VOV generators

[Tonye]

I know this topic has been dealt with on numerous occasions but feel we need to make all aware of the regulations & dangers of connecting a VOV generator to an existing fixed electrical installation.

As load shedding is again part of our daily lives, people are reverting to generators for backup power.
Please be advised that most portable generators sold in SA are VOV wound and may not be connected to a fixed electrical installation.

SANS 10142-1 states in clause 7.12.2.7 that a 230 V generator with a V-O-V earth connection (centre tap on winding which is earthed) shall
not be connected to a fixed electrical installation. Such a generator may only be used as a free-standing unit to provide power to specific appliances
Read more at

http://www.prellexpower.co.za/index.php/backup-power/backup-power-regulations

That been said, there are many companys connecting them with a change over switch to fixed installations.
Should an incident occur, all involved parties will be investigated and the homeowner could attract liability if
the installation is not safe or is not correctly used.
It could also invalidate the insurance on the property.

Note: Remember that any alternate power installation must be executed by a person registered with the DoL.
The registered person must issue a CoC upon completion of the electrical installation.

[AndyD]

I think part of the problem is that it's not easy for an end user/customer to identify the winding arrangement of a generator and they're often mis-sold as being suitable for home power back-up when they're not.

As a rule of thumb any portable contractors type generator that comes with a steel tubular frame is not suitable for wiring to a DB.

[ians]

Try tell the customer...like not being allowed to walk on a freeway...there are bus stops on the N2 and various other freeways/national highways...you are not going to stop it...somebody needs to come up with a solution...soon.

The way to overcome this problem at the moment...you install the change over switch and fit a plug...it is not your problem what is connected to the plug.

[Leecatt]

Thank you for raising this topic. I have veered away from working with generators due to my ignorance on the subject. I am in a dark place with this subject and was hoping the thread may be revived and some clarity brought up around this subject.
TIA

[ians]

Load shedding stage 4 yesterday bought out all the genrators again ... they are everywhere ... on wheels ...at the SPar shop ... at the wholesaler ... at the neighbours ... 90 % of the connection ... just a plug on the outside wall ... 10% with changeover switch and dedicated DB's.

I have 2 installation this week and ton more enquiries for generator and inverter installations ... in fact so many that I have decided to go register as a reseller at a few of the inverter suppliers.

One thing I will be adding to the changeover switch (63 amp) and plug (32 amp it covers most small generator) ... a current clamp maybe even a voltmeter ... so that customers can see how much load is on the generator as they reset the circuit breakers.

VOV ... COC HOD ... it doesnt matter what the customer plans to connect to the socket ... its not your problem ... just like the electrical installation ...its not the electricians responsibilty ... it is up to the owner to make the right choice ... just make sure you put a note in your invoice "VOV generators not to b used".

[ians]

I am going to do a few mods to the current setup ... the easiest way to do it ... in this example a 60 amp single phase supply.

Mount a weather proof DB next to or below the meter box.

Fit a changeover switch to suit the meter circuit breaker ... in this case a 63 amp.

fit a 25 amp double pole breaker next to the changeover switch ( overload protection for the genrator ... a new addition)

fit a panel mount voltage and current meter next to the breaker ... and an indicator light if you feel the meter is not good visual indicator

Mount a 32 amp weartherproof male socket outlet below the weather proof DB ... even if out the weather ... it better with the cap over the plug pins.

Ready for most generators.

Please feel free to add a better solution if you have one.

[ians]

For those who feel it is safer to fit a Za plug ... feel free to replace the 32 amp with Za socket ... so that you dont have to use an extension

[ians]

The generator arrived ready to connect ... an interesting note on various locations on the generator

"Manufactured according to SANS 1007:2010 STANDARDS"

7500 watts

PF 1

To make sure everything is safe ... labels ... lables and more labels.

The customer asked why I didnt connect the cable to the plug on the 16 amp socket outlet on the front of the generator ... but instead directly to the circuit breaker on the generator ...via a gland ... the the 16 sockets are only rated to 16 amps and therefore cannot carry the full 7500 watts (32 amps).

