Blue Sea 7271 300A C-Series Triple Pole Breaker

The Blue Sea Systems 7271 is a 300A C-Series triple pole toggle DC circuit breaker in white.

Three hundred amps is the heaviest in this family, sized for inverters, bow thrusters and windlasses that pull hundreds of amps in short bursts. Sizing to those bursts rather than to continuous draw is what matters here, since a thruster's running current tells you very little about what it demands on startup.

It combines switching and over-current protection in one device, so the breaker is also the isolator for that circuit. There is no separate switch to install, and no separate switch to forget about when the circuit needs isolating for work.

The trip free design cannot be held closed after a trip, which removes the temptation to hold a breaker in to get a windlass through one more anchor recovery. That temptation is real on a foredeck in a rising wind, and the breaker tripped for a reason. Explore more marine circuit breakers.

• 300A, the heaviest in the C-Series triple pole family
• Size to startup surge, not running current
• Breaker and isolator in one device
• Trip free: cannot be held in through a fault