Sapphire Energy
DC Circuit Breakers (Marine Rated)
DC Circuit Breakers (Marine Rated)
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Heavy Duty DC Circuit Breakers
Protect your wiring and take control of your DC power system with these heavy-duty manual reset circuit breakers. Designed for demanding marine, RV and off-grid applications, they combine resettable overcurrent protection with a convenient manual switching function.
A practical choice for battery feeds, trolling motors, inverter circuits and other compatible DC equipment. Choose the available amp rating that matches your wiring and equipment requirements.
Why You’ll Love It
- Resettable protection: Restore power after correcting a fault without replacing a fuse.
- Manual switching: Conveniently disconnect the protected circuit when needed.
- Water-resistant construction: Manufacturer-rated IP67 protection against dust and water ingress.
- Ignition protected: Designed for demanding marine electrical installations.
- Built for repeated operation: Manufacturer-specified endurance of 10,000 switching cycles under rated test conditions.
- Secure connections: 5/16" terminal studs with stainless steel nuts and lock washers.
A manual reset breaker stays open after tripping until you reset it. This gives you the opportunity to identify and correct an overload or wiring fault before restoring power.
The manual switching function also lets you disconnect the circuit without removing a battery cable or pulling a fuse.
Choose the Right Amp Rating
Start with your equipment manufacturer’s recommended protection rating, then confirm that the cable, terminals and connections can safely support it. Cable length, installation temperature and continuous operating current all affect the correct selection.
A larger breaker does not increase the capacity of your wiring. Choose protection that allows normal operation while protecting the connected cable.
Send us your system voltage, equipment model, expected current, cable size and cable length. We can help you select a suitable breaker rating for your installation.
Typical Applications
- 12V and 24V marine and RV battery circuits
- Compatible trolling motors and marine accessories
- Inverter and auxiliary power feeds within the breaker’s ratings
- Camper, trailer and off-grid DC distribution
Technical Specifications
| Breaker Type | Type III — manual reset |
|---|---|
| Current Rating | As selected |
| Maximum Rated Voltage | 48V DC |
| Manual Switching | Yes |
| Terminal Thread | 5/16"-18 |
| Terminal Hardware | Stainless steel nuts and lock washers |
| Ingress Protection | IP67 — manufacturer specified |
| Ignition Protection | Manufacturer specifies SAE J1171 / UL 1500 |
| Interrupt Rating at 14V DC | 5,000A |
| Interrupt Rating at 24V DC | 3,000A |
| Switching Endurance | 10,000 cycles* |
| Housing Material | Thermoplastic — UL 94 V-0 flammability rating |
| Operating Temperature | −40°C to +85°C [−40°F to +185°F] |
*Manufacturer endurance testing is subject to current and voltage conditions. Thermal trip performance varies with ambient temperature. Manufacturer-stated standards and material ratings do not constitute a claim that the complete breaker is independently UL Listed.
Installation Notes
Install close to the battery or supplying busbar to minimize the length of unprotected wiring. Follow the marked LINE and LOAD connections, secure the breaker to a suitable mounting surface and use correctly sized cable lugs.
Keep terminal connections clean and secure, support cables against vibration and protect exposed connections from accidental contact. Use the specified terminal torque for the supplied breaker.
The 48V DC rating is a maximum voltage rating. A nominal 48V battery bank can exceed this while charging, so these breakers should not be selected for a 48V lithium bank. Always check the system’s highest operating voltage.
Frequently Asked Questions
Which amp rating should I choose?
Follow your equipment manufacturer’s recommended protection rating and confirm that your cable and connections are suitable. Allow for normal operating current, continuous loading and any startup surge.
Do not increase the breaker rating simply to stop repeated tripping. First check for overloads, undersized wiring, loose connections and excessive installation temperature.
Can I use it as a disconnect switch?
Yes. The breaker incorporates a manual switching function, allowing you to open the protected circuit without removing a fuse or disconnecting a cable.
Opening this breaker disconnects only the circuit wired through it. Other battery connections or charging sources may remain energized.
What happens when it trips?
The breaker opens the circuit and stays open until manually reset. Switch off the connected equipment, identify and correct the cause, and allow the breaker to cool before resetting.
If it trips again, investigate the circuit before restoring power. Repeated tripping can indicate an overload, fault or installation issue.
Will it trip immediately at its marked amp rating?
No. This is a thermal breaker with a time-current trip characteristic. A larger overload causes faster tripping, while a smaller overload can take longer.
Ambient temperature also affects performance. A hot enclosure can cause the breaker to trip at a lower current than it would in a cooler installation.
Is it suitable for marine use?
The breaker offers IP67 ingress protection and ignition protection to SAE J1171 / UL 1500. These features make it a practical option for suitable marine DC systems.
Mount it securely, protect exposed terminals and check connections periodically, particularly where salt, moisture and vibration are present.
Can I use it with lithium batteries?
Yes, where the system voltage, operating current and available fault current are within the breaker’s ratings. Lithium batteries can deliver substantial short-circuit current, so interrupt capacity matters as well as the selected amp rating.
Some installations require a higher-interrupt-capacity fuse at the battery, with breakers used on downstream circuits. These 48V DC-rated breakers are not suitable for nominal 48V lithium banks.
Are the terminal studs M8?
Sort of. The terminal thread is 5/16"-18 so M8 nuts won't fit correctly, but the diameter is close enough that M8 cable lugs will fit properly.
Do not use M10 (3/8") terminated cables with these breakers.
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