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    #31
    Originally posted by five.five-six View Post
    So, I have a buddy in my aquarium club who has been with the local natural gas company for many years. He told that the gas meter needs to be at least 3 linear feet from any electrical equipment such as an inverter and that they may require you to relocate one or the other if the meter is too close the inverter. He also told me that the rule has been relaxed to only require a 3’ circle around the meter. Has anyone else ran into this?
    In the AHJ's we service there is some variability; some say 3' measured radially and some say 3' measured linearly along the wall at any height. What they agree upon is the point from which the measurement is taken; it's the vent on the pressure relief valve adjacent to the gas meter itself.

    Comment


      #32
      Originally posted by five.five-six View Post

      Also, my 9-year-old made this inverter “unboxing” video on youtube. Do me a favor and watch it in a separate browser so he gets “views” on it. It means the world to him at this age and he is really excited about the 77 views it already has. Like and or comment for bonus points. Thanks

      https://youtu.be/i8tscM2yuEA
      Great video, "Who needs instructions?" He will go far.

      I have to wonder how you can wear that shirt around your son though.

      Comment


        #33
        Originally posted by pv_n00b View Post
        Great video, "Who needs instructions?" He will go far.

        I have to wonder how you can wear that shirt around your son though.
        LMAO

        I’m raising them to have thick skin.

        I don’t think he has any idea what that shirt is about. I got it long before either of them were born. I can’t really wear it in public so it’s been a good “working around the house” shirt

        Comment


          #34
          A couple of things to keep in mind

          Your son did a great job on the video. Hope he follows up with a completed project video, maybe interviewing installer/contractor?

          A few things to keep in mind for this and future installs. ( 2017 NEC).

          1. THHN cannot be used in exterior raceways (EMT) on the roof. 300.38, 310.10(C)

          2. Be sure to double check your local ambient temperature and the spacing height above the roof to the bottom of the conduit you will be installing.

          Chances are # 10 will not be enough ampacity, especially if you are combining strings. Table 310.15(B)(16) is only accurate for ambient temperature of 86 degrees F (see paragraph at the top of the table). You have to adjust the ampacity based upon table 310.15(B)(2)(a) for your local area.

          If you do not know your local ambient temperature, a guide is available for free PDF from Copper Development Association. https://www.copper.org/applications/...df/rooftop.pdf

          If the bottom of the conduit is less than 7/8" off the roof, you also have to add 60 degrees F to the ambient temperature for your local area. 310.15(B)(3)(c).

          And if you have more than 3 current carrying conductorsin the conduit, you have to reduce the ampacity even further per Table 310.15(B)(3)(a).

          It is very common in my area for a #10 to only carry 16 amps on a roof.
          " One of my reasons for success: I learned to feel comfortable being uncomfortable." -- Cal Ripken, Jr.

          Comment


            #35
            Originally posted by inspector23 View Post
            ...

            A few things to keep in mind for this and future installs. ( 2017 NEC).

            1. THHN cannot be used in exterior raceways (EMT) on the roof. 300.38, 310.10(C)
            Hard to find THHN these days that isn't also marked THWN. I did have an issue a few years ago where my supplier slipped me some wire that wasn't marked THWN-2.


            2. Be sure to double check your local ambient temperature and the spacing height above the roof to the bottom of the conduit you will be installing.

            Chances are # 10 will not be enough ampacity, especially if you are combining strings. Table 310.15(B)(16) is only accurate for ambient temperature of 86 degrees F (see paragraph at the top of the table). You have to adjust the ampacity based upon table 310.15(B)(2)(a) for your local area.

            If you do not know your local ambient temperature, a guide is available for free PDF from Copper Development Association. https://www.copper.org/applications/...df/rooftop.pdf

            If the bottom of the conduit is less than 7/8" off the roof, you also have to add 60 degrees F to the ambient temperature for your local area. 310.15(B)(3)(c).

