Cut Off Switch for Solar Array?

System
System Posts: 2,511 admin
in Solar Beginners Corner #1
Most DC switches are rated at 48 volts max.
I have some 12 volt switches that are rated at 12 volt with a running capacity of 300 amps.
My solar array is going to be in series so my voltage will be around 82 volts open voltage dc at 7 amps max.

Can you run 82 volts dc at 7 amps through a heavy duty 12 volt 300 amp switch with 3\8 inch lugs.

I am looking for a simple cut off switch for my solar panels at the point just before they go into the charge controller.

Thanks in advance.
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Comments

  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
    Re: Cut Off Switch for Solar Array?

    The biggest problem there is with disconnecting panels is doing it while they're putting out power. Covered up or otherwise "in the dark" the current is minimal so any arc that occurs when breaking the connection shouldn't cause any trouble. While connected, the current becomes the issue as you don't want heat building in the contacts. If it can handle the current when closed, the Voltage difference isn't such an issue. That actually comes in to play when trying to break the connection.

    Although there are combiners with fuses and breakers meant to handle just such situations: http://www.solar-electric.com/sopawiinco.html

    I have no disconnect switch on mine; I simply kill the panel output and pull the wire. Turning the array on and off, as it were, is not something that needs to be done frequently.
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  • GreenerPower
    GreenerPower Solar Expert Posts: 264 ✭✭✭✭✭✭
    #3
    Re: Cut Off Switch for Solar Array?
    zero244 wrote: »
    Most DC switches are rated at 48 volts max....I am looking for a simple cut off switch for my solar panels at the point just before they go into the charge controller.
    You can use Outback or Midnight-Solar DC breaker as your DC disconnect. They are rated 150VDC and carry by our host with various amperage - http://www.solar-electric.com/mnepv.html
    GP
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  • SCharles
    SCharles Solar Expert Posts: 123 ✭✭
    #4
    Re: Cut Off Switch for Solar Array?
    GreenerPower wrote: »
    You can use Outback or Midnight-Solar DC breaker as your DC disconnect. They are rated 150VDC and carry by our host with various amperage - http://www.solar-electric.com/mnepv.html
    GP

    This is what I did. The breakers spoken of here cost $13 or so.

    In 25 yr. I've never needed anything else. They are DIN rail breakers and easy to set up, will accept larger ga. wires.
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  • System2
    System2 Posts: 6,290 admin
    #5
    Re: Cut Off Switch for Solar Array?

    Thanks guys for the replies.
    I think I will go with your recommendations and get a simple box and breaker setup.
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  • peakbagger
    peakbagger Solar Expert Posts: 341 ✭✭✭
    #6
    Re: Cut Off Switch for Solar Array?

    Square D sells a traditional looking disconnect for DC applications. It looks like a standard disconnect switch but came with a limited DC rating.
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  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    #7
    Re: Cut Off Switch for Solar Array?

    I have one on my setup
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