Bussmann 150A Type III Circuit Breaker — Flush-Mount, Waterproof for Marine & RV

The Bussmann Series CB185 150A Type III is a flush-mount, waterproof high-amperage circuit breaker engineered to protect auxiliary, accessory and multi-battery charging circuits in trucks, RVs, buses and marine craft.

This genuine Bussmann circuit breaker combines a sealed, ignition-protected housing with a robust trip rating to manage heavy auxiliary loads and battery-charging paths. Designed for flush-panel installations, the CB185 Type III fits vehicle and marine control panels while meeting SAE J1171 ignition-protection requirements. It’s commonly used with battery isolators and multi-battery systems to prevent overloads and to protect wiring and components used in demanding transportation and recreational environments.

How does the CB185 protect my vehicle or boat electrical system?

The CB185 interrupts excessive current before heat or wiring damage can occur, preserving downstream components and batteries. Its sealed housing and Type III construction are intended for environments where moisture, vibration and exposure are common.

• 150A trip rating suited for heavy auxiliary circuits and charge feeds;
• Fast response to sustained overloads to limit wiring heating;
• Sealed, waterproof enclosure reduces corrosion risk in damp locations;
• Ignition-protected per SAE J1171 to reduce spark/ignition hazards around fuel systems.

Where is this circuit breaker typically installed and how is it mounted?

The CB185 is designed for flush-panel mounting in dashboards, equipment panels and switchboards of commercial vehicles, RVs and boats. Its form factor lets it sit neatly in control panels while maintaining accessibility for inspection and reset operations.

• Flush-mount face for a low-profile, finished panel appearance;
• Commonly used in auxiliary circuits, battery charging lines and isolator outputs;
• Suitable for trucks, buses, RVs, trailers and marine applications;
• Panel cutout and mounting hardware allow secure installation against vibration.

What performance and safety standards does the CB185 meet?

The CB185 adheres to industry safety expectations for ignition protection and marine/vehicle environments. Its sealed construction and Type III designation make it appropriate where moisture and contaminants are present.

• Complies with SAE J1171 for ignition protection to reduce spark risk near fuel-air environments;
• Waterproof, sealed housing to resist ingress and corrosion in marine or wet conditions;
• Robust contact and trip mechanism for consistent performance under repeated use;
• Manufactured and labeled as a genuine Bussmann part for traceability and quality assurance.

How do I choose the right breaker size and integrate the CB185 with battery isolators?

Select a breaker rating that matches the maximum expected continuous load plus a margin for startup currents. When used with battery isolators or multi-battery charging systems, place the CB185 on the charge feed or isolator output to protect wiring and batteries from sustained overcurrent.

• Confirm 150A rating suits the circuit’s expected peak and continuous currents;
• Match wiring gauge and conductor insulation to breaker capacity for safe operation;
• Locate breaker close to the battery or charge source to protect the length of conductor;
• Coordinate with isolator wiring so the breaker protects battery and accessory feeds as intended.

Who is this for: The Bussmann CB185 150A Type III circuit breaker is ideal for fleet technicians, RV owners, marine electricians and DIY vehicle upfitters who need a durable, ignition-protected, flush-mount protective device for high-current auxiliary and charging circuits. If you install or maintain multi-battery systems, battery isolators, or heavy accessory loads on trucks, buses, RVs or boats and require a sealed, panel-mount breaker with recognized ignition-protection compliance, the CB185 is a practical choice.