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  • #46
    Originally posted by J.P.M. View Post

    I'd respectfully suggest that the reality may be a little less dichotomous that they will or will not always respond in the same way.

    It also seems, from what you reference, and no real surprise to me that the probability exists that firefighters, like electricians and others assume a circuit is always energized, and that personnel protection systems will fail and protect themselves first.

    I, perhaps more than most, am about completely cynical that most things peddled and crammed down people's throats like RSS, while well intentioned, quickly turn into profit centers for leaches. But I've also got faith that human nature, particularly the preservation part of it, will be more inclined, however slight, to act when there is at least a potential path to greater personnel safety made possible by the presence of an RSS.

    Maybe any first responders reading this thread would care to offer an opinion more informed than mine.
    I would have to think that any RSS proposals are born from requests/concerns from first responders and linemen rather than some marketing think tank for increased profits. Having dealt with many gov't agencies I have found that the reason may be obscure and the applicable situation improbable but there is a reason.

    Not unlike an HOA telling people what paint colors to use on their doors.

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    • #47
      Originally posted by DrLumen View Post

      I would have to think that any RSS proposals are born from requests/concerns from first responders and linemen rather than some marketing think tank for increased profits. Having dealt with many gov't agencies I have found that the reason may be obscure and the applicable situation improbable but there is a reason.

      Not unlike an HOA telling people what paint colors to use on their doors.
      As I wrote, seems to me lots of things start with good intentions. It's the leaches who see those attempts at good intentions that turn them into what often wind up as bureaucratic profit centers. RSS seems a good idea in principle. The reality may be that there are other ways to accomplish the same ends, but once established, the status quo (RSS ??) is hard to un-entrench or modify except to add more bureaucracy. Happens all the time.

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      • #48
        Originally posted by DrLumen View Post

        I would have to think that any RSS proposals are born from requests/concerns from first responders and linemen rather than some marketing think tank for increased profits. Having dealt with many gov't agencies I have found that the reason may be obscure and the applicable situation improbable but there is a reason.

        Not unlike an HOA telling people what paint colors to use on their doors.
        Here is an article mentioning the concerns of fire fighters for roof mounted solar pv systems.

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        • #49
          Originally posted by SunEagle View Post
          I will continue with another question, is it worth the inconvenience to a homeowner to not get power from their PV system if the grid goes down due to a grid tie inverter shutting down to protect a POCO worker from getting electrocuted?
          Why are automatic standby generators allowed to run during a power outage, but a grid-tie solar system is not allowed to operate? I'm sure someone could come up with a way to isolate from the POCO just like is done with a standby generator.

          My understanding is a big reason that grid-tie inverters can't operate without the POCO is they depend on matching voltage and frequency to the POCO power. Maybe what I read is totally wrong on this.

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          • #50
            A lot of stuff in the NEC is pushed by equipment manufacturers because they profit off the sale of the more expensive gear required to meet the new codes. I bet manufacturers make more profit from an AFCI breaker than they make in total revenue from a regular breaker.

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            • #51
              Originally posted by reader2580 View Post

              Why are automatic standby generators allowed to run during a power outage, but a grid-tie solar system is not allowed to operate? I'm sure someone could come up with a way to isolate from the POCO just like is done with a standby generator.

              My understanding is a big reason that grid-tie inverters can't operate without the POCO is they depend on matching voltage and frequency to the POCO power. Maybe what I read is totally wrong on this.
              Who sais they can not? Mine does every time all the time.
              the reason that most grid tie systems shut down is that that is all they are capable of doing. To operate without the grid you need a more expensive bimodal inverter system.
              Last edited by ButchDeal; 10-12-2017, 07:55 AM.
              OutBack FP1 w/ CS6P-250P http://bit.ly/1Sg5VNH

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              • #52
                Originally posted by reader2580 View Post

                Why are automatic standby generators allowed to run during a power outage, but a grid-tie solar system is not allowed to operate? I'm sure someone could come up with a way to isolate from the POCO just like is done with a standby generator.

                My understanding is a big reason that grid-tie inverters can't operate without the POCO is they depend on matching voltage and frequency to the POCO power. Maybe what I read is totally wrong on this.
                Because Stand-By Generators ...
                a) are not ever tied into the grid
                b) are isolated via an auto or manual transfer switch
                c) are a Voltage Source, they create the own Voltage and their own Frequency
                d) may operate over a wide range of voltage and frequency

                Because Grid-Tie Inverters ...
                a) are tied into the grid via a circuit breaker
                b) typically do not have a transfer switch
                c) are Current Sources that FOLLOW the Grid Voltage and the Grid Frequency
                d) operate within a very narrow voltage & frequency, required for auto shutdown with grid shutdown or out-of-range

                Some (newer) Grid-Tie Inverters do provide an Off-Grid AC Power Outlet without a battery bank!

                But if you want STABLE off-grid electricity from a PV Array then you need a hybrid system with a battery bank ( ie clouds )
                Last edited by NEOH; 10-12-2017, 12:52 AM.

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                • #53
                  Originally posted by reader2580 View Post

                  Why are automatic standby generators allowed to run during a power outage, but a grid-tie solar system is not allowed to operate? I'm sure someone could come up with a way to isolate from the POCO just like is done with a standby generator.

                  My understanding is a big reason that grid-tie inverters can't operate without the POCO is they depend on matching voltage and frequency to the POCO power. Maybe what I read is totally wrong on this.
                  Along with NEOH's post, there is also the issue that in buildings with emergency generators, they have dedicated emergency circuits and a generator to match those possible loads. Batteries aside, I know that system won't work with PV as there would need to be some type of load shedding rules or mechanisms. You may want a HVAC, fridge, TV, some lights and computers to be on your off-grid PV emergency circuits. So, if it is cloudy and the PV inverter can't supply enough power, what should have priority for the power that is available? Not to mention possible damage to appliances not getting the needed power.

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                  • #54
                    Originally posted by reader2580 View Post

                    Why are automatic standby generators allowed to run during a power outage, but a grid-tie solar system is not allowed to operate? I'm sure someone could come up with a way to isolate from the POCO just like is done with a standby generator.

                    My understanding is a big reason that grid-tie inverters can't operate without the POCO is they depend on matching voltage and frequency to the POCO power. Maybe what I read is totally wrong on this.
                    A standby generator should also have a transfer switch which is required to isolate the power it produces from getting out onto the grid.

                    Now if the Solar Inverter people had made their equipment that included a way to totally isolate the inverter from the grid yet still work similar to the SMA secure power option yet be able to use all of the pv wattage instead of just 15 to 20amps worth we would not be having this conversation. But consider the extra cost to provide that isolation circuit.

                    The problem is that all POCO's required a grid tie inverter to shut down if there was an issue on the grid. That was much less expensive to provide then to have a complete fully rated transfer switch and much safer because transfer switches can be defeated which could lead to someone getting electrocuted.

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