Eaton BK/CB123-40B automotive circuit breaker - 4 A, Heavy-Duty Type III
Part Number: BK/CB123-40B
Quick Summary
The Eaton BK/CB123-40B automotive circuit breaker protects vehicle circuits by interrupting overcurrent conditions. For engineers and maintenance teams, unreliable protection or aftermarket fuses can lead to wiring damage, unexpected downtime, and costly warranty claims. RoHS compliant with heavy‑duty Type III construction and a sturdy #10-32 TPI stud design helps deliver durable protection in vibration and temperature extremes. Compact form, easy mounting, and compatibility with lengthwise brackets and covers support faster installs, lower service time, and improved fleet reliability. Together, these attributes translate to measurable business value through safer electrical systems and reduced maintenance costs.
Product Information
Extended Description
BK/CB123-40B Eaton: Eaton Bussmann series C.B.123-B automotive circuit breaker, 4A, Heavy duty, Type III, 10-32 TPI stud
Product Name
Eaton Bussmann series CB123-B automotive circuit breaker
Catalog Number
BK/CB123-40B
UPC
051712601481
Product Length/Depth
0.55 in
Product Height
2.1 in
Product Width
1.7 in
Product Weight
0.44 lb
Compliances
RoHS Compliant Contact factory
Amperage Rating
4 A
Connection
#10-32 TPI stud
Quantity
6
Used with
lengthwise bracket and cover, quick-connect
Bussmann series 4-foot automotive planogram no.10730
BK/CB123-40B~BK-CB123-40B~CIRCUIT BREAKER
BK/CB123-40B~BK-CB123-40B~CIRCUIT BREAKER
Bussmann series Fuseology
Eaton Specification Sheet - BK/CB123-40B
4 A amperage rating provides precise overcurrent protection for sensitive automotive circuits, reducing nuisance trips while protecting wiring harnesses. In practice, this means fewer false positives in diagnostics and safer battery management in passenger and commercial vehicles. Heavy-duty Type III construction enhances durability under continuous vibration and temperature swings found in fleet vehicles and off-road equipment, improving uptime. Connection via #10-32 TPI stud enables solid, high-current connections with common automotive hardware; pairing with the lengthwise bracket and cover simplifies installation and service. RoHS compliance ensures restricted hazardous substances are within spec, helping support automotive supplier certifications and environmental reporting. Compact dimensions (0.55 in length, 2.1 in height, 1.7 in width) and a 0.44 lb weight allow integration into tight enclosures, reducing panel size and thermal concerns. Designed to work with lengthwise brackets and covers and quick-connect accessories, installation is faster, with fewer miswiring incidents and easier field service.
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FAQs
Install the breaker using the #10-32 TPI stud connections and secure it with the provided lengthwise bracket and cover. Pair with quick-connect terminals as needed, ensuring a solid mechanical fit and proper clearance for heat dissipation. Follow standard panel mounting practices to avoid vibration-induced wear.
The BK/CB123-40B carries a 4 A amperage rating, providing precise overcurrent protection for automotive circuits. It protects wiring harnesses and components from damage due to short circuits or overloads, reducing the risk of insulation failure and electrical fires.
Yes, the BK/CB123-40B is RoHS compliant, helping meet regulatory and sustainability requirements for automotive suppliers and fleets. Its heavy-duty Type III design further supports reliability in vibration-heavy fleet and off-road applications.
Yes. The unit is designed to work with lengthwise brackets and covers and supports quick-connect options, enabling faster installation, simplified field service, and reduced risk of wiring mistakes during maintenance.
Key dimensions are 0.55 in length (depth), 2.1 in height, and 1.7 in width, with a weight of 0.44 lb. The #10-32 TPI stud connection and compact footprint help fit into tight automotive enclosures while maintaining robust electrical performance.