Heavy-duty DC circuit protection for marine, RV & off-grid systems

The Victron Energy MEGA-Fuse is the industry-standard bolt-down fuse for protecting high-current DC wiring in 12V, 24V, and 48V battery systems. Whether you're building out a Victron Lynx distribution system on your boat, wiring an inverter/charger in your RV, or protecting battery banks in an off-grid cabin, these fuses are the reliable overcurrent protection your system needs.

Available in amperage ratings from 40A to 500A and voltage ratings up to 32V, 58V, or 80V, Victron MEGA-Fuses cover virtually every DC fusing requirement in marine, mobile, and off-grid power installations. Sold in convenient 5-packs (or single-piece for select 58V models) so you have spares on hand when it matters.

Why use Victron MEGA-Fuses?

Every DC circuit needs overcurrent protection. Without a properly rated fuse between your battery bank and connected equipment, a short circuit or fault can cause cable overheating, equipment damage, or fire. MEGA-Fuses (also known as AMG-style fuses) are specifically designed for the high-current, heavy-gauge wiring found in battery-based power systems — exactly the kind used in Victron inverter, charger, and DC distribution installations.

Low voltage drop & cold resistance — minimal energy loss at the fuse, keeping your system efficient
Visual blow indicator — clearly see when a fuse has tripped without a multimeter
Bolt-down M8 terminals — secure, vibration-resistant connections ideal for boats, RVs, and vehicles
High interrupt capacity — safely breaks the circuit under heavy fault-current conditions
Direct fit for Victron accessories — designed for the Victron Modular MEGA Fuse Holder, Lynx Shunt, and Lynx Distributor

How to choose the right MEGA-Fuse

Selecting the correct fuse involves two decisions: voltage rating and amperage rating.

Step 1 — match the voltage rating to your battery system:

32V fuses for 12V and 24V battery systems (most common for boats and RVs)
58V fuses for 48V battery systems
80V fuses for 48V systems where higher voltage headroom is needed (Victron's newer ceramic design)

Step 2 — size the amperage to your circuit:

A common rule of thumb is to size the fuse at roughly 1.25 to 1.5 times the maximum continuous current of the device being protected. For example, a Victron MultiPlus-II 12/3000 draws up to 250A at full load, so a 300A or 400A MEGA-Fuse would be appropriate. Just as important, choose a wire size rated for at least the fuse amperage you select. Always follow the manufacturer's fusing recommendations for your specific equipment.

Frequently asked questions

What's the difference between MEGA and MIDI fuses?
MEGA-Fuses (AMG style) are larger and handle higher amperages, typically 40A to 500A. MIDI fuses are a smaller form factor for lower-current circuits, usually 30A to 200A. If you're fusing a main battery-to-inverter cable, you almost always need a MEGA. For smaller branch circuits like solar charge controllers or DC-DC chargers, a MIDI fuse may be the better fit.

Can I use these on a 48V system?
Yes, but you need the correct voltage rating. The 32V fuses are only rated for 12V and 24V systems. For 48V battery systems, choose the 58V or 80V rated variants. Using a fuse with a voltage rating below your system voltage is a safety hazard, as the fuse may not interrupt the circuit properly under fault conditions.

How do I know when to replace a MEGA-Fuse?
Victron MEGA-Fuses have a visual blow indicator — a small window on the fuse body that shows whether the element is intact. If the indicator shows a break, or if you've lost power on a circuit and suspect a blown fuse, test with a multimeter for continuity. It's smart to keep spares on board, which is why most of these are sold in 5-packs.

Do I need one fuse per battery or one per circuit?
Each high-current circuit should have its own fuse. In a typical Victron system, you'll have a MEGA-Fuse between the battery bank and each major load (inverter/charger, DC distribution bus, etc.). If you're using a Victron Lynx Distributor, each output position takes its own MEGA-Fuse.

Blue Marine is an authorized Victron Energy dealer — ships brand-new with the full 5-year Victron warranty, free shipping, and local pickup available.

Fuses and Fuse Holders