Description
Blue Sea 7138 Thermal Circuit Breaker 40A | Boat Supply Store
Safeguard your vessel's critical DC electrical systems with this robust 40 Amp thermal circuit breaker, rated for up to 48V DC and featuring SAE J1171 ignition protection for gasoline-powered craft. Engineered with a trip-free design and a manual reset function, it offers integrated switching and reliable protection across a -25°C to +82°C operating temperature range. Its 5000A @ 12V DC interrupt rating provides substantial fault current handling capability, making it ideal for installations in areas requiring strict ignition safety, such as engine compartments on offshore fishing boats operating in humid Gulf Coast conditions.
Key Features
- Combines switching and circuit protection for streamlined installations
- Meets stringent SAE J1171 external ignition protection requirements for gasoline engines
- Trip-free design prevents manual overriding of a tripped breaker
- Waterproof construction ensures durability in harsh marine environments
- Clear single lever operation provides intuitive control and status indication
- Ignition protected for safe use on gasoline-powered vessels
- Robust 5/16 terminals accommodate substantial wire gauges
- Recessed mounting holes offer a clean, professional installation appearance
Specifications
| Product Specifications | |
|---|---|
| Amp Rating | 40 Amp |
| Voltage Rating | 48V DC Max |
| Circuit Breaker Type | Type III (Switchable/Manual Reset/Trip Free) Thermal |
| Ignition Protection | SAE J1171 |
| Interrupt Rating | 5000A @ 12V DC |
| Operating Temperature Range | -25°C to +82°C |
| Case Material | Thermoset Polyester |
| Terminal Size | 5/16 |
Who This Is For
Marine enthusiasts and professional marine electricians who require dependable, integrated circuit protection and switching for 48V DC systems. Essential for gasoline-powered vessels needing SAE J1171 ignition protection.
How It Compares
| Feature | Blue Sea 7138 Thermal Circuit Breaker 40A | Blue Sea Systems 7139 187 |
|---|---|---|
| Amp Rating | 40 Amp | 50 Amp, 40 Amp |
| Voltage Rating | 48 Volts DC Maximum | 48 Volts DC Maximum, 12-24 Volts DC |
| Interrupt Rating (12V DC) | 5,000 Amperes | 5,000 Amperes, 2,500 Amperes |
| Ignition Protection | SAE J1171 | SAE J1171, SAE J1171 |
| Type | Type III - Switchable / Manual Reset - Trip Free | Type III - Switchable / Manual Reset - Trip Free, Thermal |
Common Concerns Answered
Are the terminals large enough for very thick marine-grade wires?
The 5/16" terminals offer robust connection points. For extremely thick gauge wires, ensure proper wire stripping and crimping techniques are employed for secure, reliable termination.
How does the 'trip free' mechanism work?
A 'trip free' circuit breaker cannot be manually held in the closed position when a fault current is detected; it will trip regardless of lever position to ensure circuit protection.
Is the price justified for a 40 Amp breaker?
The price reflects the integrated switching functionality, SAE J1171 ignition protection, trip-free design, and robust waterproof construction specifically engineered for demanding marine applications and enhanced safety.
Frequently Asked Questions
What is the interrupt rating of the Blue Sea 7138 circuit breaker?
The Blue Sea 7138 circuit breaker has an interrupt rating of 5000 Amperes at 12V DC.
Is the Blue Sea 7138 ignition protected?
Yes, the Blue Sea 7138 is ignition protected and meets SAE J1171 external ignition protection requirements.
What is the voltage rating of the Blue Sea 7138 circuit breaker?
The maximum voltage rating for the Blue Sea 7138 circuit breaker is 48 Volts DC.
Can the Blue Sea 7138 be used on gasoline-powered boats?
Yes, due to its SAE J1171 ignition protection, the Blue Sea 7138 is suitable for use on gasoline-powered boats.
What is the operating temperature range for the Blue Sea 7138?
The Blue Sea 7138 operates reliably within a temperature range of -25°C to +82°C.
