Small generator connection

[ians]

So many calls from desperate customers ...wanting to connect a small genrator to the house.

NO VOV GENERATORS CAN BE CONNECTED TO THE HOUSE DIRECTLY.

So I came up with a solution which I beleive is the safest way to do it without rewiring the entire house and fitting dedicated and non dedicated supplies.

This is how I have wired my own house.

Drilled a hole into the bottom of my meter ... installed 2 x 25 mm adaptors with a short piece of 25 mm sprag (this must be sealed if out in the weather)

Mounted a 12 way IP 67 DB.

The DB is fitted with an idicator light to shows the mains power is on ... a 63 A changeover switch (the meter has a 60 amp breaker)

16 mm wires from the meter to the top of the changeover switch.

16 mm wires from the bottom of the changeover switch back into the meter box which are joined to the house wires feeding the main DB using ferruls.

A 32 amp wall mounted male plug top is installed belew the changeover DB (fitted with a cap when not in use)

4 mm wires feeding from the plug into the changeover DB to the doublew pole 32 amp geyser combo type breaker/ isolator then from the combo to the generator input on the changeover switch... the neutral wire is bonded at the input side of the combo breaker/isolator to the main earth with an indicator light mounted next to the changeover switch to indicate when the genertor is feeding power ... there is also a voltmeter and 100 amp panel meter mounted on the side of the changeover panel for the customer to monitor the load draw from the house ... so that he can choose which circuits he wants to power.

The generator (8 kva) has 10 m of 4 mm trailing cable (for extra protection) connected directly to the 30 amp breaker mounted in the generator via a compression gland with a 32 amp female plug coupler at the other end ... I didnt fit a 32 amp socket outlet on the generator because during the last load shed ... the vibration from the generator caused the plug to eventually fall out ... causing a few issues.

I cant think of a safer easier way to do this ... without it becoming a massive cost to customers.

It is a manual changeover and circuits in the house must be isolated to prevent overloading ... which can be monitored by the current meter mounted on the side of the changeover panel.

We will be upgrading the main DB soon ... ther ewill be a voltmeter and ammete rattached to the front so easy power management.

[ians]

I have a minor concern ... the indicator lights and voltmeter don have fused protection ... but I am thinking maybe it is not reuqired because they are only 100 mm long 1.5 mm wires ... in the fault free zone. ... I will phone a friend to verify this ... other wise 3 fuse holders with 3 1 amp fuses should be fine.

[ians]

Installation complete ... I didnt bond the neutral and earth ... did a few tests and it indicated no earth ... so I decided to bond in the changeover DB ... I did consider doing it in the generator where I connect ed the 4 mm trailing cable ... but was concerned about the fact that a generator used and a mobile units doesnt have the N and E bonded.

Instead I ran the neutral to the earth stud and from there to the the top of the 32 amp combo breaker.

A note ... I took the cable from the meter circuit breaker ... down to the 32 amp plug and back up into the meter ... then realised that while the generator was running the meter was turning ... so I had to change it ... out the meter load side of the meter ... down to the changeover switch and back up to the meter joined using ferulles.

Customer very happy ... next step to replace the main DB (we have rewired the house and made the house smart comapatible ... ie neutral in the switch boxes) ... fit an inverter and bactteries ... then at a later stage ... solar panels.

[GCE]

Installation complete ... I didnt bond the neutral and earth ... did a few tests and it indicated no earth ... so I decided to bond in the changeover DB ... I did consider doing it in the generator where I connect ed the 4 mm trailing cable ... but was concerned about the fact that a generator used and a mobile units doesnt have the N and E bonded.

Instead I ran the neutral to the earth stud and from there to the the top of the 32 amp combo breaker.
.

Not sure if I misunderstand what was said above.

Joining neutral and earth at the end of the trailing cable or at the changeover DB is basically the same thing.
If in the change over DB , do I then understand that when running on incoming municipal supply the earth and neutral is bridged in your DB as well ?

