Victron Multiplus 12/3000/120 ring main tripping issue?

[KJT]

I have just replaced an 11 year old Victron Multi 12/2000/80 with a new Multiplus 12/3000/120 and have an issue with the ring main CB on the mains consumer unit tripping every time I switch anything on that circuit. The head scratching thing is the CB doesn't trip if I am connected to shore power through the Victron or if I run the diesel genny (3.5kw 230 volt) and switch on the Victron. It seems quite happy running anything up to a 3kw kettle. However, the moment I try and run the inverter from the batteries the ring main CB trips, even with a small load such as a telephone charger! The same is true if I start the engine so the batteries are being charged while the Victron is on. The CB trips immediately any load is switched on when the batteries are supplying the invertor.

The wiring from the battery to the Victron was upgraded to the recommended spec to cope with the increased wattage.

Anyone have any ideas what might be causing the CB to trip?

 

Thanks

 

Ken

[GUMPY]

when you say CB do you mean circuit breaker, detects over current, or RCBO detects earth leakage?

 

ETA my suspicion is that it will be to do with the neutral earth link that is in the new combi when in inverter mode but not in the old one.

Edited June 12, 2013 by Loddon

[Justme]

Do you have the dongle & software?

 

As above I think it will be the N & E link.

[jelunga]

I think you can set the earth link via the dip switches.

[KJT]

Thanks for your prompt and helpful replies.

 

when you say CB do you mean circuit breaker, detects over current, or RCBO detects earth leakage?

ETA my suspicion is that it will be to do with the neutral earth link that is in the new combi when in inverter mode but not in the old one.

 

The CB I refer to is one of several in what is labelled as a 'Kuranda Power Pack' but I think I know it as a consumer unit. The device that keeps tripping is marked as 'Ring main RCD' if that helps.

 

ETA: the RCD has a small window which in the normal ON position shows a red flag and in the tripped position shows a green flag.

 

 

Do you have the dongle & software?

 

As above I think it will be the N & E link.

No I don't have the dongle or software. But I know a man who does! So at least I can point him in the right direction.

 

Thanks again.

 

Ken

Edited June 13, 2013 by NB Ellisiana

[GUMPY]

That it is the RCD confirms that it is to do with the N>E link.

This must be left operational as if disabled the RCD will not work. It but can be disabled to test the theory.

Is the "consumer unit" after or before the inverter i.e. does the unit control the power to the combi or from the combi?

If it is from the combi then I suspect somewhere in your wiring you have a Neutral and Earth swapped or there is an extraneous earth bond.

[nicknorman]

That it is the RCD confirms that it is to do with the N>E link.

This must be left operational as if disabled the RCD will not work. It but can be disabled to test the theory.

Is the "consumer unit" after or before the inverter i.e. does the unit control the power to the combi or from the combi?

If it is from the combi then I suspect somewhere in your wiring you have a Neutral and Earth swapped or there is an extraneous earth bond.

Yes it does suggest a wiring fault, but assuming the previous device didn't have an NE bond and the new one does, that doesn't explain why its fine on shore power but not on inverter. This assumes the Combi is wired normally, to pass through incoming mains, and so the RCD would find incoming shore mains indistinguishable from inverted mains.

[GUMPY]

Yes it does suggest a wiring fault, but assuming the previous device didn't have an NE bond and the new one does, that doesn't explain why its fine on shore power but not on inverter. This assumes the Combi is wired normally, to pass through incoming mains, and so the RCD would find incoming shore mains indistinguishable from inverted mains.

all depends on what protection is on the shore, what is supplying the shore power and where the miswire is, if its not N>E bonded on shore (iso trans O/P) then the fault would not appear.

the N>E link is disconnected when on shore power.

[nicknorman]

all depends on what protection is on the shore, what is supplying the shore power and where the miswire is, if its not N>E bonded on shore (iso trans O/P) then the fault would not appear.

the N>E link is disconnected when on shore power.

Yes that's true, I had presumed a direct incoming L N & E . So maybe 2 faults, a wiring fault but also a failure to NE bond after an IT.

[GUMPY]

Even with LNE coming in if the earth is not connected all the way back to the supply then the RCD will not trip.

I have given this some thought as to how this has been caused and this is where I would check first

 

1; check that the earth is continuous back to the supply on shore

2; check that no sockets are wired N E reversed

3; check that there are no shorts between N & E

 

it will need someone competent to follow this through in a logical manner.

my money is on 1 and 3 as 2 could show up as a non working socket in the boat

 

please let us know what the result is.

[KJT]

Once again, many thanks for your ideas.

 

Is the "consumer unit" after or before the inverter i.e. does the unit control the power to the combi or from the combi?

If it is from the combi then I suspect somewhere in your wiring you have a Neutral and Earth swapped or there is an extraneous earth bond.

