The Fuse Rating Calculator helps determine the appropriate fuse size based on continuous load current and
optionally wire gauge and system voltage. This helps protect your wiring from overheating and prevents equipment damage.
How Fuse Sizing Works
Fuse rating is normally based on continuous current plus a safety margin to handle short surges. Undersized
fuses trip frequently while oversized fuses fail to protect the wire from excessive heating.
Common rule: Fuse = Continuous Current × 1.25
Why Correct Fuse Size Matters
- Protects wiring from heat
- Prevents cable insulation damage
- Avoids equipment burnout
- Prevents fire hazards
Where This Calculator Is Useful
- Battery circuits
- Solar DC wiring
- eBike power lines
- Automotive DC systems
- 12V/24V/48V installations
Frequently Asked Questions
Q: What fuse rating should I choose?
A typical recommendation is continuous current multiplied by 1.25 to avoid nuisance tripping.
Q: Should fuse protect the wire or the device?
A fuse protects the wire from overheating, not just the connected device.
Q: Can I use a bigger fuse to avoid tripping?
No, oversized fuses can allow dangerous wire temperatures and pose a fire risk.
Q: Does system voltage matter?
Voltage helps determine fuse voltage rating class, but current decides fuse size.
Q: Is wire gauge required?
No, but entering wire gauge helps verify that the fuse is properly matched to the conductor size.
