VoV generators connected to DB

**Generators???** · 31-Dec-19, 07:15 AM

Generator advice

Hi*all. Im looking for advice on setting up my generator to my db. We have constant power*outs*due to cable theft so i need a solution

*

For starters. Im not an electrician at all. I had an electrician install a transfer switch from the gen to my db with a welding plug + a*light showing when mains power has returned. Ie the typical setup most people have. So no backfeed risk

I have a honda eg6500cx. Ie a 5.5 kva petrol genset. I assume its VOV as neutral and live is "hot" with 110v each.

Ive been reading up on this issue as these cannot be connected to a*db legally due to VOV nature ( the electrician failed to*mention this... ). Now i*cant find a 5.5kva VOO generator in south africa and fitting a large diesel genset to overcome this is not affordable*nor wise as its overkill for my needs. A diesel genset idling with 10% load comes with its own issues

As i understand it the issues are as follows with a vov gen:

1 - EL wont trip as its only getting 110v via live if one does not*bind the E and N

2 - cant bind the N*and E*as this would make the appliances "earthed" ie risk of shock when touching fridge or the generator

Can someone that really knows this topic please guide me on the following in non electrician terms, ie how can i safely connect the gen

1 - what is the risk other than EL not working with my current setup

2 - ive read one*can install an isolation transformer between the gen and the db connection that effectively changes the feed from VOV gen side to VOO load side? Is this right? Will this solve the safety issue?

3 - some articles say just remove the center tap ie the gen alternator can be modified to make it VOO. Can this one be modified? Who can do this in gauteng? The alternator is 2 pole and the earth does not have the yellow link wire posted in some threads

4 - some say when you bond the N and E that the EL will work but then just install an earth spike. Some say just install and earth spike and use as is.

5 - failing all the above can one change.the alternator to one that is VOO? I know basically anything can connect.to a gx390 honda. Which alternator is VOO that is available in*SA that would fit? And where can this be done in jhb?

Thank*you for the*time. Advice will be greatly appreciated

**adrianh** · 31-Dec-19, 09:56 AM

Look at this historical conversation on this group.

230 volt generator with a V-O-V earth connection - The Forum SA

https://www.theforumsa.co.za/forums/showthread.php/9260-230-volt-generator-with-a-V-O-V-earth-connection

anyone know what one of these generators look like... also not a trick question...

**Generators???** · 31-Dec-19, 10:08 AM

Thanks ive seen this. It does not answer my questions

**adrianh** · 31-Dec-19, 10:35 AM

That conversation was between the local experts -

OK, maybe one of them has more to add.... we wait n see...

**Rifrug** · 31-Dec-19, 10:57 AM

I am no expert but I would bond neutral and earth at generator and install a earth spike before the earth leakage. In other words it is your alternative supply and will not be a problem the same as the municipality bond N and E at the transformer, your change over switch select alternative or grid. The voltage will then be 220V N to E. The earth leakage should work as normal. This should not be a problem for a COC as long as the test results are within limits.

**Generators???** · 31-Dec-19, 11:00 AM

I read that if you bond N and E on these generators then you risk livening up the chassis. Firdges etc

Does the earth spike solve this?

**Rifrug** · 31-Dec-19, 02:55 PM

Originally posted by Generators???

I read that if you bond N and E on these generators then you risk livening up the chassis. Firdges etc

Does the earth spike solve this?

Its the first time I hear about livening up the chassis, but if the chassis is earthed, the earth leakage will trip if leakage current goes above the 30mA tolerance. I personally believe in earth spikes, if done right, it allows for a shorter route to earth. But my main reason for a earth spike is when you have a additional supply like genny or solar than you also need a additional earth as part of your supply because the council might have a bad earthing system that your not aware of.

**Derlyn** · 01-Jan-20, 09:56 AM

Originally posted by Generators???

Hi all

Im looking for guidence re connecting my generator to my db. Its a honda eg6500 5.5kva. I heard that this is probably a vov generator and therefore its got a live L and N @ 110v each. Issue therefore being one cant bond the N&E as apparently my fridge will then bite me as its earthed. I also know the earth leakage wont trip as the 110v live wont trigger it as its currently set up

There arnt any VOO 5.5kva gensets that i could find..and putting in a large diesel genset is overkill plus it would stand and idle so that has its own issues plus the high costs

What im trying to find out is how can i SAFELY connect my gen to my db. I have a transfer switch etc already wired but the whole VOV earthing thing seems to be an issue

Id like someone that really knows their stuff to please guide me on the below ( english please im not an electrician )

- What are the risks running it as is? I know most people are running their generator as i am today
- Can one change the alternator on the genny to one that is VOO. If so what make and where can i get this done in gauteng? Engine is honda gx390
- will an isolation transformer (watever that is? ) solve the issue ito safety ( not burning the house down,removing the risk thay someone could get shocked )
- finally - some.people comment one can modify the generator by removing centre taps and all kinds of things - who can tell me if this can be done on my genset to make it VOO?

I would greatly appreciate help wrt the above

Thanks!

Happy New Year

I have delved into the alternator story quite deeply. So much so, that a local supplier of alternators now supplies both Portable Alternators (VOV) and Standby Alternators ( Not VOV ) It is also important to understand that a Standby Alternator not be used as a Portable Alternator. A standby alternator should have it's wheels removed, if it's the type that comes supplied with wheels and should have it's own earth spike hit in in close proximity to the unit.

Changing a VOV wound alternator to a standby alternator is quite a simple process, however, this should be done by the supplier so as not to effect any guarantees.

The procedure is as follows:

1. Disconnect the centre tap from the chassis and insulate this wire (NB !) so there's no chance of it touching the chassis in future. The alternator does not need to be
stripped in order to do this. On most units, this wire is quite easily located where it is connected to the chassis.

2. Connect the neutral onto the chassis where the centre tap was previously connected, together with an earth wire to the earth spike.

3. You are ready to go and now have a Standby Alternator that can be legally connected to the DB via a change over switch.

When buying an alternator, keep in mind The Consumer Protection Act.
Section 55 of the act is about the consumer's rights to safe, good quality goods and reads as follows:

(3) In addition to the right set out in subsection (2)(a), if a consumer has specifically informed the supplier of the particular purpose for which the consumer wishes to acquire any goods, or the use to which the consumer intends to apply those goods, and the supplier -

(a) ordinarily offers to supply such goods; or
(b) acts in a manner consistent with being knowledgeable about the use of those goods,

the consumer has a right to expect that the goods are reasonably suitable for the specific purpose that the consumer has indicated.

It was only after the local supplier of alternators was shown the above act that they deemed it necessary to do the necessary.
It would be great if all suppliers were to do the same, however, I don't think it's gonna happen.

Cheers and peace out

Derek

**Generators???** · 01-Jan-20, 10:53 AM

Hi derek thanks a lot. Do you know where i can get this done in pretoria/jhb? Ie alternator modified

**Derlyn** · 01-Jan-20, 06:24 PM

Originally posted by Generators???

Hi derek thanks a lot. Do you know where i can get this done in pretoria/jhb? Ie alternator modified

Unfortunately not, brother.

Derek

**Generators???** · 01-Jan-20, 07:45 PM

Ok thanks. I sure someone here will know who i can contact re this

Ps who is the local alternator supplier you mentioned that now sells VOO as well?

VoV generators connected to DB

VoV generators connected to DB

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