Blue Sea Systems · 7748
Blue Sea SafetyHub 150 Fuse Block wiring diagram
Ten-circuit block combining four MIDI/AMI circuits up to 200A each, six ATC/ATO circuits up to 30A each and a negative bus. The single-feed drawing uses the 200A aggregate configuration; higher 350/600A configurations require the manufacturer's specified feeder arrangement. Fuses are separate.
- Compatible systems
- 12 V / 24 V
Wiring diagram
How the SafetyHub 150 is wired.
Open this example in Crimp to use your own parts and cable lengths. Review the assumptions and installation notes as you adapt the circuit.
Cable sizing for this example
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Installation notes
Before you install.
Open a question for model-specific guidance and sources.
Verified against the manufacturer's documentation (rev. 7748 SafetyHub 150 application diagram and current product specifications), checked 2026-10-01. Manufacturer documentation →
Which circuits does it contain?
The SafetyHub 150 contains four MIDI/AMI fuse positions up to 200 A each and six ATC/ATO positions up to 30 A each, plus a separate negative bus. Blue Sea’s specification does not describe a 150 A block: “150” is the product name. Fuses are purchased separately.
How much combined current is permitted?
Blue Sea gives 200 A with a 2/0 AWG feeder, 350 A with 4/0, or 600 A with two 4/0 feeds, under its stated 50°C ambient condition. The catalog represents the single-feed 200 A configuration. Adding individual slot ratings is not a valid aggregate rating, and a larger fuse cannot upgrade the feeder arrangement.
How are the terminals used?
Feed the positive input from the protected battery supply. Connect each branch to its correctly sized fuse position, and route returns to the negative bus. The primary studs use M8 hardware; published torques are 20.34 Nm for studs, 3.05 Nm for M5 screws, and 2.03 Nm for 8-32 screws. Identify the fastener before tightening.
Which circuits should stay live?
The application diagram shows alternatives before or after the battery switch. Bilge pumps and alarms can require independently protected, always-live feeds; other branches can follow the house switch. Verify the desired behavior by switching the system off. The planner labels MIDI and ATC branches separately; one block-wide fuse family would be wrong. Replace the sealed cover and labels after inspecting all connections.
How are the mixed fuse families recorded?
For each protected branch, select the correct cable fuse-type override: MIDI for a MIDI/AMI position or ATC for an ATC/ATO position. Then enter the installed fuse rating. A single block-wide family cannot describe both sections, so the slot label alone must not be treated as proof that the correct fuse type has been selected.
Technical reference
Specifications and terminal map.
Check the model, ratings and connection points against your own unit before choosing installation hardware.
Catalog specification
Ten-circuit block combining four MIDI/AMI circuits up to 200A each, six ATC/ATO circuits up to 30A each and a negative bus. The single-feed drawing uses the 200A aggregate configuration; higher 350/600A configurations require the manufacturer's specified feeder arrangement. Fuses are separate.
- Compatible systems
- 12 V / 24 V
Terminal map
Catalog connection points, current direction and planning limits. Check the manufacturer's pinout and connector ratings before installation.
BATT +
positive · input
NEG BUS
negative · bidi
MIDI 1
positive · output
MIDI 2
positive · output
MIDI 3
positive · output
MIDI 4
positive · output
ATC 1
positive · output
ATC 2
positive · output
ATC 3
positive · output
ATC 4
positive · output
ATC 5
positive · output
ATC 6
positive · output
RETURNS −
negative · bidi
Sources and sizing method
Equipment specifications. Model details, ratings and terminal roles come from the catalog. Check your unit’s label and current manufacturer documentation for its exact revision.
Example sizing. Cable labels apply to the connected example, not a fixed cable size for this component. Set your actual equipment, current, lengths and installation conditions in Crimp before choosing hardware.
Read how the sizing worksNext step
Plan your installation with SafetyHub 150.
Open this example as a new project, or add this component to your existing diagram. Use your equipment and cable lengths to review the sizing.
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