Bussmann CB123-15HB Eaton series CB123-HB automotive circuit breaker, 24 Vdc, 15A, 1.5 kAIC at 12 Vdc, Automotive, type III, heavy duty, #10-32 TPI stud

The CB123-15HB is rated 24 V DC, so it works on both 12-volt and 24-volt vehicle and equipment systems. Its interrupting rating is published at 1.5 kAIC at 12 Vdc, which is the fault current it can safely break on a standard automotive battery system.

Terminals are #10-32 TPI studs, so you need ring terminals sized for a #10 screw, secured with the stud nuts. Push-on blade or spade terminals will not land on it. Size the ring lugs to the wire gauge protected by the 15 A rating.

This is a Type III breaker, which in automotive breaker terms is the manual-reset style: it stays tripped until someone presses the reset, unlike a Type I auto-reset that cycles on its own. Use it where you want a fault to stay off until it has been looked at, which is why it is a common pick for fleet and equipment work instead of an auto-resetting unit.

It is a 15 amp breaker. That suits accessory and auxiliary circuits like lighting, wipers, radios, small pumps and aftermarket add-ons where the conductor is sized for 15 A. For higher draw loads such as winches or inverters you need a higher amp breaker in the same CB123-HB family rather than doubling up on this one.

Yes, and that is the usual reason to fit one. It protects the same 15 A circuit but resets instead of being consumed, so a nuisance trip does not cost you a fuse or a trip to the parts store. The trade-off is the mounting: a blade fuse drops into a fuse block, while this breaker needs two #10-32 stud connections with ring terminals and room for its 0.55 x 1.7 x 2.1 inch body.

Order by Bussmann part number CB123-15HB, from the Eaton CB123-HB heavy duty series. The suffix carries the amp rating, so CB123-15HB is the 15 amp version of that series.