No power!!!!

Lachdog · Jun 20, 2018

Hey guys n gals,

recently wired up a switchboard for a customer ( house had already been wired up by an electrician, 3 lighting curcuits, and 2 power circuits! All on rcd/mcb breaker combo's(rcbo's) ), it is being powered by a small generator(2000watts //10amps//240volts) but when main switch is flicked, then all other following rcbo's are turned on, no lights work, and only one power circuit works, i cant switch the 2nd power curcuit

on for some reason! The generator groans as soon as i flick the breaker on(almost like theirs load on that circuit, but everything inside is switched off!)

any help would be much appreciated! Cheers

ProDave · Jun 20, 2018

What dead testing have you done before energising the board?

binky · Jun 20, 2018

sounds like you've done something very wrong! As this is an off-grid system, is there anything like battery storage connected? Some pictures of the board would be good, and what earthing have you installed?

Lachdog · Jun 20, 2018

binky said:
sounds like you've done something very wrong! As this is an off-grid system, is there anything like battery storage connected? Some pictures of the board would be good, and what earthing have you installed?

Here is a link to the photo of the board. I should have taken a recent one this afternoon

, the feed is coming from the generator, just imagine an active(red) wired into the top of the 63amp main switch, earth(green/yellow) wired into the small earth bar, and a neutral(black) wired into the neutral bar. The house is earthed by an earth stake(earth rod)(running Multiple Earthed Neutral(MEN) earthing system)(Its just a 6mm earth cable from earth bar to neutral bar)

it is completely off the grid, generator is only power source.

https://s33.postimg.cc/4ylc1zre7/IMG_9901.jpg

Lachdog · Jun 20, 2018

Lachdog said:
Here is a link to the photo of the board. I should have taken a recent one this afternoon , the feed is coming from the generator, just imagine an active(red) wired into the top of the 63amp main switch, earth(green/yellow) wired into the small earth bar, and a neutral(black) wired into the neutral bar. The house is earthed by an earth stake(earth rod)(running Multiple Earthed Neutral(MEN) earthing system)(Its just a 6mm earth cable from earth bar to neutral bar)

it is completely off the grid, generator is only power source.

https://s33.postimg.cc/4ylc1zre7/IMG_9901.jpg

Here is another picture;

https://s33.postimg.cc/6hls3z9e7/IMG_9903.jpg

ProDave · Jun 20, 2018

To make it easier

IMG_9901.jpg.c997887ac6cd259435be0c91ffba9099.jpg

IMG_9903.jpg.c83cd83a4d7b45216e03973bd17ec076.jpg

It's a long time since we should have been using red and black on a new install.

That is clearly home made, and only a single pole "main switch" (which happens to be an mcb not a main switch)

None of that explains why it is not working. But you mentioned an "electrician" installed the circuits, so can you clarify what country you are in that still uses red and black?

Geoff1946 · Jun 20, 2018

The generator you describe probably couldn't trip any of those MCBs. You most likely have a short somewhere, (or a load above its capacity), and the generator is shutting down on its internal protection.

Lachdog · Jun 20, 2018

ProDave said:
To make it easier

It's a long time since we should have been using red and black on a new install.

That is clearly home made, and only a single pole "main switch" (which happens to be an mcb not a main switch)

None of that explains why it is not working. But you mentioned an "electrician" installed the circuits, so can you clarify what country you are in that still uses red and black?

Australia

Lachdog · Jun 20, 2018

Geoff1946 said:
The generator you describe probably couldn't trip any of those MCBs. You most likely have a short somewhere, (or a load above its capacity), and the generator is shutting down on its internal protection.

Thats what im confused about, the generator is way too small to produce the amount of amps to trip the mcb, if it was shorting wouldnt the rcd part of my mcb/rcd combo breakers trip!? Its as if their is a load on my second power circuit somehow(when i switch the breaker on, the geni groans and about 5secs later it kicks the power off that outlet)

roys · Jun 20, 2018

Generally speaking:

The RCD won't trip on a L to N short that is the function of a MCB to give the overload and short circuit between L to N fault.

