metal roof mounting with s-5 pv kit?

Peak Solar
Peak Solar Registered Users Posts: 13 ✭
in PV Installers Forum - NEC, Wiring, Installation #1
Does anyone here have any experience mounting pv on a standing seam metal roof using the s-5 pv kit or similar without using rails?

I am looking for advice on grounding this type of mounting system.

Thanks.
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  • wdegrace
    wdegrace Registered Users Posts: 8 ✭
    #2
    Re: metal roof mounting with s-5 pv kit?

    I have installed systems using the S-5 clips in both residential and commercial applications. I assume you are referring to the system ground. You will have to ground each panel in the system with a bare copper grounding wire. If you mount to rails instead, you can run the grounding wire through the appropriate grounding lug on each rail.

    Now, keep in mind that if you go to purchase S-5's you will need the base and the PV connection. I usually use the S-5 U or (utility) with the PV end and midclamps for the unirac system.

    In addition, if you plan on installing a large amount of panels it can be quite difficult keeping the array square.
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  • Peak Solar
    Peak Solar Registered Users Posts: 13 ✭
    #3
    Re: metal roof mounting with s-5 pv kit?

    Thanks for the reply. s-5 has told us that we will need the s-5-U mini for the clamp and we are using the pv kit to mount the modules flat on the roof, directly to the clamps without rails.

    Since there are no rails to ground to, does each individual clamp need to be grounded or just the modules?
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  • anthem
    anthem Registered Users Posts: 8 ✭
    #4
    Re: metal roof mounting with s-5 pv kit?

    Hey Peak Solar - I am looking at doing the same. I have done quite a bit of research as well on this, so here are my notes:

    -If you use S5's PV kit, they only match up with S5's mini-clamp (single screw) not the regular s5 clamp.

    -If you plan on say using unirac rails - then its paired with the S5 clamp and NOT the s5-mini. Also unirac has their own clamp now, so not sure how hard they are pushing the s5/solarframe combination from s5 anymore.

    Our concern with just mounting directly to the s5-mini is that it might just be too close. The panels will probably be around 3" off the standing seam, with maybe 2" of clearance from the panel to the bottom edge of the modules. What happens during the fall if their are leaves flying around ? Will it get trapped underneath ???? There is also the expected loss of another 5% in efficiency due to higher heat from it being mounted so close.

    Also, a consideration is if you plan on using microinverers. You'll have to have two extra clamps to tie each microinverter to a seam underneath the panel. We haven't confirmed whether this will fit underneath the panel yet as I believe this will be very close as well.

    Anyhow, the look is excellent with how close it is. We may have to only consider this for steeper roofs due to debris issues. So perhaps fine on 6/12 standing seam, but maybe stay with s5/rails for 4/12 and below ???
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  • System2
    System2 Posts: 6,290 admin
    #5
    Re: metal roof mounting with s-5 pv kit?
    wdegrace wrote: »
    I have installed systems using the S-5 clips in both residential and commercial applications. I assume you are referring to the system ground. You will have to ground each panel in the system with a bare copper grounding wire. If you mount to rails instead, you can run the grounding wire through the appropriate grounding lug on each rail.

    Now, keep in mind that if you go to purchase S-5's you will need the base and the PV connection. I usually use the S-5 U or (utility) with the PV end and midclamps for the unirac system.

    In addition, if you plan on installing a large amount of panels it can be quite difficult keeping the array square.
    ^ About the bare copper. Keep in mind your corrosion tables. Depending on the finish of roof this might not be the safest product to use. Unless the roof is painted or some type of coating you should use tin coated copper wire.

    I have also used S5! on residential and commercial jobs and it is a great install once you get the hang of it. Make sure you set your first line perfect, any step now will just multiply every module that follows.
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #6
    Re: metal roof mounting with s-5 pv kit?

    i agree with mylch that the roof in contact accidentally or on purpose with the wire will cause galvanic reactions and eat away at the metals of both. a leaking roof and a compromised ground wire is not a good result. if you have an inspector then consult with his recommendations, but odds are they would allow the wire to be used with a green jacketed wire of the appropriate voltage rating approved for outdoor weather and sun.
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