The 'consumer unit' is after the invertor. My understanding of the system is that shore power 240v, the diesel genny 230v output and the batteries feed into the Victron and then mains voltage exits from the Victron to the 'consumer unit'. No mains power is available onboard without the Victron being switched on even with output from shore power or genny being available.

 

The system with the 'old' combi unit worked perfectly (apart from a fault on the charging side) and nothing has been changed other than fitting the new unit and increasing the 12v feed wire size to recomended spec to cope with the increased current demand.

 

Thanks again.

 

Ken

Edited June 13, 2013 by NB Ellisiana

[KJT]

Even with LNE coming in if the earth is not connected all the way back to the supply then the RCD will not trip.

I have given this some thought as to how this has been caused and this is where I would check first

1; check that the earth is continuous back to the supply on shore

2; check that no sockets are wired N E reversed

3; check that there are no shorts between N & E

it will need someone competent to follow this through in a logical manner.

my money is on 1 and 3 as 2 could show up as a non working socket in the boat

please let us know what the result is.

I will pass on your thoughts to the engineer that fitted it for me. Hopefully that will resolve the problem.

I am out cruising at the moment but when I return to base in a few days hopefully he can look at it for me then.

 

I will certainly post the outcome.

 

Thanks

 

Ken

[KJT]

The engineer who installed the new Victron returned today to investigate further the issue in the OP.

 

I am pleased to say, thanks in no small measure to the replies on this thread, that the issue has now been resolved.

 

Basically, and I am relaying this as a complete muppet when it comes to electrical issues, this was due to an adverse interaction between a circuit in the Victron (which I believe is not present in the old unit it replaced) and a similar circuit put into the system by Kingsground when the boat was built, tripping the RCD whenever the invertor was supplying the system.

 

As I understand it, it was indeed something to do with the N E link in the system, with one playing off against the other.

 

I am not sure exactly how the fix was accomplished, but everything is OK now.

 

Once again, thanks for your very helpful assistance.

 

Ken

[Biggles]

I have one ring main on mine as yours on the kitchen circuit, The rest are 16 amp spurs.

 

I have had it wired from the start exactly how the inverter came. I have never reset the N&E setting.

 

Never had a problem with tripping unless it needed to when I've done something stupid like cutting through a live wire

[by'eck]

That it is the RCD confirms that it is to do with the N>E link.

This must be left operational as if disabled the RCD will not work. It but can be disabled to test the theory.

Is the "consumer unit" after or before the inverter i.e. does the unit control the power to the combi or from the combi?

If it is from the combi then I suspect somewhere in your wiring you have a Neutral and Earth swapped or there is an extraneous earth bond.

 

Its a common misconception that the RCD will not work without a N/E bond. Since it works by detecting any minute imbalance in the current flowing through live and neutral legs, there is absolutely no reason to assume it won't work without a N/E bond.

 

However, and most importantly, it will not provide the safety protection its designed for unless a N/E bond is present since without it will have no reference. Without the bond a person within the boat brought into contact with the live leg would not necessarily trip the RCD if no imbalance occurred. Any leakage would not be detected either.

[nicknorman]

Its a common misconception that the RCD will not work without a N/E bond. Since it works by detecting any minute imbalance in the current flowing through live and neutral legs, there is absolutely no reason to assume it won't work without a N/E bond.

 

However, and most importantly, it will not provide the safety protection its designed for unless a N/E bond is present since without it will have no reference. Without the bond a person within the boat brought into contact with the live leg would not necessarily trip the RCD if no imbalance occurred. Any leakage would not be detected either.

But they wouldn't get a shock either. If earth is not connected to one or other of L or N, touching L or N not only doesn't trip the RCD, it also doesn't hurt!

[by'eck]

But they wouldn't get a shock either. If earth is not connected to one or other of L or N, touching L or N not only doesn't trip the RCD, it also doesn't hurt!

 

In a perfect world true, but you have an unpredictable situation without N/E bond due to inverter live and neutral effectively floating with lack of reference.

[nicknorman]

If they did get a shock, either the L N balance would be upset (RCD trips even without NE bond) or, if they were connected to both L and N, the RCD wouldn't trip regardless of N E bond (LN current remains balanced)

[by'eck]

If they did get a shock, either the L N balance would be upset (RCD trips even without NE bond) or, if they were connected to both L and N, the RCD wouldn't trip regardless of N E bond (LN current remains balanced)

 

Not true - if a person were connected to live and neutral with N/E bond, some of the current flowing through their body would be via boat hull hence creating imbalance and trip.

[nicknorman]

Not true - if a person were connected to live and neutral with N/E bond, some of the current flowing through their body would be via boat hull hence creating imbalance and trip.

Not necessarily, eg wearing rubber soled shoes standing on lino and not touching anything else.