacity, voltage drop target, and the vessel's electrical standards.

Electrical and system integration

The breaker is a practical fit for DC power circuits feeding equipment with heavy startup and operating loads, such as inverters, bow thrusters, and windlasses. It gives the installer a single device that can isolate the circuit manually while also protecting the wiring from overcurrent conditions.

Because this is a high-amperage protection device, it should be installed close enough to the power source and equipment layout to keep cable runs clean while still remaining reachable for reset and inspection. It is not a substitute for proper cable sizing, secure terminations, and corrosion-aware wiring practices in the surrounding installation.