Automotive Fuse Types Explained — Mini Blade, Standard and Micro

Why Automotive Fuses Matter

Every electrical circuit in your vehicle is protected by a fuse. When a circuit draws more current than it should — due to a fault, short circuit, or overload — the fuse blows before the wiring can overheat and cause a fire. A fuse is a sacrificial component designed to fail safely.

The Three Main Blade Fuse Types

Mini Blade Fuses (ATC/ATO) — The Most Common Type

Mini blade fuses are the most widely used fuse type in modern Australian vehicles, found in the main fuse box of most cars built from the 1980s onward.

• ATC = covered (closed bottom)
• ATO = open bottom
• Size: 19mm tall x 11mm wide
• Amp range: 1A to 40A
• Colour coding: Tan=5A, Brown=7.5A, Red=10A, Blue=15A, Yellow=20A, Clear=25A, Green=30A

Standard Blade Fuses — Larger Circuits

Larger than mini blade fuses, used in older vehicles and high-current applications like main supply fuses, air conditioning, and headlight circuits.

• Size: 29mm tall x 19mm wide
• Amp range: 5A to 40A

Micro Blade Fuses (ATM) — Newer Vehicles

Increasingly common in European and Japanese vehicles from the 2000s onward. Not interchangeable with mini blade — the housings are different sizes.

• Size: 15.5mm tall x 10mm wide
• Amp range: 2A to 30A

How to Choose the Right Amp Rating

Never replace a fuse with a higher amp rating. If a 10A fuse keeps blowing, the answer is not to fit a 15A fuse — it's to find what's causing the overload.

1. Check the label inside your fuse box cover — it lists every circuit and its correct fuse rating
2. Check your vehicle's owner's manual
3. Replace with the exact same amp rating as the blown fuse

Inline Fuse Holders — For Add-On Circuits

When you add an aftermarket accessory — a dash cam, driving lights, fridge, or USB outlet — the new circuit needs its own fuse. An inline fuse holder is installed in the positive wire between the battery and the accessory.

• Match the fuse holder to the type of fuse you're using
• Rate the fuse at the minimum needed to protect the wire
• Install the fuse holder as close to the battery as possible

Shop Fuses and Fuse Holders at Auto Relay

Auto Relay stocks mini blade fuse holders, inline ATC/ATO fuse holders, and a 180-piece fuse assortment kit covering all three blade fuse types, with fast shipping across Australia.