Inverter/transformer neutral earth connection.

**Gtfast** · 03-Jul-23, 07:59 AM

Hi all
A friend has a Yamaha generator .
Internally it has no neutral to earth connection.
The Earth leakage will not trip when tested with EL tester .
There is also a polarity fault because one side of the winding is not connected to earth.
Where is the Protection.
One cannot connect neutral to earth externally.
He also has an inverter with the same setup.
What is the solution.
Some discussion would be appreciated.
Thank you

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**Derlyn** · 03-Jul-23, 09:23 AM

First thing to do is take some voltage readings with a load connected to the generator. L-N ?
L-E ? N-E ?

Report back..

**Thys LOW Elektries** · 05-Jul-23, 11:01 AM

Once the L-N, L-E, and N-E readings have been taken, a missing Star point will most probably be diagnosed.
Cheap over-the-counter generators and those bought at Makro and Game very seldom if ever a Star point or like they say "Neutral to Earth bond"
A star point will have to be created if there is none. Various discussions had been done on which way is best so I'm not going to comment on that issue.

**Thys LOW Elektries** · 05-Jul-23, 11:03 AM

https://www.theforumsa.co.za/forums/...backup-systems go read that if you have time Very informative

**Gtfast** · 05-Jul-23, 11:11 AM

Hi Thanks

That's the confusing thing.
I would consider it not a cheap Generator.

I am still waiting on voltages.

Why is no neutral earth bond provided.
The generator is like a safety supply????
Are we just not buying the correct Generators for house supply.

I will read further.

Thanks

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**GCE** · 05-Jul-23, 03:43 PM

Originally Posted by Gtfast

Hi Thanks

Why is no neutral earth bond provided.
The generator is like a safety supply????
Are we just not buying the correct Generators for house supply.

Yip - incorrect gensets being used from design and then generally also sizing , but in typical South African fashion we make a plan to make it work

SANS 10142-1
7.12.2.7 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.
NOTE Such a generator may be used as a free-standing unit to provide power to
specific appliances.

**Gtfast** · 05-Jul-23, 06:56 PM

Here are the voltages of the generator.

No load
L TO N. 232V
E TO N 3v
E TO L. 3V

With 300w load.
E TO N 11v
E TO L. 11v

Not sure about fault current if connecting neutral to earth.Will the generator not get damaged.

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**Derlyn** · 05-Jul-23, 08:42 PM

Ok. This generator is not vov wound.
Hopefully it is connected properly through a change over switch. If so, the earth and neutral can be bridged on the generator. I have done this many times with success.