Announcement

Collapse
No announcement yet.

Electrical shock with wet panels

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Electrical shock with wet panels

    Hi all,

    I am an integrator of Solar panels.

    I had problems in 2 of my installations with getting shocked when touching the PV module glass when this one is wet and I am touching another surface.

    I would like to know if any one else had a similar problem and if this is normal.

    I would like to add that modules are grounded in the frame and in the negative pole,

  • #2
    Originally posted by marcland View Post
    I would like to add that modules are grounded in the frame and in the negative pole,
    That is why you got shocked.
    MSEE, PE

    Comment


    • #3
      Originally posted by marcland View Post

      I would like to add that modules are grounded in the frame and in the negative pole,
      Can you upload a line drawing that shows your grounding scheme? What kind of inverter is being used? At what point in the installation are you getting shocked? Ungrounded systems would be safer, but only newer inverters are designed to operate that way.
      CS6P-260P/SE3000 - http://tiny.cc/ed5ozx

      Comment


      • #4
        Hi,

        This happened in a system with SMA back up with SB and SI.

        The SB is 4000TL. Modules are grounded with normal grounding from the structure.
        Electrical wiring is protected with DC surges arresters.

        That happens only on when touching the glass not frame or other parts. It is like the electricity jumping through the glass. Electricity comes even through the water up to the hand.

        Comment


        • #5
          Originally posted by marcland View Post
          Electrical wiring is protected with DC surges arresters.
          It is not possible for surge arrestors to protect any wiring.
          MSEE, PE

          Comment


          • #6
            Originally posted by marcland View Post
            The SB is 4000TL. Modules are grounded with normal grounding from the structure.
            Why would you ground the DC- of this inverter? From the manual:

            6.4.2 Conditions for the DC Connection
            The inverter is transformerless
            and has no galvanic isolation.
            Therefore, the inverter may only be
            operated with ungrounded PV arrays.
            CS6P-260P/SE3000 - http://tiny.cc/ed5ozx

            Comment


            • #7
              Wet glass can have electrical leakage along the conductive water path, dry glass is an insulator. But the bigger question is how it's happening. The DC connectors should be sealed, and not allow any leakage. This then indicates maybe the glass/frame seal is bad, and the moisture conducting from there. That would be VERY bad, and cause early panel failure.

              Another test, is to get a Neon light based tester, and see if the current is DC (one side of the bulb lights) or AC (both elements light) There is a chance that Induced AC is appearing on the panels - are there high voltage powerlines in the neighborhood ? I could on dry days, get a tingle from my car, when working on it, induced from the power lines across the street:ViewInstall_c.jpg
              Powerfab top of pole PV mount (2) | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
              || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
              || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

              solar: http://tinyurl.com/LMR-Solar
              gen: http://tinyurl.com/LMR-Lister

              Comment


              • #8
                If there is a conductive path from DC to ground, whether it was put there intentionally or it occurs by a bad glass seal and water providing continuity to the frame, shouldn't that trigger the inverter's GFDI?
                CS6P-260P/SE3000 - http://tiny.cc/ed5ozx

                Comment


                • #9
                  Originally posted by sensij View Post
                  If there is a conductive path from DC to ground, whether it was put there intentionally or it occurs by a bad glass seal and water providing continuity to the frame, shouldn't that trigger the inverter's GFDI?
                  Yes if it is wired correctly to code. That is what it is there for.
                  MSEE, PE

                  Comment


                  • #10
                    Originally posted by sensij
                    If there is a conductive path from DC to ground, whether it was put there intentionally or it occurs by a bad glass seal and water providing continuity to the frame, shouldn't that trigger the inverter's GFDI?
                    The "GFI" detector in my inverters requires over 1A of leakage current for any response.
                    That is way beyond a safe level for personal. GFIs for people trigger at 0.005 A or less.

                    If you are getting a tickle from panels, there may indeed be faulty insulation there. But
                    as for my own hide, I always assume there is a fault and keep myself isolated from any
                    active elements of the system. Bruce Roe

                    Comment


                    • #11
                      Originally posted by bcroe View Post
                      The "GFI" detector in my inverters requires over 1A of leakage current for any response.
                      That is way beyond a safe level for personal. GFIs for people trigger at 0.005 A or less.

                      If you are getting a tickle from panels, there may indeed be faulty insulation there. But
                      as for my own hide, I always assume there is a fault and keep myself isolated from any
                      active elements of the system. Bruce Roe
                      Yeah, your Fronius's design doesn't give the same level of ground fault detection that the transformerless SMA's can achieve. A 30 mA change in current, or 100 mA absolute current, is enough to trigger it. Here is one of the presentations that discusses it from when the product was being launched.
                      CS6P-260P/SE3000 - http://tiny.cc/ed5ozx

                      Comment


                      • #12
                        Originally posted by sensij View Post
                        Yeah, your Fronius's design doesn't give the same level of ground fault detection that the transformerless SMA's can achieve. A 30 mA change in current, or 100 mA absolute current, is enough to trigger it. Here is one of the presentations that discusses it from when the product was being launched.
                        The Fronius perform well, but their Ground Fault technology is crude. I see it as quite
                        adequate for equipment faults, but not for people. That isn't an unusual situation in
                        powerful systems.

                        Detecting .030A DC before startup isn't so difficult. Detecting DC leakage in operation
                        is much more difficult, unlike the .005A AC detectors for people. I really wonder what
                        is the practical limit given that a huge array of outdoor equipment is going to have
                        leakage at some level?

                        Now I will need to set up an experiment to see just what my systems leakage is. I will
                        ground one terminal through a shunt (1K ohm resistor) and measure the shunt voltage,
                        then try it again grounding the other terminal instead. Will do East and West systems.

                        Bruce Roe

                        Comment


                        • #13
                          SolarEdge uses a detection technique similar to SMA, and also chose a 30 mA delta current as the trip threshold. This is a value in operation, not a start-up check. They report that changes as low as 15 mA may trip in some systems. Their default absolute level is 300 mA, but it can be set as low as 100 mA.
                          CS6P-260P/SE3000 - http://tiny.cc/ed5ozx

                          Comment


                          • #14
                            Originally posted by sensij View Post
                            SolarEdge uses a detection technique similar to SMA, and also chose a 30 mA delta current as the trip threshold. This is a value in operation, not a start-up check. They report that changes as low as 15 mA may trip in some systems. Their default absolute level is 300 mA, but it can be set as low as 100 mA.
                            100 ma is considered lethal.
                            MSEE, PE

                            Comment


                            • #15
                              Originally posted by Sunking View Post
                              100 ma is considered lethal.
                              The amount of time exposed matters. The 30 mA delta trip level is what is designed for human safety. If your point is that the 1 A fuses on the Fronius and other grounded transformer based inverters will not prevent lethal fault current, I fully agree!
                              CS6P-260P/SE3000 - http://tiny.cc/ed5ozx

                              Comment

                              Working...
                              X