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  • Solar panel grounding

    I rejuvenate an old thread, but it never showed up in the new posts list. So I start over. It's probably redundant, but I didn't find anything else close to my question.

    I've become a pro with small wind generators, but am total nit wit with Solar. I've just ordered my first round of panels.

    Here is the question.

    What is the proper way of grounding panels?

    I am planning on bolting the panels down, using dielectric grease to some solid rails. Then I was thinking of just attaching a ground loop to each rail. Then it's to my negitive side of my buss, and earth grounds. Does this sound like a good plan? Simple and clean. Not interested in all that fancy railing. I'm already on a 45* pitch.

    Thanks in advance

  • #2

    Re: Solar panel grounding

    Re: Solar panel grounding

    Building Code, I believe, does not permit your version. Instead, there is supposed to be a long, continuous ground conductor, fastened to each panel, with a code approved device, at, and only at, the panel mfg's designated grounding point.
    http://tinyurl.com/LMR-Solar
    http://tinyurl.com/LMR-BigLug
    http://tinyurl.com/LMR-NiFe

    Grundfos 10 SO5-9 with 3 wire Franklin motor (1/2hp 240V 1ph # 214505 ) on a timer for 3 hr noontime run - Runs off PV
    Powerfab poletop PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe battery | 15, Evergreen 205w "12V" PV | Midnight ePanel || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT

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    • #3

      Re: Solar panel grounding

      Re: Solar panel grounding

      i believe they may be requiring the rails to be grounded as well, but don't quote me. i don't agree with this as the pvs will act much like a faraday shield for the rails, plus the rails are usually connected to the pvs well enough that should it (lightning, emp, or whatever) enter a rail it would transfer to the pv as the least path of resistance to ground.
      NIEL

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      • #4

        Re: Solar panel grounding

        Re: Solar panel grounding

        I like the Tyco Solklamp product. Not cheap, but none of the approved lay-in lug devices are. Wiley ground washers are cheap but most AHJ's don't go for them.
        Why don't the module makers build in a device? I would love it if there was a built in lug inside the frame (so it doesn't stick out and get in the way).
        Putting the lugs on is always a hassle and can't be prepped ahead because you can't stack the modules once the ground lug is sticking out and also can tear into the roofing etc. I'm sure it would be a lot cheaper for the manufacturers to build it in (weld in on) and they could ensure how it is used that way. Plus the current devices do a poor job of biting through the aluminum surface to make a good gas-tight electrical connection imho.
        2.7kW Trina/Xantrex GT, 3.7kW Trina/SolarEdge, 3kW CSI/SMA GT, Solar well pump on 6, 25yr old Holeck 48W modules. Toyota SR5 converted to 108V EV. Prius w/Enginer PHEV conversion. BSEE, R11-residential, NABCEP, SunnyPro, >800kW installed
        "Faced with the choice between changing one's mind and proving that there is no need to do so, almost everyone gets busy on the proof." - John Kenneth Galbraith

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        • #5

          Re: Solar panel grounding

          Re: Solar panel grounding

          Originally posted by niel View Post
          i believe they may be requiring the rails to be grounded as well, but don't quote me. i don't agree with this as the pvs will act much like a faraday shield for the rails, plus the rails are usually connected to the pvs well enough that should it (lightning, emp, or whatever) enter a rail it would transfer to the pv as the least path of resistance to ground.
          I'm not familiar with the acumen's Niel. Forgive a rusty old man and define please? I'm a rookie on the solar side

          Thanks Guys. It's what I thought. There is no real standard. Some greedy went to the NEC and got their crap approved, raising the install costs bu tripple. There are allot easier and less expensive ways. And they wonder why more people aren't doing it.

