Egis 3211-15 15A Single-Pole Marine Circuit Breaker

A circuit breaker isn't glamorous gear. But when a bilge pump seizes or a chafed wire shorts against the hull, this little Egis A-Series breaker is what stands between a nuisance and a fire. The 3211-15 is a 15-amp single-pole magnetic-hydraulic breaker in a black panel-mount toggle body, rated for both AC and DC, and built to shrug off the heat, cold, and vibration that live inside a boat.

Here's why the magnetic-hydraulic design matters on the water. A lot of cheaper breakers use a thermal element that reacts to heat, so they trip early when the engine compartment gets hot and trip late when it's freezing on a winter delivery. This one doesn't. It trips on actual current, and its behavior stays consistent from 40 below all the way up to 185 degrees Fahrenheit. So a breaker you set to protect a 15-amp circuit actually protects it, in July heat or January cold.

The dual AC/DC rating is the other thing that makes it handy. It's good for 277 volts AC and 80 volts DC, so the same part covers your 12- or 24-volt house circuits and any AC branch coming off an inverter or shore-power panel. Fifteen amps is a common size for a run of nav electronics, a washdown or livewell pump, cabin lighting, or an accessory circuit at the helm. Wire it in, and the toggle doubles as your on-off switch for that circuit. Flip it down to kill power when you're working on the gear, flip it up to bring it back.

When something does go wrong, it trips and stays tripped until you reset it by hand. No auto-cycling into a fault over and over. You find the problem, fix it, and flip the toggle back on. And because it's a manual-reset toggle, there's no separate switch to buy for that circuit.

Egis rates this one for a 5,000-amp interrupt at 277 VAC and 1,500 amps at 80 VDC. That high interrupt number matters more than it sounds. If you've got several batteries paralleled into a big house bank, a dead short can dump a staggering amount of current in a heartbeat, and a breaker with low interrupt capacity can weld itself shut instead of opening. This one is built to open cleanly and safely even on a large, high-energy system.

Installation is straightforward. It drops into any standard panel cut for A-Series or C-Series magnetic-hydraulic breakers, and the mounting screws come in the box. Connections land on No. 10-32 screw terminals, and Egis ships it with stainless-steel self-locking hardware so your ring terminals stay tight through years of pounding and vibration. That corrosion resistance from the stainless matters in a salt environment, and self-locking means you're not chasing a loose lug every haul-out.

One note on sizing. This is the 15-amp version of the Egis A-Series toggle breaker, and the family runs a wide range of amperages in the same body and panel footprint. So if you're building out a panel, you can mix breaker values across your circuits and still keep a clean, uniform look, with every toggle the same size and style. Match the amperage to the wire gauge and the load on each circuit, not to the biggest thing you might ever plug in. A breaker protects the wire, so a 15-amp breaker belongs on a circuit wired to carry at least 15 amps.

It's built to UL 1077 as a supplementary protector and rated for 6,000 electrical cycles at full load, so it holds up to real switching duty, not just sitting there waiting for a fault. Egis backs it with a 4-year warranty. It's a small part, but it's the kind of small part you want to get right. If you're rewiring a panel or adding a circuit and you want protection that behaves the same in any weather, this is an easy call.