Fuse reference
Fuses are protective devices that interrupt a circuit when current exceeds a safe level. The physical type must match the fuse holder; the amperage rating must match the circuit specification. Never substitute a higher-rated fuse to "fix" a blowing fuse — that masks a fault.
Common fuse types
| Type | Form factor | Dimensions | Common use |
|---|---|---|---|
| AGC | Glass tube | 6.35 × 31.75 mm | Electronics, appliances, fuse panels |
| ATC / ATO | Blade (standard) | 19.1 mm tall | Automotive fuse boxes (most cars 1990s–present) |
| Mini blade (ATM) | Blade (small) | 10.9 mm tall | Modern automotive, motorcycles, SUVs |
| Maxi blade (APX) | Blade (large) | 29.2 mm tall | High-current automotive circuits (20–100 A) |
Comparisons
Critical safety rule
Always replace a fuse with the same type and same amperage rating. The physical type must fit the holder exactly. The amperage is circuit-specific — it is set by the circuit designer, not by preference.
Reading a fuse
- Glass tube (AGC): amperage is printed on the metal end cap, e.g. "5A" or "5 Amp Slo-Blo".
- Blade fuses: amperage is printed on the plastic body and color-coded (see individual type pages).
- Blown indicator: glass fuses show a visibly broken wire. Blade fuses show a melted bridge visible through the translucent plastic body.