Question about an AC Lightning Arrestor install

dancour
dancour Registered Users Posts: 9 ✭
in PV Installers Forum - NEC, Wiring, Installation #1
I want to install an AC (LA 302R) lightning arrestor on the AC side of my (SunnyBoy) inverter. Where is the best place to wire it in? Does it need its own 2 pole beaker?

Thanks
PS I already have a DC LA on the DC line from the panels.
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Comments

  • dsp3930
    dsp3930 Solar Expert Posts: 66 ✭✭✭✭
    #2
    Re: Question about an AC Lightning Arrestor install

    They should be connected to Hot 1/Hot 2/Neutral/Ground. You don't hook them up to a breaker.
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #3
    Re: Question about an AC Lightning Arrestor install

    as to placement, it should be as close as you can reasonably get it to the inverter to minimize further emp pickup to the short interim wire connection. do not run the input and output wires of the arrestor side by side either as this would act like a transformer and effectively bypass the arrestor.
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  • solarix
    solarix Solar Expert Posts: 713 ✭✭
    #4
    Re: Question about an AC Lightning Arrestor install

    I've got a local permit plan checker that wants to know if Delta surge arrestors are listed for mounting in accessible locations (in a knockout on a service entry) as per NEC 280. Anybody know about this? Are these arrestors listed for this - or - is this not accessible because the wiring end is inside the service entry?
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #5
    Re: Question about an AC Lightning Arrestor install

    they are made to mount inside of them and the link shows their certifications.
    http://www.deltala.com/prod02.htm
    not sure what those certifications mean though, but one of them is bound to tell the inspector if it is. if you or the inspector still don't have the answer from the link them write to delta.
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  • GreenerPower
    GreenerPower Solar Expert Posts: 264 ✭✭✭✭✭✭
    #6
    Re: Question about an AC Lightning Arrestor install

    Installation instructions from Delta. Put it as close to the device you want to protect as possible. I would put one in the main breaker box (general protection), one in the sub-breaker box (sub load protection) and use 3000-joule MOVs on each phase & neutral wires at the inverter to ground. Any long wires between breaker boxes or breaker box to device could pickup surge (also wires from PVs to CC).
    The Outback inverter guarantee is not honored if their own approved MOVs are not installed at the inverter.
    GP
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  • solarix
    solarix Solar Expert Posts: 713 ✭✭
    #7
    Re: Question about an AC Lightning Arrestor install

    It appears that Delta arresters are not listed for accessible locations per the code. Their instructions show that they can be mounted through service entry knockouts, but they say to install them internally. Our decision as a result is to discontinue installing them at all because they will not fit inside an inverter's disconnect.
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