Campervan 12 V distribution: fuses, busbars and three layouts
SpaziouSpaziou Technical · Protection and distribution
Campervan 12 V distribution: fuses, busbars and blocks.
A well-organised installation separates high-current main distribution of the small-load branches. Not all fuse blocks do the same job.
Three models · three functions
High current, mixed systems or load branches.
Victron Lynx Distributor
Positive and negative busbars with four fuse positions. Designed to integrate large loads and sources within the Lynx system.
- Circuits
- 4 fused DC connections
- Fuse
- MEGA format according to the manual
- Busbar
- Positive + negative
- Nominal
- 1,000 A Lynx system; actual design is limited by its most restrictive component
- Indicators
- Status LEDs; operation depends on the Lynx power supply/design described by Victron
- Profile
- Inverter/charger, MPPT, large branches and modular Victron systems
Blue Sea SafetyHub 150 · 7748
Combines four MIDI/AMI positions for larger loads and six ATO/ATC positions for small circuits in one block, plus a negative bus.
- Circuits
- 10
- High current
- 4 × AMI/MIDI
- Branches
- 6 × ATO/ATC
- Voltage
- 12 / 24 / 32 V DC
- Negative busbar
- Yes
- Protection
- Sealed cover; marine certifications published by the manufacturer
- Profile
- For combining large and small protective circuits close to the battery
Blue Sea ST Blade 5031
12-circuit ATO/ATC block with negative bus. More suitable as secondary distribution for lights, pumps, USB and electronics than for powering large inverters.
- Circuits
- 12
- Fuses
- ATO/ATC
- Published maximum
- 100 A per block / 30 A per circuit, subject to appropriate cables and fuses
- Voltage
- Up to 32 V DC
- Negative busbar
- Yes
- Weight
- ≈0.29 kg
- Profile
- Low- and medium-current load branches
They are not direct replacements
The role each one plays.
| System | Diagram area | Fuse type | Negative busbar | When does it make sense |
|---|---|---|---|---|
| Lynx Distributor | Main distribution / high current | MEGA | Yes | Large systems, inverter, MPPT and Lynx layouts |
| SafetyHub 150 | Main + branches | MIDI/AMI + ATO/ATC | Yes | Combine two protection levels in limited space |
| ST Blade 5031 | Secondary distribution | ATO/ATC | Yes | Lights, pumps, USB, electronics and other small branches |
Design sequence
Protect the cable leaving each source first.
Buy by function, not amperage
Amazon product references for building and protecting the circuit.
MEGA / ANM · exact ASINVEXUNGA fuse holder + MEGA 125 A
Budget example showing the MEGA/ANM fuse and holder format. 125 A is not a universal recommendation: use it only if your cable, equipment and design require that rating.
Mounting · terminalsHX-50B · crimping tool 6–50 mm²
For battery and distribution terminals in common cable sizes. A poor crimp can add resistance and heat even to a good cable.
Cable · exact ASINJatilEr · 16 mm² · 50 cm · M8
Preassembled red/black pair for very short runs. Use only if Cable Lab and the equipment manual allow 16 mm² and the 50 cm length genuinely fits.
Isolation switch · exact ASINVictron Battery Switch · 275 A
Manual switch to isolate the battery bank during maintenance or storage. Victron states 275 A continuous and systems up to 48 V; it does not replace a fuse.
Cable · exact ASINDIHOOL · 25 mm² · 50 cm · M8
An intermediate cable size for short high-current runs. Do not choose it because it “looks thick”: use it when Cable Lab and the manual specify 25 mm² or less and its current-carrying capacity is sufficient.
Cable · exact ASINDIHOOL · 35 mm² · 50 cm · M8
For circuits requiring 35 mm² by calculation. The photo shows the official SWSC family; confirm the 50 cm/M8 version and equipment limit before buying.
Complete the system
Distribution, charging and monitoring belong together.
Spaziou Lab
Technical references, not universal recipes.
Functions, fuse formats, circuit counts and limits come from official Victron and Blue Sea documentation consulted in September 2026. We do not claim physical tests of these three systems or copy fuse values between installations without calculation.
