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    PV & Podco at the same time

    Is it legal to have 2 sources of power feed circuits in a house. For example, when the Power goes off the photovoltaic will energize a small 110 volt panel with a select few circuits. The HO then wants the 7000 watt manual generator to be able to be cranked up and feed other circuits in the house. I don't think this is legal.

    I proposed that the 7kw gen could feed the PV panel and the gen panel. With the use of 2 transfer switches I think this can be done.

    What the ho wants to do is use the PV when there is an outage however if the power is out for more than 36 hours she wants to be able to use the gen. to energize the wine cooler, etc that are not part of the PV.

    Am I correct in stated that the first scenario is not compliant?

    I guess I am thinking 225.30-- are the gen & PV considered feeders at this point?
    Last edited by Dennis Alwon; 05-12-08, 04:49 PM.
    They say I shot a man named Gray and took his wife to Italy
    She inherited a million bucks and when she died it came to me
    I can't help it if I'm lucky

    #2
    Originally posted by Dennis Alwon
    are the gen & PV considered feeders at this point?
    Yes they are feeders, services only come from utilities.

    I don't see and issue, any multiple sources will only become more common with solar and wind power.

    Comment


      #3
      multiple sources will only become more common

      Maybe someone already makes a battery-backed-up programmable microprocessor control that drives large relays to do this kind of thing.
      Inputs to this box would be the HO's program and sensors so it knows where the current is going.

      Comment


        #4
        dennis

        what type of PV system?

        Comment


          #5
          Assuming a normal style of PV installation, the PV feeds (via the inverter) power back to the "grid" via breakers in a panel. When PoCo power is lost the inverter will shut down to prevent grid backfeeding and islanding. So you will somehow have to isolate the panel that the PV is fed to, and then inform the inverter that it can start producing power again. And when poco power comes back up, reverse the process. Sounds like a PLC needed.

          Also, when the genset is running, should it feed the PV supplied panel, and the PV continues to supply power helping the genset out? From the perspective of the PV panel and inverter, this is equivalent to the PoCo coming up again.

          Other than that gotcha, the other panel and the genset is just standard fare.

          Not impossible, but requires a local power source; most PV systems have batteries which would do the job.

          Comment


            #6
            I am not installing the PV system as I know very little about them. We have a company that will install their end. I need to provide a sub panel with the required circuits. The way I see it I think we are going to supply an ATS that will feed the PV circuit panel and another sub panel with the extra circuits.

            From there drawings , which are just sketched on paper it looks as if they have two Iota ATS (whatever that is).

            My biggest question was whether you can energize different circuits in a house from 2 different power sources--- the generator and the PV at the same time as long as they don't control the same circuits. I don't think we will be doing this but was curious if it was compliant.
            They say I shot a man named Gray and took his wife to Italy
            She inherited a million bucks and when she died it came to me
            I can't help it if I'm lucky

            Comment


              #7
              Originally posted by Dennis Alwon

              My biggest question was whether you can energize different circuits in a house from 2 different power sources--- the generator and the PV at the same time as long as they don't control the same circuits. I don't think we will be doing this but was curious if it was compliant.
              Sure can. As long as neither system is back feeding the grid. It really depends on the PV system though... a stand alone pv system with batteries would work. A grid-tie PV system does back feed the grid but it will have a lockable disconnect by the meter if the poco wants to lock them out in the event the home owners try to power it up during a power outtage & the generator just needs a transfer switch.
              Dave

              "Don't wire like my brother"

              Comment


                #8
                Dennis
                I believe that 225.30(A) permits the multiple sources you are describing to be a permitted installation.
                Instructor, Industry Advocate

                Comment


                  #9
                  Originally posted by Dennis Alwon
                  I am not installing the PV system as I know very little about them. We have a company that will install their end. I need to provide a sub panel with the required circuits. The way I see it I think we are going to supply an ATS that will feed the PV circuit panel and another sub panel with the extra circuits.

                  From there drawings , which are just sketched on paper it looks as if they have two Iota ATS (whatever that is).

                  My biggest question was whether you can energize different circuits in a house from 2 different power sources--- the generator and the PV at the same time as long as they don't control the same circuits. I don't think we will be doing this but was curious if it was compliant.
                  An ats is an automatic transfer switch so it seems to me they are going to feed the two xfer points pv and poco so it seems ok to me as long as discos are provided and labeled this is no different than having a standby generator.
                  The tail does NOT wag the dog.

                  Comment


                    #10
                    If it is a 'grid tied' PV system it will have a controller that prevents back feeding the utility during a utility power outage.

                    If it is a stand alone system a back feed is imposable.

                    Comment


                      #11
                      The PV system will feed back to the power company under normal situations. It will have large Batteries for storage and will feed the house in times of podco outage. The generator will come on if the power is out for more than 24 or 36 hours to feed the pv panel and the extra circuits. This is a manual generator. 7000 sq. foot house with heated Towel bars that cost $1200 each and they didn't want an automatic generator. We could have provided a 30 kw gen. and an energy management system to do the entire house for $22,000. They didn't want it. Wheel out that gen. every time they need it....

                      Thanks for the responses. It seems we can do what I thought we couldn't but I think we are going the route I posted most recently.
                      They say I shot a man named Gray and took his wife to Italy
                      She inherited a million bucks and when she died it came to me
                      I can't help it if I'm lucky

                      Comment


                        #12
                        Dennis.,

                        The only object i have is the storage batterys i just hope the owner will realized that the batteries need ventation for it.

                        But otherwise as what other been talking about they are right on the target with it due more and more solar and wind turbine is getting more common nowdays.

                        Merci,Marc
                        Marc
                        master electrician
                        Wisconsin and Paris France

                        "Pas de problème, il marche n'est-ce pas?" (No problem, it works doesn't it?)

                        Comment


                          #13
                          Originally posted by Dennis Alwon
                          The PV system will feed back to the power company under normal situations. It will have large Batteries for storage and will feed the house in times of podco outage.
                          Just to note that this may not be as simple as stated, you need either an inverter specifically designed to do this job, or some fancy wiring.

                          Would be interested in what the inverter is.

                          Comment


                            #14
                            Originally posted by dbuckley
                            Just to note that this may not be as simple as stated, you need either an inverter specifically designed to do this job, or some fancy wiring.

                            Would be interested in what the inverter is.
                            I don't know what they are using although I know it is an inverter. Other than that I am not sure what they are supplying. I will try & get more info.
                            They say I shot a man named Gray and took his wife to Italy
                            She inherited a million bucks and when she died it came to me
                            I can't help it if I'm lucky

                            Comment


                              #15
                              Originally posted by dbuckley
                              Just to note that this may not be as simple as stated, you need either an inverter specifically designed to do this job, or some fancy wiring.

                              Would be interested in what the inverter is.
                              The NEC requires an inverter or AC module listed for that purpose and requires that it automatically prevents a back feed into a dead utility.

                              690.60 and 690.61

                              In the next few weeks I should be installing a 75 KW PV system that will be tied into the utility. Any 'extra' power will be sold back to the utility.

                              Comment

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