Blue Sea Systems
Marine circuit protection, fuse holders, battery switches, busbars, and electrical distribution components designed for dependable boat systems.
Blue Sea Systems develops dependable AC and DC electrical products for marine and specialized vehicle applications. The brand is known for practical solutions across circuit protection, power distribution, switching, and system monitoring. The Common Ground Marine selection currently focuses on Blue Sea Systems marine fuses and fuse holders, including ANL, MEGA, MAXI, Class T, and MRBF formats. Compare voltage, amperage, fuse style, and holder compatibility to protect the complete electrical circuit.
Products from Blue Sea Systems
206 products
Blue Sea SystemsBlue Sea Systems M2 AC Multimeter
M2 AC multimeter, measures 2 voltages and 2 current circuits (or one 120/240V split-phase circuit), 50-250V, up to 300A total. OLED display, IP66.
SKU BLUE-1838
$269.50MSRP $323.40
Blue Sea SystemsBlue Sea Systems M2 DC Multimeter with SoC
M2 DC multimeter with state-of-charge tracking, measures 3 voltages and 1 current, 8-70V range, up to 500A with the included shunt. Programmable alarms.
SKU BLUE-1830
$254.80MSRP $305.76
Blue Sea SystemsBlue Sea Systems M2 OLED Tank Monitor
M2 OLED Tank Monitor, monitors up to 4 tanks, 1% resolution, auto-calibration for custom tank shapes. 80dB alarm, compatible with common senders.
SKU BLUE-1839
$254.80MSRP $305.76
Blue Sea SystemsBlue Sea Systems MAXI Fuse Block Ignition Protected 80A
Ignition-protected MAXI fuse block, 80A max, 32V DC max, screw terminals for 14-4 AWG wire. Replaces discontinued PN 5006. Fuse sold separately.
SKU BLUE-5006100
$30.80MSRP $36.96
Blue Sea SystemsBlue Sea Systems MAXI In-Line Fuse Holder
MAXI in-line fuse holder, 48A max, 32V DC max, supplied with a 5in #6 red lead wire and two adhesive-lined sealing shrink tubes. Fuse sold separately.
SKU BLUE-5068
$26.60MSRP $31.92
Blue Sea SystemsBlue Sea Systems ML-ACR Automatic Charging Relay - 12V DC 500A
ML-ACR, 12V DC, 500A continuous rating. Automatically manages charging between two large battery banks. Fully automatic, no manual override switch.
SKU BLUE-7620
$266.70MSRP $320.04
Blue Sea SystemsBlue Sea Systems ML-ACR Automatic Charging Relay - 24V DC 500A
ML-ACR, 24V DC, 500A continuous rating. Automatically manages charging between two large battery banks. Fully automatic, no manual override switch.
SKU BLUE-7621
$266.70MSRP $320.04
Blue Sea SystemsBlue Sea Systems ML-ACR Automatic Charging Relay with Manual Control - 12V DC 500A
ML-ACR, 12V DC, 500A continuous rating. Automatically manages charging between two large battery banks. Includes manual control override switch with LOCK OFF.
SKU BLUE-7622
$283.50MSRP $340.20
Blue Sea SystemsBlue Sea Systems ML-ACR Automatic Charging Relay with Manual Control - 24V DC 500A
ML-ACR Automatic Charging Relay with Manual Control - 24V DC 500A. Manual control switch provides an added level of safety allowing control with or without power, and offering LOCK OFF capability for servicing. Includes ML-Series Remote Control Contura Switch PN 2146.
SKU BLUE-7623
$233.10MSRP $279.72
Blue Sea SystemsBlue Sea Systems ML-RBS Remote Battery Switch with Manual Control - 12V DC 500A
ML-RBS Remote Battery Switch with Manual Control - 12V DC 500A, 300A continuous rating, 12V DC nominal control circuit. Bi-Stable coil, manual override knob included.
SKU BLUE-7700
$244.30MSRP $293.16
Blue Sea SystemsBlue Sea Systems ML-RBS Remote Battery Switch with Manual Control - 24V DC 500A
ML-RBS Remote Battery Switch with Manual Control - 24V DC 500A, 500A continuous rating, 24V DC nominal control circuit. Bi-Stable coil, manual override knob included.
SKU BLUE-7702
$244.30MSRP $293.16
Blue Sea SystemsBlue Sea Systems ML-RBS Remote Battery Switch with Manual Control Auto-Release - 12V DC 500A
ML-RBS Remote Battery Switch with Manual Control Auto-Release - 12V DC 500A, 500A continuous rating, 12V DC nominal control circuit. Auto-Releasing coil, manual override knob included.
SKU BLUE-7713
$282.10MSRP $338.52
Blue Sea SystemsBlue Sea Systems ML-Series Solenoid, Bi-Stable - 12V DC 500A
ML-Series Solenoid, Bi-Stable - 12V DC 500A, 500A continuous rating, 12V DC nominal control circuit. Bi-Stable coil, no manual override included.
SKU BLUE-7701
$227.50MSRP $273.00
Blue Sea SystemsBlue Sea Systems MRBF Terminal Fuse - 100A
MRBF Terminal Fuse - 100A. Requires the use of Terminal Fuse Blocks PN 5191 or PN 2151—do not mount the fuse directly to the battery terminal. Interrupt rating satisfies ABYC requirements for DC Main circuit protection on large battery banks.
