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.
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 at 07:10 AM.
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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.
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?
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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?
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.
https://www.buffalocity.gov.za/folder.php?id=sSWeUsCZg
Peace out ... Derek.
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.
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
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@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
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