When installing REDARC products such as BCDC chargers, Battery Management Systems, Smart Battery Isolators, or Inverters, circuit protection is essential.
While circuit breakers are convenient because they can be reset and provide a clear trip indication, they are prone to heat build-up, premature tripping, and can only handle about 80–90% of their rated current.
MIDI fuses, on the other hand, are compact, more reliable under high loads, less affected by heat, and easier to identify when blown, though they must be replaced. For long-term reliability in high-current applications, REDARC recommends using MIDI fuses over circuit breakers.
REDARC recommends seeking the support of a qualified auto electrician or technician.
Important
For your safety, REDARC recommends installation by a qualified auto electrician or technician. Our trusted REDNetwork is made up of professional auto electrical businesses certified by REDARC to install the complete of REDARC solutions. Find Your Local Installer
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 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.
