Applications of Ceramic Automotive Fuses ！

January 27, 2026

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Applications of Ceramic Automotive Fuses

 
Ceramic automotive fuses are core components for automotive circuit protection, featuring excellent high-temperature resistance, vibration resistance, arc extinguishing performance and electrical insulation. These characteristics make them ideal for the harsh working conditions of automobiles (high temperature, strong vibration, dust, oil fume) such as the engine compartment and chassis. They are widely used in low-voltage (12V/24V) and medium-low voltage auxiliary circuits of passenger cars, commercial vehicles and new energy vehicles (NEVs). Special ceramic fuses are also applicable to the low-voltage power distribution system of NEVs. Their core function is to melt quickly in case of circuit overcurrent or short circuit, protecting wiring harnesses, electrical equipment and power supply systems from fire or burnout.
 
Their applications cover the full range of automotive circuits including powertrain, body, chassis, intelligent electronics and NEV auxiliary systems. According to vehicle types and circuit categories, the core application scenarios are classified as follows, and ceramic fuses with different amperages (A) are matched with electrical equipment of corresponding power:
 

1. Core powertrain-related circuits in the engine compartment (the primary application scenario)

 
The engine compartment is the area with the highest temperature (engine waste heat, exhaust system), strongest vibration and most complex environment in a car. Plastic fuses are prone to thermal deformation and insufficient arc extinguishing capacity, so ceramic automotive fuses are almost exclusively used here, which is also their largest consumption scenario:
 
  1. Starting system: Starter power supply circuit, starter relay control circuit. High-current ceramic fuses (30A~80A) are adopted to prevent short circuit caused by starter jamming.
  2. Charging system: Generator output circuit, battery charging and discharging circuit, which protects the generator and battery from damage due to overcharging or short circuit.
  3. Fuel/air intake system: Fuel pump, fuel injector, electronic throttle, intake manifold flap control circuit, ensuring the stable fuel supply and air intake of the engine.
  4. Cooling system: Electronic cooling fan, thermostat control circuit, preventing overcurrent caused by cooling fan jamming and avoiding engine overheating.
  5. Ignition system (for fuel vehicles): Ignition coil, spark plug power supply circuit, matched with medium-current ceramic fuses (10A~20A).
  6. Engine electronic control: ECU (Engine Control Unit) power supply circuit, sensor power supply (crankshaft position, camshaft position, oxygen sensor, etc.), protecting core electronic control components.
 

2. Body electrical systems (preferred for high-temperature/high-power branches)

 
In body circuits, ceramic fuses are used for high-power, high-working-temperature branches close to the engine or exhaust system, while plastic fuses can be used for low-power indoor branches. The core applications are:
 
  1. Air conditioning and heating system: Air conditioning compressor clutch, blower, heating resistor, condenser fan circuit, mostly with medium and high current (15A~40A). Ceramic fuses can withstand the instantaneous high current of air conditioning compressor startup and remain stable in high-temperature environments.
  2. Lighting system (high-power external lamps): Main power supply circuits of high beam, low beam, turn signal, brake light, fog light and daytime running light, especially the ballast/driver module circuits of xenon/LED headlights, avoiding circuit damage caused by instantaneous inrush current during lamp startup.
  3. Power supply for high-power electrical accessories: Power supply circuits of electric windows, electric sunroofs, electric seats, electric side mirrors and windshield wipers (especially rear window defrosters with high power consumption), which are resistant to frequent on-off current impacts of electrical accessories.
  4. Body control system: BCM (Body Control Module) main power supply circuit, central locking, keyless entry and anti-theft system power supply circuit, protecting the core control unit of body electrical appliances from overcurrent damage.
 

3. Chassis and safety system circuits (high-reliability demand scenarios)

 
Chassis circuits are related to vehicle driving safety, and ceramic fuses are used for their high structural stability and reliable fusing performance to avoid circuit failure affecting safety:
 
  1. Brake system: Anti-lock braking system (ABS), electronic stability program (ESP) and electronic parking brake (EPB) control module power supply circuits, which are key safety components and require high-reliability ceramic fuses for protection.
  2. Steering system: Electric power steering (EPS) control circuit, hydraulic power steering pump power supply circuit, preventing steering failure caused by circuit overcurrent.
  3. Suspension system: Active suspension, air suspension control module and air pump power supply circuit (for medium and high-end models), protecting the precision control components of the suspension system.
  4. Passive safety system: Airbag control unit (ECU) power supply circuit, seat belt pretensioner power supply circuit, ensuring the normal trigger of safety components in case of accidents.
 

4. Intelligent electronic and infotainment system circuits (partial high-power branches)

 
With the intellectualization of automobiles, the load of on-board electronic systems is increasing. Ceramic fuses are used for high-power branches of intelligent electronics and infotainment systems to avoid thermal failure:
 
  1. On-board charging and data transmission: High-power on-board charger (for conventional fuel vehicles with large charging power), car networking T-BOX, 4G/5G communication module main power supply circuit.
  2. Infotainment high-power components: Car audio power amplifier, large-size central control screen backlight drive, head-up display (HUD) power supply circuit, with medium current (10A~25A) ceramic fuses matching the power of audio and display components.
  3. Intelligent driving perception system: Power supply circuits of on-board cameras, millimeter-wave radars and lidar (for L2 and above intelligent driving models), protecting high-precision perception components from overcurrent damage.
 

5. New energy vehicle auxiliary and low-voltage power distribution systems (specialized application scenarios)

 
For pure electric and hybrid vehicles, the high-voltage system is protected by special high-voltage fuses, while ceramic automotive fuses are the core protection components for the low-voltage (12V/24V) auxiliary system (the most important low-voltage protection component for NEVs):
 
  1. Low-voltage power distribution system: NEV low-voltage battery (lead-acid/lithium battery) charging and discharging circuit, DC-DC converter output circuit, which is the core of the low-voltage power supply and adopts high-reliability ceramic fuses.
  2. HVAC and thermal management system: NEV air conditioning compressor (PTC heater for heating), battery cooling fan, water pump power supply circuit, with high power consumption and high working temperature, matching medium and high current ceramic fuses.
  3. Vehicle control and auxiliary system: VCU (Vehicle Control Unit), BMS (Battery Management System) low-voltage power supply circuit, charging port lock, high-voltage interlock circuit, ensuring the normal operation of the NEV core control system.
  4. On-board auxiliary electrical appliances: NEV electric air pump, electric water heater, and other on-board high-power auxiliary electrical appliances power supply circuit, avoiding circuit short circuit caused by harsh working conditions.
 

Key Matching Principles of Ceramic Automotive Fuses in Application

 
  1. Current matching: Select the fuse amperage according to the rated working current of the circuit (usually 1.25~1.5 times the rated current) to avoid false fusing or failure to protect.
  2. Voltage matching: Ensure the fuse's rated voltage is not lower than the circuit's working voltage (12V for passenger cars, 24V for commercial vehicles) to prevent arc reignition after fusing.
  3. Scenario matching: Prioritize ceramic fuses for high-temperature, high-vibration, high-power and safety-related circuits; plastic fuses can be used for low-power, low-temperature indoor circuits to reduce costs.
  4. Type matching: Select the corresponding fuse type (blade type, bolt type, mini type ceramic fuses) according to the automotive fuse box interface and installation space.