Automotive Blade-Type Fuse Color Codes with Ampere Ratings

Types of Vehicle Fuses and Blade-Type Fuse Color Codes with Current Ratings

Vehicle and Automotive Fuses

A fuse in a vehicle is a safety device designed to protect the electrical circuits from damage caused by overcurrent or short circuits. It consists of a metal wire or strip that melts when excessive current flows through it, breaking the circuit and preventing further damage to connected components. The current ratings of these fuses are identified by different color codes, which are used to ensure the safe operation of electrical systems in vehicles, such as lights, audio systems, air conditioning, and electronic control units.

They offer overcurrent protection to prevents damage to circuits and components by interrupting the current flow during faults. These are disposable components and must be replaced after it blows. Automotive fuses come in various types and standardized ratings to suit different electrical requirements in the vehicle.

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Fuse Box in a Vehicle

The fuse box in a vehicle is a centralized hub where all the fuses are housed. It serves as the distribution center for electrical protection, allowing various circuits in the vehicle to operate safely. Modern vehicles typically have more than one fuse box, located in different areas for easy access and efficient circuit management.

Common Locations of Fuse Boxes:

• Engine Compartment: Protects circuits related to engine and drivetrain components, such as the radiator fan or fuel pump.
• Cabin (Under Dashboard): Covers interior electrical systems like headlights, stereo, and power windows.
• Trunk Area: In some vehicles, an additional fuse box may be located in the trunk to manage auxiliary systems.

What is a Blade-Type Fuse?

Blade-type fuses, also known as spade or plug-in fuses, are flat, plastic-encased fuses with two metal prongs or blades that fit into a socket. These types of fuses are widely used in automotive applications and low-voltage DC electrical systems due to their durability and standardized design.

Its Plastic housing encases the fuse element for protection and easy handling. The Metal Blades serve as terminals, ensuring a firm connection to the fuse box. Its Compact Size allows for use in tight spaces in modern vehicles.

The fuse Element is a a thin wire or strip inside the fuse housing designed to melt when the current exceeds the rated value.

Types of Blade-Type Fuses

Blade-type fuses come in various sizes and current ratings to accommodate different applications. Below are the common types categorized by size:

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Micro Blade Fuses (ATR/ATM)

The dimensions of micro blade fuses (also known as (ATR/ATM) are smallest among blade fuses, typically 9.1 mm in width and 8.7 mm in height. Micro blade fuses are available in Micro2 and Micro3 with current rating of 5-Amp to 30-Amp. They are used in compact electrical systems, such as modern car dashboards or infotainment systems.

Mini Blade Fuses (ATM)

The dimensions of mini blade fuses (also known as automotive Mini (ATM) are lightly larger than micro fuses, measuring about 10.9 mm in width and 16.3 mm in height. The dimensions of low-profile mini (APM/ATM-LP) fuse are even smaller than the mini blade fuse. These fuses came out in the early 1990s and are available with a current rating of 2-Amp to 40-Amp. They are commonly used in general automotive systems, including lights and wipers.

Standard Blade Fuses – (ATO/ATC)

Standard blade fuses are also known as Automotive C (ATC) or Automotive O (ATO) fuses invented by Littelfuse in the 1970s. The “C” and “O” indicates the “Close” and “Open” state of the fuse element inside the plastic housing. ATO/ATC fuses are available in a current rating of of 0.5-Amp to 40-Amp. The dimensions of the the most common blade fuse size are approximately 19.1 mm wide and 18.5 mm in height. Regular blade type fuses are used in a variety of vehicle systems, such as air conditioning and power windows.

Maxi Blade Fuses

The dimensions of the largest blade fuses are typically 29.2 mm wide and 34.3 mm in height. Maxi blade fuses are available in a current rating of of 20-Amp to 120-Amp. These heavy-duty fuses are used as a main fuse to protect high-current circuits like electric power steering or main power distribution.

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Blade-Type Fuse Color Codes

Blade-type fuses are color-coded for easy identification of their current ratings. Each color of the car fuse indicates the current value in amperes (sometimes printed on the flat head of the fuse). This standardization simplifies troubleshooting and replacement. Here is a common color code chart for Micro, Mini, Standard and Maxi fuses given in the tabulated form.

The color coding ensures that users can quickly match replacement fuses with their corresponding circuit requirements, reducing the risk of using incorrect ratings that might lead to damage.

For Reference: You may download the above table for later use given below as a chart.

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Current Rating in Amp of Color Coded Fuse

The following table shows the current rating in amperes with the associated color codes used for standard blade-type fuses.

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Smart Glow or Indicator Fuses

Besides the color-coded fuses often placed in inconvenient locations within a car, identifying a blown fuse can be challenging. To address this issue, “smart glow” fuses are used. These fuses feature a small built-in LED that illuminates when the fuse blows, making it easy to visually identify the faulty fuse. This simplifies troubleshooting and allows for quick replacement by simply inspecting the fuse box.

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