Circuit Breaker/Shutoff comparison

I am currently planning another installation for the mission I work with in the Dominican Republic. (
Trying to keep costs as low as possible without sacrificing quality.

I have discovered that Bussman makes two kinds of circuit breaker/shutoff devices. One is the CB185, the other is the MRCB. The only difference I see in them is that fact that the MRCB is ignition protected? I have the MRCB's on the current installation. Has anyone used the CB185 model?

I use these between the batteries and the charge controller and the batteries and the inverter, the systems are 12 volt.

The cost difference is significant.

Thanks for your input,


Attachment not found.
Two systems in the Dominican Republic
installed Feb 2014 at 19.796189° -70.893594°, Classic 150 + WBJR, KISAE SW1210, MN Battery Monitor, IOTA DLS 55/IQ4,  4- Solar World 275w, 4-6v x 225ah Trace Batteries
installed Feb 2015 at 19.795733° -70.893372°, same components  as above
Honda PowerMate PC0497000, 7000/8750w generator - powers the well and chargers maybe once a week


  • BB.BB. Super Moderators, Administrators Posts: 31,615 admin
    Re: Circuit Breaker/Shutoff comparison

    Here is a detailed data sheet for the MRCB: (185 series) (187 series) (IP66 vs IP67 rating)

    The two are very similar and carry about the same Marine ratings... The MRCB has 5/16" studs and the 185 has 1/4". The MRCB (187) is available in 200 amp rating max, the 185 only 150 Amp max. The 185 with IP67 can be submerged in 15cm to 1 meter of water.

    Otherwise, excluding price, I don't see any reason to pick one over the other for solar application. The data sheets have different specification bullet points (one lists number of manual cycles rating, the other does not, etc.).

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • westbranchwestbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Re: Circuit Breaker/Shutoff comparison

    Your picture told me the difference right away... one is water PROOF the other RESISTANT.. If you are not on a boat, and do not need power when the CB is under water (??? don't know when you would need that function anyway??) the resistant would work just fine for your land based application.
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • mike95490mike95490 Solar Expert Posts: 9,261 ✭✭✭✭✭
    Re: Circuit Breaker/Shutoff comparison

    Midnight also carry's some breakers (many) and some are rated for switching duty, some DC breakers are not rated for frequent use as a switch.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    gen: ,

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