Skip to content

Automotive Fuse Color Code Chart (ISO 8820 / SAE J1284)

Identify automotive blade fuse amperage ratings and continuous current limits by standard body color codes per ISO 8820 and SAE J1284.

140 views Free
Select Calculator Mode
4-Band Glass Fuse
-
1st Band (Digit)
2nd Band (Digit)
3rd Band (Multiplier)
4th Band (Type)
DETAILED SPECIFICATIONS
Decoded Value
-
Fuse Speed / Type
-
Fuse Classification
-
Standard
-

Glass Fuse Color Code Specifications

First / Second BandsRepresent the significant numerical values of the current rating. Decoded in Milliamperes (mA) or Amperes (A).
Multiplier BandMultiplies the significant digits to determine total current capacity. Accounts for fractional ratings with gold/silver bands.
Voltage / Speed BandTypically designates standard maximum working voltages (e.g. 125V or 250V) or speed characteristics (Fast-acting vs. Time-delay).
Single Dot MarkingCertain compact glass fuses use a single colored identifier indicating predefined current limits defined by regional manufacturers.

EIA/JEDEC Glass Fuse Marking Systems

Glass fuses protect delicate circuits against overcurrent conditions. To print indicators on clear curved glass envelopes, a durable color banding system conforming to EIA/JEDEC standards was introduced.

The sequence is read from left to right, starting with the band closest to one of the metal terminal caps. The calculated current is typically represented in milliamperes (mA) for lower limits, or directly in Amperes (A) for higher capacities.

Formulas & Calculation Logic

Current Rating (A or mA) = (Digit 1 × 10 + Digit 2) × Multiplier
Values below 1000 milliamperes are displayed in mA. Larger outputs automatically simplify to standard Amperes (A).

Step-by-Step 4-Band Example

Example Bands: Red, Red, Red, Gold
Step 1: Digit 1 (Red) = 2 | Digit 2 (Red) = 2. Combined Base = 22.
Step 2: Multiplier (Red) = x100. Base calculation: 22 × 100 = 2200 mA.
Step 3: Simplify notation: 2200 mA / 1000 = 2.2 Amps.
Step 4: Speed/Voltage marker (Gold) indicates Fast-Acting, rated up to 125V AC.

How to Correctly Read Glass Fuses

Locate the color bands aligned on the clear glass portion of the cylinder structure.
Identify the primary starting index, which usually sits shifted closely towards the left-most metal cap.
Input colors in order from left to right using our responsive dropdown grids.
Instantly verify critical safety thresholds including current levels and maximum voltage.

Frequently Asked Questions

1. Why do some glass fuses only have a single color dot?

A single dot represents a standardized commercial code indicating the rating directly. This approach is common on subminiature fuses where standard multi-band spacing isn't visually feasible.

2. What is the difference between fast-acting and slow-blow color markings?

Fast-acting glass fuses melt immediately when a current surge is detected. Slow-blow (time-delay) fuses withstand short starter-motor surges and are marked with a distinct fourth-band configuration.

3. Can I replace a glass fuse with a ceramic version of the same color code?

If physical sizes, voltage ratings, and amperage ratings match, ceramic is typically a safe upgrade as ceramic offers a higher bursting threshold in severe high-short-circuit currents.

Electronic Color Code Calculators, Fuse Color Code Chart, Transistor Color Code Chart, IC Color Code Chart, Diode Color Code Calculator, 3, 4, 5 & 6 Band Resistor Color Code Calculator, 3, 4 & 5 Band Inductor Color Code Calculator, SMD Resistor Code Calculator, SMD Capacitor Code Calculator, SMD Inductor Code Calculator, Ceramic Capacitor Code Calculator, Ceramic Capacitor Color Code with Voltage Rating, Ceramic Capacitor Color Code with Temperature Coefficient, Film Capacitor Code Calculator, Polyester Capacitor Color Code Calculator, Mica Capacitor Color Code Calculator, Tantalum Capacitor Color Code Calculator, Capacitor Capacitance Calculator, Capacitor Impedance Calculator, Capacitor Charge and Time Constant Calculator, Capacitor Stored Energy Calculator, Series and Parallel Capacitor Calculator, Interdigital Capacitor Calculator, Standard Capacitor Values Chart, Electrical Resistance Calculator, Series and Parallel Resistor Calculator, Resistor Ratio Calculator, Standard Resistor Value Calculator, LED Resistor Calculator, Ohm's Law Calculator, Inductor Coil Inductance Calculator, Series and Parallel Inductor Calculator, Inductor Stored Energy Calculator, Thermal Noise Calculator, Wheatstone Bridge Calculator, Electrical Wire & Cable Voltage Drop Calculator, Wire Size Calculator, Unit Conversion Calculator, Units of Pressure Converter
Select

Related Tools

About this tool

Automotive Fuse Color Code Chart (ISO 8820 / SAE J1284) is a free online calculator tool. Use it to get instant, accurate results for your electronics calculations.