SKU BLUE-5183
$16.10MSRP $19.32
Blue Sea SystemsBlue Sea Systems MRBF Terminal Fuse - 125A
MRBF Terminal Fuse - 125A. Requires the use of Terminal Fuse Blocks PN 5191 or PN 2151—do not mount the fuse directly to the battery terminal. Interrupt rating satisfies ABYC requirements for DC Main circuit protection on large battery banks.
SKU BLUE-5184
$16.10MSRP $19.32
Blue Sea SystemsBlue Sea Systems MRBF Terminal Fuse - 150A
MRBF Terminal Fuse - 150A. Requires the use of Terminal Fuse Blocks PN 5191 or PN 2151—do not mount the fuse directly to the battery terminal. Interrupt rating satisfies ABYC requirements for DC Main circuit protection on large battery banks.
SKU BLUE-5185
$16.10MSRP $19.32
Blue Sea SystemsBlue Sea Systems MaxiBus 250A BusBar Four 5/16in-18 Studs
MaxiBus 250A busbar, four 5/16in stud terminals, no screw terminals included on this bar. Rated 300V AC / 48V DC maximum for higher-current wiring.
SKU BLUE-2127
$58.10MSRP $69.72
Blue Sea SystemsBlue Sea Systems MaxiBus 250A BusBar Six 5/16in-18 Studs
MaxiBus 250A busbar, six 5/16in stud terminals, no screw terminals included on this bar. Rated 300V AC / 48V DC maximum for higher-current wiring.
SKU BLUE-2126
$74.20MSRP $89.04
Blue Sea SystemsBlue Sea Systems Mini OLED Ammeter, Yellow
Mini OLED ammeter, Yellow, monitors -100A to 100A DC range. Includes a 100A shunt. Mounts in a 1-1/8in hole, positive or negative side wiring.
SKU BLUE-1732
$79.80MSRP $95.76
Blue Sea SystemsBlue Sea Systems Mini OLED DC Voltmeter, Blue
Mini OLED DC voltmeter, Blue, monitors an 8-36V DC range. IP66 waterproof, mounts in a common 1-1/8in panel hole. Reverse polarity protected.
SKU BLUE-1733200
$43.40MSRP $52.08
Blue Sea SystemsBlue Sea Systems Mini OLED DC Voltmeter, Yellow
Mini OLED DC voltmeter, Yellow, monitors an 8-36V DC range. IP66 waterproof, mounts in a common 1-1/8in panel hole. Reverse polarity protected.
SKU BLUE-1733
$48.30MSRP $57.96
Blue Sea SystemsBlue Sea Systems MiniBus BusBar Cover for PN 2304 and PN 2305
Clear insulating busbar cover, fits Common 100A Mini BusBar PN 2304 (5-gang) and PN 2305 (4-stud). Snaps on with no tools to satisfy ABYC/USCG insulation requirements.
SKU BLUE-2713
$4.20MSRP $5.04
Blue Sea SystemsBlue Sea Systems Panel Mount AGC/MDL Fuse Holder Replacement Cap
Replacement cap for Blue Sea's panel-mount AGC/MDL fuse holder, PN 5021. This listing is the cap only — it does not include the holder body itself.
SKU BLUE-5022B
$2.87MSRP $3.44
Blue Sea SystemsBlue Sea Systems Panel Mount AGC/MDL Fuse Holder, Waterproof
Panel-mount AGC/MDL fuse holder, 20A max, waterproof knob design. Withstands salt spray, rain, and momentary immersion. Fuse sold separately.
SKU BLUE-5021B
$4.28MSRP $5.14
Choose the right Blue Sea Systems fuse
Start with system voltage, expected continuous current, conductor size, and the manufacturer's specified overcurrent protection. Then select the fuse family, amp rating, and a compatible holder or terminal block. Match the fuse to the holder and confirm the available interrupt rating and installation clearances.
Browse circuit protectionMarine circuit protection starts with the whole DC system
Blue Sea Systems offers several fuse formats for different installation and service requirements. Compare the electrical specification, physical format, and mating holder before ordering a replacement or building a new system.
- ANL, MEGA, MAXI, Class T, and MRBF fuse formats
- Fuse holders and terminal solutions for organized power distribution
- Guidance on voltage, amperage, conductor sizing, and compatibility
Frequently asked questions
What does Blue Sea Systems make?
Blue Sea Systems designs AC and DC electrical products for marine and specialized vehicle applications. The current selection includes marine fuses and a fuse holder for circuit protection and power distribution.
How do I choose a Blue Sea Systems marine fuse?
Confirm the system voltage, required amperage, conductor size, fuse type, holder compatibility, and the protection requirements specified by the equipment manufacturer. The fuse must be appropriate for the complete circuit, not just the load.
What is the difference between ANL, MEGA, MAXI, Class T, and MRBF fuses?
These are different fuse formats with different physical sizes, holders, ratings, and installation requirements. Use the product documentation and your system design to select the correct format and verify that the fuse and holder are a compatible pair.
Need a quote on Blue Sea Systems gear?
Tell us what you're building. Our team will spec the right kit for your install and send a written quote.
Why buy from us
We carry this brand because it earns its place on the boat.
Stocked for marine builds
We focus on parts that meet the conditions boats see — not just whatever ships fastest.
Engineering review on request
Send a parts list or a layout and we'll check it against your boat before you order.
Direct from our team
Pricing, availability, and product questions all go through the same people who build custom harnesses and panels.