I am wondering if it is not a good idea to knock a spike into the ground below the changeover switch and bond the wire from the spike to the supply earth at the same point where I connect the neutral from the socket to the mains earth ... it seems pointless ... but rather make it look like I know what I am doing.

[ians]

By the way the generator is brand new ... it must be illegal because it has 2 x 3 pin SANS 164-1 socket outlet next to each other and no ZA plug provided

[ians]

Rollling out the stores as people struggle to stay in bussiness with stage 4 load shedding ... and talk of stage 6 ... how do people know if these are legal or not?

YES IT IS DANGEROUS TO FIT A PLUG TOP ON EACH END OF THE EXTENTION CORD AND PLUG ONE INTO THE GENERATOR AND ONE IN THE SOCKET OUTLET IN YOUR HOUSE.

https://www.builders.co.za/Tools-%26-Protective-Wear/Power-Tools/Machinery/Generators/Ryobi5-5-kVA-4-Stroke-Petrol-Generator/p/000000000000460483

https://www.builders.co.za/Tools-%26-Protective-Wear/Power-Tools/Machinery/Generators/Grip-5-0Kva-Petrol-Recoil-Start-Generator/p/000000000000643611

[Derlyn]

Hi Ian

Your url's refers.

https://www.builders.co.za/Tools-%26...00000000643611[/QUOTE]

I can tell you with confidence that this Grip alternator is NOT VOV wound and IS suitable for connecting to a domestic installation.

I have done a number of generator installations and the only one that I have found that is suitable is the Grip.

Cannot vouch for the Ryobi. Haven't checked it out yet, But the Grip is ok.

Peace out ... Derek

[Leecatt]

Grip is warranted by Gentech Industries. I called them yesterday and asked if it was a V-O-V wound unit. He had to check the specs and came back with the info that it is indeed V-O-V.

[Derlyn]

Instead of taking hi's word, start one, connect a load to it and use your multimeter to measure output voltages.

I've dealt with many clients having Grip alternators and according to the readings, not one of them has been vov wound.

I've also spoken to many guys selling generators and if you ask them if a particular unit is vov wound, they don't know what you're talking about.

Rather do the multimeter test to confirm. Just don't do it without a light load connected to the output because the readings can then be deceiving.

[Leecatt]

I eventually purchased a MAc Afric 7.5kw Generator from Ardendorff last week and ran it with extensions. I must say that their aftersales service is second to none. That aside, I have been in contact with their "go-to guy" and asked him if the unit is a V-O-V wound generator, here was his reply:

" Good day Lee
The machine is not a VOV it does normally have 70 v on neutral but the electrician will be able to sort that out with a floating neutral "

After explaining that I am the electrician I got the next email reply.

"Hi Lee,
As discussed telephonically, you requested we just put in writing a way forward to get your neutral line below 24V in accordance with SANS10142. This is a fairly simple process and does not void your warranty.

OF the 2 lines connected on the connector block at the back of the alternator housing, you will need to bridge the neutral line to the earth pole on the back of the alternator housing. This will give you 230V between live and neutral and 230V between live and earth, while your neutral line will register about 2 to 3 volt. "

I will be exploring this sometime when it warms up but in the meantime I would appreciate any feedback you guys may have.
It is proving extremely difficult to get a wiring diagram out of them

Regards
Lee

[Derlyn]

Hi Leecatt

Check out this attached thread. There's a photo of exactly how I've been doing it all the time, successfully.

The bridge can be seen. It's the black wire with yellow lugs.

All the generators that I've opened so far are identical. Only the branding that differs.

Just remove the round end cover of the genny and it's easy peasy.

Tip: There are 2 thick wires coming from inside the stator. The brown is live. White is neutral. Just bridge the white to earth.

Cheers.

https://www.theforumsa.co.za/forums/showthread.php/18004-Generator-connection/page9?highlight=vov+generators