Generator connection

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  • Dave A
    Site Caretaker

    • May 2006
    • 22807

    #61
    And if there is no center tap to earth?

    I can't help wonder if many of the gensets out there are not actually V-O-V with a center tap to earth, but actually "safe supply" arrangements.
    Last edited by Dave A; 01-May-18, 07:10 AM.
    Participation is voluntary.

    Alcocks Electrical Services | Alcocks Pest Control & Entomological Services | Alcocks Hygiene Services

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    • JacquesPN
      New Member
      • Jan 2016
      • 7

      #62
      Originally posted by Dave A
      And if there is no center tap to earth?

      I can't help wonder if many of the gensets out there are not actually V-O-V with a center tap to earth, but actually "safe supply" arrangements.
      As I said (save for a few special builds) almost every generator under 7KVA is V-O-V (PNP). they are not designed for use as standby sets but rather as temporary supply via a lead. As long as your not connecting to the DB or feeding into the building supply in any other way these are legal, but the second you feed into the building they become illegal because there is no way you can bond the Neutral to the earth.

      What amasses me is that there are so many of these illegal installations, and they are being done by registered electricians and neither the ECA or the ECB have made any effort to stop this or to advice the public of the dangers.

      Comment

      • Dave A
        Site Caretaker

        • May 2006
        • 22807

        #63
        With respect, that doesn't answer the question.

        My 5.5 kVA generator doesn't have a center tap to earth.
        In fact there is no connection between the earth point of the generator and the single phase supply it provides. (Insulation test between earth and phase exceeds 1 Mega Ohm).
        Am I prohibited from connecting this generator to an electrical installation as an alternate supply?
        Participation is voluntary.

        Alcocks Electrical Services | Alcocks Pest Control & Entomological Services | Alcocks Hygiene Services

        Comment

        • Leecatt
          Silver Member

          • Jul 2008
          • 404

          #64
          I have been asked to connect up a generator which I have not seen yet and this was going to take place this morning.
          I have never connected a generator before because of the absolute minefield it has become, not to mention the confusion. However, I have taken an interest recently due to today's job and I am just wondering, are the regulations the same in version three of 10142—1 as they were in version 2, regarding the generator? I have yet to purchase version 3.
          Also,I noticed on the SABS website that there is a separate PDF available which deals entirely with the installation of generators. Has anybody purchased this separate PDF and and does it give clear concise instructions?
          To make a mistake is human, to learn from that mistake is knowledge and knowledge is strength.

          Comment

          • Derlyn
            Platinum Member

            • Mar 2019
            • 1747

            #65
            Check your local municipality by laws as well.

            Here in our valley we need to apply and get permission from the Munic to do a generator installation.
            Technical specs of generator, circuitry and drawings of same are needed to accompany the application.

            Attached is a copy of our by laws, but I suggest you check those in your area before doing the job.




            Peace out ... Derek.

            Comment

            • GCE
              Platinum Member

              • Jun 2017
              • 1473

              #66
              Originally posted by Leecatt
              I have been asked to connect up a generator which I have not seen yet and this was going to take place this morning.
              I have never connected a generator before because of the absolute minefield it has become, not to mention the confusion. However, I have taken an interest recently due to today's job and I am just wondering, are the regulations the same in version three of 10142—1 as they were in version 2, regarding the generator? I have yet to purchase version 3.
              Also,I noticed on the SABS website that there is a separate PDF available which deals entirely with the installation of generators. Has anybody purchased this separate PDF and and does it give clear concise instructions?
              Besides a note added under 7.12.3.1.3 it is basically identical
              I have not seen the generator installation standard


              7.12.3.1.3 Where alternative supplies are installed remotely from the
              installation, or from one another, and where it is not possible to make use of
              a single neutral bar or neutral conductor which is earthed, the neutral of each
              unit shall be earthed at the unit and these points shall be bonded to the
              consumer's earth terminal (see 6.12.4). The supply from each unit which
              supplies the installation or part of the installation, shall be switched by means
              of a switch that breaks all live conductors operating substantially together (see
              figures P.2 and P.4), to disconnect the earthed neutral point from the
              installation neutral when the alternative supply is not connected (see also
              6.1.6).
              NOTE Where four pole switching is implemented, consideration should be given to use
              overlapping neutral switching devices
              .

              Comment

              • Derlyn
                Platinum Member

                • Mar 2019
                • 1747

                #67
                Tested a generator this morning. The specific model ...... Ryobi rg 6900K.

                Results as follows:

                No load ..... L - N 235V ; L - E 160V ; E-N 75V

                With load .... L - N 235V ; L - E 235V ; E-N 0V

                Is there anyone who can explain this. I'm wracking what's left of my brain cells but cannot understand it.

