They are a variety of fuse sizes in use in automotive applications:

(image from Wikipedia by user Havarhen, CC-BY-SA-3.0 license)

My 1989 Opel Vectra used regular fuse size, but if I remember correctly my 2011 Toyota Yaris used low-profile mini fuses. I haven't yet taken a look at what fuses my 2016 Toyota RAV4 hybrid uses, but wouldn't be surprised to find if they also are low-profile mini fuses.

What is the reason for newer cars using smaller fuses in general? For example, Wikipedia says that those mini fuses were developed in 1990s. I don't think a fuse box with either fuse size uses too much space. Also, the material cost differences are minimal compared to the weight of the car. Serviceability seems to reduce little: the smaller the fuse is, the harder it is to change it and the easier it is to lose it if accidentally dropped, although I don't find those mini fuses overly difficult to change.

So, there must be some reason to use those small fuses. What is it?


Fuses keep changing, glass fuses used to be the standard and, on cars, there were only a few ratings 5A, 10A and usually 2 or 3 circuits that were fused.

Now circuits tend to be controlled by various computers : engine control unit, body control unit, gearbox ... the list goes on. But the circuits for these only require low currents 1, 2 or more amps so the fuses are now smaller but there are many more circuits that are protected.

Cars now have 2 or more fuse boxes - one under the bonnet and another under the dash. Given that if the older larger fuses were still in use for all circuits then the boxes would be much larger.

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    Good answer. I also believe this is a result of design having to be able to fit more fuses in tighter spaces. – CharlieRB Jul 17 '17 at 15:31
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    saving weight is one of the reasons for going to the micro3 fuse in the future. – Ben Jul 17 '17 at 16:53

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