ANL, MEGA, CNN, MIDI? DC Fuses - what to use where?

What is a Fuse?
First of all, let's try to understand what is fuse is for. A fuse is an electrical safety device; it protects an electrical circuit against high currents. The fuse is placed in the supply cable to an electrical device. If a current flows through the fuse that is higher than its rating, the fuse will blow, and no more current will flow. This is what the fuse is supposed to do, to protect the device. Whatever the issue was that made the fuse blow, will have to be sorted out, after which the fuse can be replaced.

How to select the correct fuse
It is important to choose the correct, high quality DC fuse with the correct rating for its intended purpose. These are the characteristics to look out for:

      • Current rating: the fuse will need to match the current rating of the device(s) or cable, whichever is the lowest of the two.
      • Voltage rating: the voltage rating needs to be equal or higher than the expected maximum voltage. Most DC fuses are suitable for 12 and 24 V, but you need specific fuses for 48 V and higher.

Most components in your system will have a recommended fuse, so we recommend reading the product manuals to make sure you use the correct fuse.

Types of DC fuses
These are the DC fuses available on our site:

      • MIDI fuse 32 Vdc (for ≤ 24V systems), 60-200A, interrupting rating 2000A (click here)
      • MIDI fuse 58V (for ≤ 48V systems), 30-100A, interrupting rating 2000A (click here)
      • MEGA fuse 32 Vdc ((for ≤ 24V systems), 60-500A, interrupting rating 2000A (click here)
      • MEGA fuse 58V (for ≤ 48V systems), 125-300A, interrupting rating 2000A (click here)
      • ANL fuse 80 Vdc (for ≤ 48V systems) 300-500A, interrupting rating 6000A (click here)
      • CNN fuse 80 Vdc (for ≤ 48V systems) 325A, very fast acting fuse, interrupting rating 2500A (click here)

Inside Victron equipment, most MEGA and CNN fuses will be Littelfuse fuses; ANL fuses will generally either be Littelfuse, Bussman, or Zeeman fuses.

MID fuse 32 Vdc / 58 Vdc
The MIDI fuse is a slow, bolt-down fuse and has a smaller size and lower Amp ratings compared to the MEGA fuse, meant for M5 mm bolts. Use the 32 Vdc fuse for 12 and 24 Volts systems, and use the 58Vdc fuse for 48 V systems.
Victron MIDI fuse

MEGA fuse 32 Vdc / 58 Vdc
The MEGA fuse is the most commonly used fuse and is a slow, bolt-down fuse and has a larger size and higher Amp ratings than the MIDI fuse. The MEGA fuse is meant for M8 mm bolts. The MEGA fuse can be used fo fuse bigger loads, like inverter/charger, power distribution panels and solar charger in your system. Use the 32 Vdc fuse for 12 and 24 Volts systems, and use the 58Vdc fuse for 48 V systems. The MEGA fuse is used in the Victron Lynx Distributor.

Victron MEGA modula fuse holder 58V 32V

ANL fuse 80 Vdc
The ANL fuse is a bolt-down fuse and can be an alternative for the MEGA fuse and is a fast acting fuse. ANL fuses are good for any bigger loads such as Inverters, charge controllers, power distribution panels, or as the main battery / system fuse.
Victron ANL fuse
CNN fuse 80 Vdc
The CNN Fuse 325A/80V is a very fast acting main systems fuse (between the batteries and the rest of the system). The bolt-down fuse is meant for the Victron Lynx Shunt VE.Can. If the fuse blows, the Shunt will communicate this by showing a LED light and sends a message to the GX device.
Victron CNN fuse

For any additional questions, have a look at the community site of Victron:
Also read DC fuses and how to size them
Click here for SunStore's all Fuses and Fuse Holders

Source: Wiring Unlimited - Victron

Installations must be done by a qualified electrician/technician and must adhere to local wiring regulations and standards. Amperion - SunStore will not be held liable for any malfunctions as a result of incorrectly installed systems.