The RCD protects against L or N faults to earth either via the wiring, environmental conditions, or the human body touching Live.

Rob. · Jun 20, 2018

They're all dp rcbos...

What's all this talk of mcbs and rcds?

ProDave · Jun 20, 2018

Rob. said:
They're all dp rcbos...

What's all this talk of mcbs and rcds?

His "main switch" is a single pole MCB

I would suggest as stated that there is a short on the second power circuit and the generator is current limiting. Check the wiring of that circuit very carefully.

The lighting circuits must have other faults if they don't work.

Murdoch · Jun 20, 2018

At least the Australians have the sense to use red and black

Rob. · Jun 20, 2018

ProDave said:
His "main switch" is a single pole MCB

I would suggest as stated that there is a short on the second power circuit and the generator is current limiting. Check the wiring of that circuit very carefully.

The lighting circuits must have other faults if they don't work.

Doesn't look like there's anything wired into that first mcb

Tony S · Jun 20, 2018

Is the generator centre tapped earth or end tapped?

As RoB said there’s no feed in on the LH MCB, where is the live from the generator?

Other than the above have you carried out any IR testing on the troublesome circuit?

ProDave · Jun 20, 2018

Tony S said:
Is the generator centre tapped earth or end tapped?

As RoB said there’s no feed in on the LH MCB, where is the live from the generator?

Other than the above have you carried out any IR testing on the troublesome circuit?

From latchdogs post above

the feed is coming from the generator, just imagine an active(red) wired into the top of the 63amp main switch, earth(green/yellow) wired into the small earth bar, and a neutral(black) wired into the neutral bar. The house is earthed by an earth stake(earth rod)(running Multiple Earthed Neutral(MEN) earthing system)(Its just a 6mm earth cable from earth bar to neutral bar)

it is completely off the grid, generator is only power source.

So looks like end tapped earth

Tony S · Jun 20, 2018

OK I’ll imagine a live feed, why is the generator struggling when its not connected to the incoming MCB?

Ardet R · Jun 20, 2018

I think ProDave has probably covered it, you need to check the test results of the electricians who installed it (I am sure you have some available!) and see where they have been made up rather than measured.

As an initial check on your installation for the lighting, without the power on check continuity from the top of the 63A MCB to the outgoing line terminals of each RCBO and check you have not got a terminal caught on the core insulation.

For the socket circuit I would tend to do a continuity test (again with the power off) on the outgoing Line and Neutral terminals of the second power circuit to see what current it might be drawing (I=V/R). Then check line neutral continuity for each lighting feed to the first point, as nothing is working on the lights it must be the feeds, but overall I would expect you have had a rogue electrician to install the house wiring, so it will need a lot of checking to ensure safety.

As far as I can tell you have this arrangement at present. Though I am just guessing at the purpose of the circuits)

Lachdog · Jun 21, 2018

Ardet R said:
I think ProDave has probably covered it, you need to check the test results of the electricians who installed it (I am sure you have some available!) and see where they have been made up rather than measured.

As an initial check on your installation for the lighting, without the power on check continuity from the top of the 63A MCB to the outgoing line terminals of each RCBO and check you have not got a terminal caught on the core insulation.

For the socket circuit I would tend to do a continuity test (again with the power off) on the outgoing Line and Neutral terminals of the second power circuit to see what current it might be drawing (I=V/R). Then check line neutral continuity for each lighting feed to the first point, as nothing is working on the lights it must be the feeds, but overall I would expect you have had a rogue electrician to install the house wiring, so it will need a lot of checking to ensure safety.

As far as I can tell you have this arrangement at present. Though I am just guessing at the purpose of the circuits)

View attachment 9454

The drawing is exactly as you have diagramed, but their is also another earth coming from earth stake( in the ground outside the house) to board

No power!!!!

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