splitting DC parallel breakers

garynappi
garynappi Registered Users Posts: 120 ✭✭
in Advanced Solar Electric Technical Forum #1
I have some new 8a Langir parallel breakers and I wonder if cutting the steel parallel trip lever connection will make them separate breakers. 




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  • BB.
    BB. Super Moderators, Administrators Posts: 33,663 admin
    edited March 2024 #2
    Guessing these are the DC Breakers:

    https://www.langir.com/dc-circuit-breaker/

    There are several different wiring configurations, make sure that yours are wired in parallel and not series (series wired for higher interrupt voltage--It appears with a quick read). But, yes, cut the interconnect between breakers to make 2 pole separate breakers... Note that this reduces the breaker's max working Voltage to 250 VDC.

    When cutting the interconnect--Obviously do not allow metal fragments into the breaker.

    Other question, why not just get 2x separate breakers? That would avoid any complications.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • garynappi
    garynappi Registered Users Posts: 120 ✭✭
    edited March 2024 #3
    Thanks and yes, they're DC breakers and voltage will be well below 250 volts but Langir is slick, cutting the steel connection does not work, the two levers will not act independently :-(

    I guess that begs another question, is there any reason I cannot use these 8A parallel breakers for my load? 




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  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,943 ✭✭✭✭✭✭
    #4
    Is it going to be inspected?  If this is just solar input to a CC and you do not stress the breaker you should be fine. The worst that will happen is a failed switch.  If you have 3 + parallel strings that are being protected, you may not be protecting in a failure mode.
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

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  • garynappi
    garynappi Registered Users Posts: 120 ✭✭
    #5
    Thanks, 

    No, the system is not grid tied, not going to be inspected, the power is going to my yard lighting with three strings of LED lights. 








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  • NANOcontrol
    NANOcontrol Registered Users Posts: 279 ✭✭✭
    #6
    Are you looking for a switch or breaker function.  I've tested many of these from China and they will never protect a panel.   Normal interrupt in any reasonable time is over 50% higher.  I had a 32A breaker and it didn't trip at 90A before I had to stop the test because MC4 connector was overheating. 
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  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,943 ✭✭✭✭✭✭
    #7
    One can start a fire with  DC lighting/wiring and even if you do not carry a homeowners policy you can do alot of damage. Pretty cheap to buy the correct low voltage circuit breaker or fuse.
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

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  • RCinFLA
    RCinFLA Solar Expert Posts: 1,485 ✭✭✭✭
    #8
    Dual pole breakers are required for PV panels on transformerless GT inverters and most HF grid-interactive all-in-one hybrid inverters because AC mains are not isolated from PV.  Positive and negative lines from PV array must be opened to ensure no AC voltage remains on panel.  
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