T Tocas 300A DC Circuit Breaker with 3/8" Studs — Manual Reset, IP67 Waterproof

The T Tocas E9 is a manual-reset 300 amp DC circuit breaker with 3/8" studs, IP67 waterproofing, and UL-rated rugged housing for trucks, RVs, marine and DC audio installations.

Built to replace a standard 300A fuse while providing a reusable, switchable reset option, the E9 combines high interruption capability with corrosion-resistant hardware and wide operating temperatures. Designed to work across 12–48V DC systems, this breaker is engineered for environments that demand reliable overcurrent protection and easy serviceability without needing frequent fuse changes.

How does the E9 protect my vehicle or boat electrical system?

The E9 interrupts dangerous overcurrent conditions by opening its contacts when current exceeds the designed threshold, then allows a manual reset once the fault is cleared. It is ignition protected so it can be installed in passenger compartments and engine bays where spark suppression is required.

• Rated 300 amps nominal with high interrupt ratings at 14V and 48V DC.
• Manual reset switch lets you restore power without replacing fuses.
• Ignition-protected design reduces risk when installed near fuel or ignition sources.
• Conforms to SAE and UL standards for safety and performance.

What electrical specifications and performance should I expect?

The E9 operates from 12V up to 48V DC and offers exceptionally high short-circuit interruption capabilities, making it suitable for heavy-current circuits like trolling motors, winches and audio amplifiers. Its thermal and magnetic elements handle short surges while tripping on sustained overloads.

• Works across 12–48V DC systems.
• High interrupt capacity: 2,500A at 14V DC, 1,500A at 48V DC.
• Operates reliably from -32°C to 82°C for varied climates.
• UL 94V-0 housing meets SAE J1625, J1171, UL1500 standards.

How do I mount and wire the 3/8" stud E9 breaker?

Mounting is straightforward: use the stainless steel 3/8"-16 studs and supplied insulators to secure the breaker to a suitable panel or busbar. The insulators protect the housing and prevent unintended grounding; tighten hardware to manufacturer torque specs and route cables with appropriate lugs for a durable installation.

• 3/8"-16 stainless steel studs for secure terminal connections.
• Insulator included to isolate stud from chassis ground.
• Use ring lugs sized for 3/8" studs and marine- or automotive-grade cable.
• Follow torque and mounting clearance recommendations in vehicle manuals.

Is the E9 durable for marine and outdoor use?

Yes—the unit is IP67-rated for waterproofing and built with corrosion-resistant components for harsh conditions. Its UL-rated, flame-retardant housing plus wide operating temperature range make it suitable for installations on boats, trucks, RVs, and other exposed systems.

• IP67 sealing protects against dust and temporary immersion.
• Stainless steel hardware resists corrosion in saltwater environments.
• Flame-retardant housing reduces fire risk under fault conditions.
• Designed for heavy-duty vehicle, marine and audio applications.

Who this is for: The T Tocas E9 300A breaker is intended for installers and DIYers who need a dependable, reusable high-current protection device for trucks, RVs, marine craft, trolling motors, DC audio systems, winches and other 12–48V applications. Choose this breaker when you want a UL-rated, ignition-protected solution that replaces disposable 300A fuses with a resettable safety device designed for demanding, wet, or corrosive environments.