Lewmar Circuit Breakers

Lewmar Circuit Breakers: Purpose-Built Marine Protection

Lewmar has been a trusted name in marine equipment since the company's founding in 1946, when Len Lewery started making Tufnol dinghy fittings and built what would become one of the leading marine equipment manufacturers in the world. That deep heritage in demanding on-water applications carries directly into every circuit breaker the brand produces — components designed not for a dry utility room, but for the wet, salt-laden, vibration-prone environment of a working boat.

Engineered for Windlass and Electric Winch Circuits

Lewmar circuit breakers are not general-purpose breakers repurposed for marine use. They are designed to be installed with Lewmar electric winches and windlasses, making them the natural first choice when building or servicing an anchoring system. Genuine Lewmar circuit breakers protect your windlass or electric winch, and these slow-blow circuit breakers are also suitable for use with Simpson Lawrence windlasses. The slow-blow characteristic is critical here: windlass motors draw heavy inrush current on startup, and a fast-trip breaker would nuisance-trip every time you deploy or retrieve your anchor.

Thermal, Trip-Free Design with Waterproof Construction

Lewmar's thermal circuit breakers use a proven thermally responsive bi-metal blade mechanism to sense overcurrent conditions. The "Trip Free" design cannot be held "ON" during a fault current condition, and the breakers are ignition protected — an essential safety requirement for enclosed engine spaces and fuel-adjacent installations. The Lewmar Thermal Circuit Breaker is a panel-mounted, waterproof breaker that works with DC systems up to 48V, covering modern dual-battery and lithium-based setups alike.

A 3000A interrupt capacity and waterproof protection against immersion to 1 meter for 30 minutes underscore just how seriously Lewmar takes the marine environment. Whether spray finds its way into a bow locker or a hatch leak drenches a panel, these breakers are built to keep working.

Clear Operation and Combined Switching

Lewmar thermal circuit breakers feature clear single-lever operation and combine switching and circuit protection into a single device, simplifying panel layout and reducing the number of separate components needed at the helm or breaker panel. Available in 70A, 90A, and 110A options designed specifically for use with Lewmar windlasses, plus higher-amperage panel-mount options that scale up to 200A for heavier duty applications, there is a Lewmar breaker suited to virtually every windlass or electric winch installation on the market.

The Right Breaker for the Right System

When sizing a replacement or specifying a new installation, matching the breaker amperage to your windlass model matters. Refer to your owner's manual to select the correct amperage. Lewmar's range spans compact short-body breakers for space-constrained panels all the way to full panel-mount assemblies with enclosures — giving installers the flexibility to spec the right solution whether they're retrofitting an older boat or commissioning a new build.

For boaters who have invested in a quality Lewmar windlass or winch system, pairing it with a genuine Lewmar circuit breaker ensures the entire electrical protection chain is designed to the same standard. Explore the full range of marine circuit breakers or learn more about the complete lineup on the Lewmar brand page.