What fuse does a power inverter use?
Power inverters require an in-line fuse on the DC cable within 18″ of the battery. Small inverters (under 400 W) use a MAXI blade fuse at 30–60 A. Large inverters use ANL bolt-down fuses at 80–300 A depending on output.
Why fusing the DC side matters
The DC cable between your battery and inverter carries far more current than the AC output because of the voltage conversion. A 300 W inverter on a 12 V system draws 25 A DC. An unfused or improperly fused cable can overheat and cause a fire — the fuse protects the cable, not the inverter.
Fuse sizing by inverter wattage
| Inverter wattage | Max DC draw (12 V) | Recommended fuse | Fuse type |
|---|---|---|---|
| 150 W | ~15 A | 20 A | MAXI blade |
| 300 W | ~30 A | 40 A | MAXI blade |
| 400 W | ~40 A | 50 A | MAXI blade |
| 600 W | ~60 A | 80 A | ANL |
| 1000 W | ~100 A | 125 A | ANL |
| 2000 W | ~200 A | 250 A | ANL |
Rule of thumb: fuse at 125–150% of the maximum DC current draw. Always refer to the inverter's installation manual for the manufacturer's recommended value.
Fuse types by inverter size
MAXI blade — available at 20–100 A, fits standard MAXI fuseholders. Good for inverters up to 400–600 W at 12 V.
ANL bolt-down fuse — a large rectangular fuse that mounts in a bolt-down holder directly on the cable. Used for high-current inverters and available in 80–350 A. Not covered on this site as it is primarily a DC power distribution component.