            And if you have more than 3 current carrying conductorsin the conduit, you have to reduce the ampacity even further per Table 310.15(B)(3)(a).

            It is very common in my area for a #10 to only carry 16 amps on a roof.
            #10 is usually fine for up to three Solaredge strings unless the design temperature used is very high. I suppose where I am in northern California this may be more true than in the southern parts. In any case, these strings are typically not combined on the roof and only have a circuit current of 15A.

            The 7/8" remark is not correct under the 2014 NEC. The adder is 40F for .5" to 3.5." We've got 5 months to go now until the code changes in California.

            Comment


              #36
              Originally posted by inspector23 View Post
              Your son did a great job on the video. Hope he follows up with a completed project video, maybe interviewing installer/contractor?

              A few things to keep in mind for this and future installs. ( 2017 NEC).

              1. THHN cannot be used in exterior raceways (EMT) on the roof. 300.38, 310.10(C)

              2. Be sure to double check your local ambient temperature and the spacing height above the roof to the bottom of the conduit you will be installing.

              Chances are # 10 will not be enough ampacity, especially if you are combining strings. Table 310.15(B)(16) is only accurate for ambient temperature of 86 degrees F (see paragraph at the top of the table). You have to adjust the ampacity based upon table 310.15(B)(2)(a) for your local area.

              If you do not know your local ambient temperature, a guide is available for free PDF from Copper Development Association. https://www.copper.org/applications/...df/rooftop.pdf

              If the bottom of the conduit is less than 7/8" off the roof, you also have to add 60 degrees F to the ambient temperature for your local area. 310.15(B)(3)(c).

              And if you have more than 3 current carrying conductorsin the conduit, you have to reduce the ampacity even further per Table 310.15(B)(3)(a).

              It is very common in my area for a #10 to only carry 16 amps on a roof.

              I’m running 2 sets of #10’s back to the inverter and a #8 EGC bond.

              My understanding is the #8 needs to be contagious to the Jbox on the roof where I land it on a ground buss and then bond the rails to that buss

              Just to be clear, #10 THHN/THWN will be ok from the j-box to the inverter even if some of it is in EMT on the roof?

              My tubeing is 4” off the roof and my area would be Ontario california.

              Comment


                #37
                Wiring in EMT is fine as long as it is wet rated, i.e. of a type with a 'W' in it.

                To use #10 on the roof for Solaredge strings it will need to be 90C wire, i.e. with '-2' at the end.

                Thus THWN-2. Most suppliers will give that to you by default but double check.

                Now for the size...

                Your SolarEdge string is max 15A which is 18.75 at 125% continuous.
                90C wire is rated 40A which with 4-6 conductors is 32A at 80%.
                18.75/32 is .58 so that's the minimum temperature derating factor you can use. Works for me almost all the time but Ontario may get hotter than where we work. Depends on your AHJs feelings about the ambient temp you use.

                Comment


                  #38
                  Originally posted by jaggedben View Post
                  Wiring in EMT is fine as long as it is wet rated, i.e. of a type with a 'W' in it.

                  To use #10 on the roof for Solaredge strings it will need to be 90C wire, i.e. with '-2' at the end.

                  Thus THWN-2. Most suppliers will give that to you by default but double check.

                  Now for the size...

                  Your SolarEdge string is max 15A which is 18.75 at 125% continuous.
                  90C wire is rated 40A which with 4-6 conductors is 32A at 80%.
                  18.75/32 is .58 so that's the minimum temperature derating factor you can use. Works for me almost all the time but Ontario may get hotter than where we work. Depends on your AHJs feelings about the ambient temp you use.
                  Oddly enough about 1/2 of my #10 isn’t THWN-2. I do have several red and several black but I was hoping to make each string a different color. Not a huge problem though.

                  This is a problem. I did take all the SolarEdge online courses and read everything I could find but I don’t recall anything saying to take down the optimizers serial numbers.... until I unboxed the inverter.... which was after I installed the modules. Is there a good way to identify the optimizers without removing the modules now?


