Can I use a Circuit Breaker instead of a MIDI Fuse?
This information is applicable to the following product ranges:
- BCDC In-Vehicle Battery Chargers
- Battery Management Systems
- Smart Battery Isolators
- Pure Sine Wave Inverters
This is a common question for customers installing our charging products, particularly when installing our BCDC In-Vehicle Battery Chargers, Battery Management Systems, Smart Battery Isolators and Inverters. While many would like to use circuit breakers, as these can be reset easily rather than having to replace a fuse, there are some important considerations when using them in high-current situations.
PROS AND CONS OF USING A CIRCUIT BREAKER
PROS
- Can be easily reset without needing replacement
- Clear visual indication when they have tripped
- Simple installation
CONS
- Prone to premature tripping under high current due to internal heat build-up (see hot circuit breaker pictured below)
- Can only handle about 90% of their rated current (e.g. a 50A breaker will handle 45A before tripping)
- Larger size compared to MIDI fuses


This diagram was created using a thermal imaging camera which visually shows the heat build-up in the circuit breaker.
In circumstances like this, they are only able to handle up to 80-90% of their rated current resulting in tripping prematurely under the circuit breaker’s max current rating.
WHY DO WE RECOMMEND USING A MIDI FUSE?
MIDI fuses provide more reliable protection for high-current applications and avoid many of the issues that circuit breakers face under heavy load.
PROS AND CONS OF USING A MIDI FUSE
PROS
-
Compact size, allowing multiple fuses to fit in the space of one circuit breaker
-
Easy visual identification when blows
-
Less susceptible to heat build-up
CONS
-
Must be replaced once blows
-
Spare fuses need to be available for quick replacement
If you prioritise long-term reliability, particularly in high-demand installations like inverters and charging systems, we recommend using MIDI fuses.