          So far, my plan seems to be working the best

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          • #6

            Re: Solar panel grounding

            Re: Solar panel grounding

            Only the frames & mounting parts of the panels should be grounded where the panels are mounted, for lightning protection. The negative side should NOT be grounded where the panels are mounted. The negative is usually the grounded side, but it should be grounded where it terminates - usually at the inverter for grid tie systems. (Some microinverters use a positive ground, but that does not affect the panel grounding).
            Northern Arizona Wind & Sun Forum & Website Administrator

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            • #7

              Re: Solar panel grounding

              Re: Solar panel grounding

              windsun translated that as it was the mounts that i was referring to.
              NIEL

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              • #8

                Re: Solar panel grounding

                Re: Solar panel grounding

                Originally posted by Windsun View Post
                Only the frames & mounting parts of the panels should be grounded where the panels are mounted, for lightning protection. The negative side should NOT be grounded where the panels are mounted. The negative is usually the grounded side, but it should be grounded where it terminates - usually at the inverter for grid tie systems. (Some microinverters use a positive ground, but that does not affect the panel grounding).
                Now that's a new problem for me. I have wind also which has to be earth grounded as there is no other way. Unless you think the frames and grounding the inverters is suffucient

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                • #9

                  Re: Solar panel grounding

                  Re: Solar panel grounding

                  The issue is not if it is earth grounded, but where. One of the biggest problems with a DC electrical ground at the panels is that you can get some really severe corrosion on any metal that touches the ground, due to it acting as one of the electrodes in the circuit. The problem is that you can end up with two different paths for the DC current - one of those through the ground, and since any metal touching the ground will act as either a cathode or anode, something will get corroded by stray DC currents. That is one of the main reasons for having a single point ground.
                  Northern Arizona Wind & Sun Forum & Website Administrator

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                  • #10

                    Re: Solar panel grounding

                    Re: Solar panel grounding

                    not all the solar panel need grounding, that dicide by the system inspection unit. somewhere will ask your system grounding.but in some special panel, just like thin-film with frame, they will ask the panel grounding for extend the life of the panel.

                    skype ID:kevin_wang59

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                    • #11

                      Re: Solar panel grounding

                      Re: Solar panel grounding

                      Originally posted by kevin View Post
                      not all the solar panel need grounding, that dicide by the system inspection unit. somewhere will ask your system grounding.but in some special panel, just like thin-film with frame, they will ask the panel grounding for extend the life of the panel.

                      skype ID:kevin_wang59
                      kevin,
                      i think you lost me on this. what are you saying here? is it not all of the pvs need grounded or that only a part of a pv needs grounded? the 1st part is not true and the 2nd is impossible.

                      i also have no idea what you are talking about as far as a thin film pv example as grounding does not extend the life of the pv unless it averted a lightning strike or an emp event. the only other incident grounding plays a part in pv life is the positive grounding sun power pvs require.
                      NIEL

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                      • #12

                        Re: Solar panel grounding

                        Re: Solar panel grounding

                        Originally posted by Windsun View Post
                        The issue is not if it is earth grounded, but where. One of the biggest problems with a DC electrical ground at the panels is that you can get some really severe corrosion on any metal that touches the ground, due to it acting as one of the electrodes in the circuit. The problem is that you can end up with two different paths for the DC current - one of those through the ground, and since any metal touching the ground will act as either a cathode or anode, something will get corroded by stray DC currents. That is one of the main reasons for having a single point ground.
                        You say single point ground. You mean just the mounting and the frames be grounded? Not the negitive side on the panels. I guess I can't protect my towers then.

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                        • #13

                          Re: Solar panel grounding

                          Re: Solar panel grounding

                          Read about Cathodic protection.

                          And Cathodic Protection 101

                          -Bill
                          20x BP 4175B panels (replacement) + Xantrex GT 3.3 inverter for 3kW Grid Tied system + Honda eu2000i Inverter/Generator for emergency backup.

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                          • #14

                            Re: Solar panel grounding

                            Re: Solar panel grounding

                            Familiar with the zinc anoid process, but that doesn't answer my question

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                            • #15

                              Re: Solar panel grounding

                              Re: Solar panel grounding

                              Not sure what your question is... For Grid Tied systems, the Negative (or Positive for Sun Power panels) PV electrical bus is grounded to earth through a 1 amp fuse (typically). Not sure what is connected/grounded for tranformerless/non-isolated GT inverters that are just coming out now in the US (Europe has used these a bit longer).

                              For a battery based system, typically we recommend grounding a permanent install to the negative battery bus--which is almost always carried through the charge controller (the PV- and Batt- are tied together inside most charge controllers).

                              -Bill
                              20x BP 4175B panels (replacement) + Xantrex GT 3.3 inverter for 3kW Grid Tied system + Honda eu2000i Inverter/Generator for emergency backup.

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