                Peace out .. Derek

                Comment

                • rh1
                  Junior Member
                  • Dec 2017
                  • 16

                  #68
                  Originally posted by Derlyn
                  Check your local municipality by laws as well.

                  Here in our valley we need to apply and get permission from the Munic to do a generator installation.
                  Technical specs of generator, circuitry and drawings of same are needed to accompany the application.

                  Attached is a copy of our by laws, but I suggest you check those in your area before doing the job.




                  Peace out ... Derek.
                  I am in Cape Town but a direct customer of Eskom, would COCT by-laws still apply to me?

                  Comment

                  • Dylboy
                    Gold Member

                    • Jun 2020
                    • 777

                    #69
                    Originally posted by Derlyn
                    Tested a generator this morning. The specific model ...... Ryobi rg 6900K.

                    Results as follows:

                    No load ..... L - N 235V ; L - E 160V ; E-N 75V

                    With load .... L - N 235V ; L - E 235V ; E-N 0V

                    Is there anyone who can explain this. I'm wracking what's left of my brain cells but cannot understand it.

                    Peace out .. Derek
                    Best guess is the voltage regulator stuff and perhaps a form of induced EMF on the N and E etc. A generator needs to run on load as far as I understand to run correctly.

                    I have been told if a generator is producing more than the load it does not like it as it has to keep revs up and not stall but then too much voltage applied etc.

                    Anyway that's my best so far as to why seeing voltages like that. Also then when it's under load then the genny i believe is then not VoV which is great

                    Sent from my SM-N960F using Tapatalk

                    Comment

                    • Derlyn
                      Platinum Member

                      • Mar 2019
                      • 1747

                      #70
                      @Dylboy. Yes, not vov for sure. I've checked if vov then the voltage is split 50/50 whether there is a load or not.

                      Also, I cannot see 3 thick leads coming from the stator. Only 2, live and neutral. On vov wound, there are 3 thick leads coming from the stator with one of them (centre tap ) connected to earth.

                      Gonna do more tests on Monday.

                      Gonna connect it to installation and see if earth leakage works as it should.

                      Peace out .. Derek

                      Comment

                      • Dylboy
                        Gold Member

                        • Jun 2020
                        • 777

                        #71
                        Originally posted by Derlyn
                        @Dylboy. Yes, not vov for sure. I've checked if vov then the voltage is split 50/50 whether there is a load or not.

                        Also, I cannot see 3 thick leads coming from the stator. Only 2, live and neutral. On vov wound, there are 3 thick leads coming from the stator with one of them (centre tap ) connected to earth.

                        Gonna do more tests on Monday.

                        Gonna connect it to installation and see if earth leakage works as it should.

                        Peace out .. Derek
                        Ah brilliant! well hope will all be alright once installed! Keep us posted if you can please on the outcome.

                        Will try find out more why you got those reading on no load as well

                        Sent from my SM-N960F using Tapatalk

                        Comment

                        • GCE
                          Platinum Member

                          • Jun 2017
                          • 1473

                          #72
                          Originally posted by Derlyn
                          Tested a generator this morning. The specific model ...... Ryobi rg 6900K.

                          Results as follows:

                          No load ..... L - N 235V ; L - E 160V ; E-N 75V

                          With load .... L - N 235V ; L - E 235V ; E-N 0V

                          Is there anyone who can explain this. I'm wracking what's left of my brain cells but cannot understand it.

                          Peace out .. Derek
                          A multi meter has a High Impedance and will tend to pick up " stray " voltages - If you used a meter with low impedance ( duspol tester) you would find the reading would give the same as on load readings

                          Comment

                          • Derlyn
                            Platinum Member

                            • Mar 2019
                            • 1747

                            #73
                            Thank you GCE.

                            I'm going to dig out my Manox from appy days and check it again on Monday.

                            Enjoy the rest of the weekend.

                            Peace out .. Derek.

                            Comment

                            • Leecatt
                              Silver Member

                              • Jul 2008
                              • 404

                              #74
                              Originally posted by Derlyn
                              Thank you GCE.

                              I'm going to dig out my Manox from appy days and check it again on Monday.

                              Enjoy the rest of the weekend.

                              Peace out .. Derek.
                              Hmmm. Now you've inspired me to dig out my Avo Meter. I actually found a battery for it, must buy that.

                              Sent from my SM-A705FN using Tapatalk
                              To make a mistake is human, to learn from that mistake is knowledge and knowledge is strength.

                              Comment

                              • ians
                                Diamond Member

                                • Apr 2010
                                • 3943

                                #75
                                Comments are based on opinion...not always facts....that's why people use an alias.

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