This 20A shortstop automatic reset circuit breaker is designed with an IP66 rated protective plastic housing for superior vibration resistance within automotive, agricultural and marine vehicles. This circuit breaker is ideal for use in a variety of low voltage applications including some car stereos, power windows, door locks, sunroofs, headlights, etc. Each breaker has been thoroughly tested to meet SAE J553 & J1171 standards and features two 10-32 stud terminals for easy wire attachment. Circuit breakers are also available in Non-Cycling (Type II) and Manual Reset(Type III). 


  • Standard 20A shortstop automatic/ cycling reset circuit breaker
  • Designed with an IP66 rated protective plastic housing
  • Superior vibration resistance
  • Features a right angle/ perpendicular bracket for easy mounting
  • Features (2) 10-32 stud terminals for easy wire attachment
  • Meets SAE standards J553 & J1171
  • Metal Plated housing shortstop circuit breakers are also available

Technical Specifications 

  • Manufacturer: Cooper Bussmann
  • Manufacturer Part Number: 121B20-A2P-KA
  • Amps: 20
  • Type: Shortstop
  • Reset Method: Type I (Automatic)
  • Mounting Style: Right Angle Bracket
  • Housing Material: Plastic
  • Terminal Connection: 10-32 Studs
  • SAE Compliance: J553; J1171