[ians]

An interesting article

https://www.ee.co.za/article/safe-us...-supplies.html

[ians]

Unfortunately not everyone has R30K plus to throw at generators ... including myself ... I connect my contractors generator to my house ... I have inverters etc ... and have no plan in the future to throw R30k at a generator .. if anything it will be solar and lithium or better batteries.

Secondly as you mentioned ... most decent sparkies steer clear of these small jobs ... in fact the last time I looked at one was more then 10 years ago ... however there is a huge market for someone to connect these units.

Lastly if you see what I saw today ... you will understand why it is important for us to rather do the job ... I had "generator installer" install a mobile unit on one of my customers properties ... holy crap ... no matter how bad I did the job ... it would have still been safer than the way this job was done.

Starting with the male plug coupler fitted to the generator

[ians]

I will try expalin a little better.

At the generator - I drilled ahole into the side of the power box (with the plugs switches ... etc) ... fitted a gland and connected the neutral to the neutral wire from the alternator and the earth wire to the earth wire from the alternator and the earth stud on the generator ... the live I connected to the bottom of the 30 amp circuit breaker (no bonding between N-E)

The trailing cable has a 32 amp socket outlet attached on the end (no bonding N-E) ... which plugs into the wall mounted plug top.

The wall mounted 32 amp plug top - the neutral and earth go to the earth bar in the changeover DB ... then the neutral goes from the earth bar to the N at the top of the 32 amp combo breaker ... the live goes from the plug top pin to the L on the top of the 32 amp combo ... then from the bottom of the combo breaker to the G / GN input on the changeover switch and to the indicator light.


I was going to fit a 32 amp plug socket in place of one of the 16 amp 164-1 sockets and wire it to the breaker directly with 4 mm wire ... however after my incident the other night during load shedding ... my plug fell out the generator ...causing all sorts of problems because it didnt just fall out ...it worked loose slowly.

I was going to bond the neutral and earth at the generator in the power box ... but I decided against it ... the reason ... generators are supplied without it bonded ... as I am typing I am thinking maybe this generator is VOV ... I will go back and check tomorrow and measure the voltage between L-N-E/ L-E. ... just to make sure ... from what I understand ... if the generator is not VOV ,... the N and E should be bonded at the alternator ?

[ians]

The question to the supplier of the generator is pretty simple can you connect the generator to the electrical installation yes or no ... for safety reasons ... all generators connected VOV format should be clearly identified with a notice on the unit.

It would save a lot of confusion.

[skatingsparks]

The question to the supplier of the generator is pretty simple can you connect the generator to the electrical installation yes or no ... for safety reasons ... all generators connected VOV format should be clearly identified with a notice on the unit.

It would save a lot of confusion.

But still people will connect to there house....

Besides most suppliers don't understand the implications of connecting a VOV generator. They just want the sale. They have been told - all that is needed is a change over switch.

I use the analergy of " the seat belt" with my customers and their Grip/Honda/whichever generator.

Yes, you can drive your car without a seat belt. But sure as S*&t, if you had a crash, you are going to want it.

Earth is your seat belt, Earth leakage is your airbag. If you crash in a car you would want both seat belt and air bag.

If you (or your family) are getting a shock, pretty sure your would want a functional earth and earth leakage.

Would you drive on these roads without your seat belt....

I then ask them "Still want to connect a generator without earth and functioning earth leakage?". If they do then they must get someone else in

Besides, insurance companies have caught onto generator connected incorrectly.
I know of one person who wasn't paid out because of this. Small electrical fire - board went into melt down, nothing major.
I'm pretty sure it was a loose neutral. Nothing to do with the generator set up.

Refused to pay out.

[Derlyn]

My simple generator test box.

If only the left side lights up when plugged into the generator output, then we are ok for connecting to installation.

If both light up then I walk away. It's also easier using the lamps than a multimeter to explain to the prospective client why it will not work.

Peace out ... Derek