                  And here’s our latest “unboxing” video. Thanks for all the views, comments and likes. They made my son’s day


                  https://youtu.be/lxV4DzAOvoM

                  Comment


                    #39
                    Depending on the rail you used, it may be possible to stick a cell phone under the array and get pics of some of the optimizer serial numbers on the bottom of the mounting bracket. That is for optimizers mounted near enough to the edge of the array.

                    Otherwise, you can just fake your way through the array map and as long as you are the one doing any servicing it won't really matter. Later on if/when you have to pull up panels to find a bad optimizer you can take that opportunity to correct relevant portions of the map.

                    Don't ask me how I know these things.

                    Comment


                      #40
                      Originally posted by jaggedben View Post
                      Depending on the rail you used, it may be possible to stick a cell phone under the array and get pics of some of the optimizer serial numbers on the bottom of the mounting bracket. That is for optimizers mounted near enough to the edge of the array.

                      Otherwise, you can just fake your way through the array map and as long as you are the one doing any servicing it won't really matter. Later on if/when you have to pull up panels to find a bad optimizer you can take that opportunity to correct relevant portions of the map.

                      Don't ask me how I know these things.

                      I was thinking I could just set a tarp over each mod one at a time to identify which is which...


                      I think the way I installed them, the serial number is right against the rail

                      I’ll have to check next time I’m up there but I think if the ser is exposed, I could get them all with a “selfie stick” LOL

                      Comment


                        #41
                        Good ideas. You'll need to wait at least 5 minutes, probably 10-15, between each panel to use the monitoring to determine the locations. Use a piece of cardboard that covers each long row of cells, that's all you need.

                        Comment


                          #42
                          Originally posted by jaggedben View Post
                          Good ideas. You'll need to wait at least 5 minutes, probably 10-15, between each panel to use the monitoring to determine the locations. Use a piece of cardboard that covers each long row of cells, that's all you need.

                          Let me ask you this,

                          If I only connect one string at first, could I then make a list of ser numbers on that string and then I could 2 modules at a time, one on each string?

                          Comment


                            #43
                            Originally posted by five.five-six View Post
                            Let me ask you this,

                            If I only connect one string at first, could I then make a list of ser numbers on that string and then I could 2 modules at a time, one on each string?
                            Connecting one string first would certainly help you narrow things down, as long as you remember how you arranged the string wiring on the arrays. I don't understand the second idea you have.

                            Comment


                              #44
                              If you can easily cover an arbitrary subset of your panels, you can determine the serial numbers for n panels in ceiling(log2n) measurements, rather than n measurements.

                              For example, with 8 panels (labelled 0 through 7), just 3 measurements:

                              A) Cover panels 0, 1, 2 ,3
                              B) Cover panels 0, 1, 4, 5
                              C) Cover panels 0, 2, 4, 6

                              Then each panel's pattern of coverage/noncoverage for the 3 measurements is unique, so you can assign the serial number with the same pattern of coverage/noncoverage to that panel.

                              Of course, covering an arbitrary subset of your panels may be difficult, so it may be easier to cover fewer panels each time and do more measurements.

                              Cheers, Wayne

                              Comment


                                #45
                                Sheesh Wayne, if I were doing this I would have to consider whether it would take me more time to work through the logic than to just cover one panel at a time.

                                In seriousness, I suppose it would depend on the details of the size and number of arrays and how many panels were identifiable by other means.

                                five.five.six, I would probably suggest in this order:

                                1) camera, selfie stick. (You might be able to get the numbers on the top of the optimizers this way. There are labels on both top and bottom.)
                                2) safely disconnect one string
                                3) temporary covering

                                Between 1 and 2, depending on your luck, you might be able to narrow it down to where only a minority are 'faked'.

                                The most important thing would be to keep careful notes throughout.

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