ATC / ATO blade fuse (standard automotive)
The standard automotive blade fuse used in most cars, trucks, and SUVs from the 1990s onward. 19.1 mm tall with two flat blade terminals. Color-coded by amperage. ATC (closed body) and ATO (open body) are interchangeable.
Specifications
| Property | Value |
|---|---|
| Standard designation | ATC / ATO (SAE J1284) |
| Overall height | 19.1 mm |
| Width | 18.0 mm |
| Blade spacing | 5.08 mm (0.2 in) |
| Voltage rating | 32 V DC (automotive) |
| Amperage range | 1 A to 40 A |
ATC vs ATO
ATC has a fully enclosed plastic body; ATO has an open body that exposes the element. Both have identical dimensions and blade spacing — they are fully interchangeable in the same fuse holder.
Color code (standard amperage)
| Color | Amperage |
|---|---|
| Gray | 2 A |
| Violet / Purple | 3 A |
| Tan / Pink | 5 A |
| Brown | 7.5 A |
| Red | 10 A |
| Blue | 15 A |
| Yellow | 20 A |
| Clear / White | 25 A |
| Green | 30 A |
| Orange | 40 A |
Common applications
- Passenger vehicle fuse boxes (underdash and engine bay)
- Aftermarket car audio systems
- Recreational vehicles (RVs, boats with 12 V systems)
- Fused distribution blocks in custom vehicle wiring
How to check if a blade fuse is blown
Look through the translucent plastic body. The metal element (a bridge shape) will be visibly broken or melted if blown. For a definitive check, use a multimeter set to continuity mode — place probes on each exposed blade tip.
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