351 High Amp Circuit Breaker: IP67 Auto Reset Protection from 25A to 300A
High-current accessory and auxiliary circuits can get expensive fast when something goes wrong. Winches, compressors, inverters, lift gates, and battery feeds all need protection that can survive vibration, moisture, and real-world wiring.
The OptiFuse 351 Series is a heavy-duty, waterproof high-amperage circuit breaker commonly used in RVs, marine craft, emergency vehicles, and heavy-duty trucks. It is often installed close to the battery as a primary source of power protection, and the elongated body makes it easier to land heavy-duty lugs.
Key specs at a glance
- Current range: 25A to 300A
- Reset type: Type I (automatic reset)
- Ingress rating: IP67 sealed construction
- Terminations: 3/8-16 stud terminals for ring lugs
Voltage and interrupt ratings
Up to 48VDC, with interrupt ratings listed on the datasheet (including 3000A @ 30VDC and 1500A @ 48VDC).
Why engineers pick the 351
- Auto reset is useful when the breaker is not easy to reach, since it resets after cooling once the fault clears.
- Sealed housing helps in wet, dusty, and splash-prone installs.
- The published interrupt rating is positioned to meet ABYC requirements for certain battery main protection scenarios.
Typical applications
The 351 is commonly used for high-current DC branches and battery-adjacent protection such as:
- RV and marine battery feeds / auxiliary distribution
- Winches, compressors, hydraulic pump motors, lift gates
- DC inverters and high-current accessory distribution
- Emergency / fleet vehicle add-ons where sealing + durability matter
Mounting and wiring notes
A few practical details help keep high-amp installs reliable:
- Mount close to the source (often near the battery) to minimize the length of unprotected cable.
- Use properly sized ring lugs on the 3/8”-16 studs, and torque within the manufacturer guidance (stud torque and mounting torque are called out on our 351 datasheet).
- Provide strain relief so the cable weight/vibration isn’t loading the studs.
- Route and protect the cable against chafe (loom/grommets) and keep it away from high-heat sources.
How the 351 compares to other high-amperage options
High-amp fuses (ANE / MIDA / MGGA) | One-time device, must be replaced after it blows
You don’t want automatic re-energizing after a fault; you want a clear “replace + inspect” step
You want automatic restoration after a temporary overload and easier uptime
Manual-reset breakers (see our 353 high-amp) | Trips and stays open until someone resets it
You want “trip and stay off” until a person inspects the circuit
The circuit may see brief overloads and the breaker is hard to access
Need help selecting the right protection for your circuit? See our Fuse Selection Guide for complete context.
Sebastian Castañeda is a circuit protection specialist and technical writer with application-focused experience in technical support and custom protection design. He contributes practical, application-driven insights to the OptiFuse Blog.