Earth Leakage question ?

[bitbaltic]

As the sockets seem to be the problem, there’s nothing to be lost by isolating everything then withdrawing every faceplate and having a look at the wiring behind them. In my experience (of making good botched domestic installations) the sockets are where people with sketchy knowledge are most likely to have done some sort of botch job which causes poor connections or wires burning out. Can’t hurt to check the condition of all that while you wait for an opinion on the inverter.

 

[VicS]

Here is the schematic - Id like to understand how the RCD is connected and suggestions as to why it doesn’t trip using the Inverter - as you can see the diagram shows the same RCD in both supply options

Thanks a lot for your guidance

Refer to the inverter installation manual and check that the link labelled "Inverter grounding " in the schematic is in fact fitted
Check the continuity of the connection between the inverter PE terminal and the main PE bus bar.

The output from the inverter does not go through the main RCD so an earth leakage will not trip that when the system is powered from the inverter. The inverter has its own RCD, which should trip.
It should be possible to check the functionality of this in a similar way to the way you check the main RCD. Refer to the inverter operating instructions.

 

[PaulRainbow]

Here is the schematic - Id like to understand how the RCD is connected and suggestions as to why it doesn’t trip using the Inverter - as you can see the diagram shows the same RCD in both supply options

Thanks a lot for your guidance

According to the schematic:

Shore power is connected to the double pole isolator(13) ( and the RCD (17), from there it goes to all of the loads except the microwave and sockets. With the exception of the microwave and sockets, everything else will only work from shore power and will be protected by the RCD (earth leakage). Shore power is also connected to the transfer switch (23), as is the inverter, via a second RCD.

If shore power is selected the microwave and socket power passes through the RCD (17) which will trip in the event of an earth leak. If the inverter is selected the inverter RCD (17a) provides protection.

As 17a does not trip it's likely that it's either faulty or the earth connection from the inverter isn't connected correctly. You need to check for continuity between the inverter earth and the water to ensure a good earth connection is present, assuming the RCD tests as ok.

 

[PaulRainbow]

Refer to the inverter installation manual and check that the link labelled "Inverter grounding " in the schematic is in fact fitted

This is factory fitted with a Mastervolt inverter.

Check the continuity of the connection between the inverter PE terminal and the main PE bus bar.

That's not sufficient, he needs to check for a proper earth connection, to water. The could be continuity to the busbar and from there to the shore power connection, which would allow for the shore power RCD to trip, but there could be a break between the busbar and the water, which will disable the inverter RCD and the protection it should provide.

The output from the inverter does not go through the main RCD so an earth leakage will not trip that when the system is powered from the inverter. The inverter has its own RCD, which should trip.
It should be possible to check the functionality of this in a similar way to the way you check the main RCD. Refer to the inverter operating instructions.

 

[Boater Sam]

Its definitely not the water heater which has its own circuit breaker and turns on no problem - its definitely one of the 240v sockets or wiring

If the element has a neutral to earth leakage it will still work without tripping the excess current circuit breaker but will trip an rcd.

That is exactly what mine does when it has not been used for a long period.

 

[Boater Sam]

The water heater is only connected to the shore line supply, it is not connected in any way to the inverter supply. There is a clue there.

 

[Delfini]

According to the schematic:

Shore power is connected to the double pole isolator(13) ( and the RCD (17), from there it goes to all of the loads except the microwave and sockets. With the exception of the microwave and sockets, everything else will only work from shore power and will be protected by the RCD (earth leakage). Shore power is also connected to the transfer switch (23), as is the inverter, via a second RCD.

If shore power is selected the microwave and socket power passes through the RCD (17) which will trip in the event of an earth leak. If the inverter is selected the inverter RCD (17a) provides protection.

As 17a does not trip it's likely that it's either faulty or the earth connection from the inverter isn't connected correctly. You need to check for continuity between the inverter earth and the water to ensure a good earth connection is present, assuming the RCD tests as ok.

Thanks for that - can you just explain why you believe there are 2 x RCD’s - as far as I can tell the RCD contacts for both shore power and inverter (as shown in the drawing) refer to the same RCD and marked 17 (A) - I am only aware of 1 x physical RCD on the main switch panel - perhaps its a double (4 pole) device ?

 

[TernVI]

Here is the schematic - Id like to understand how the RCD is connected and suggestions as to why it doesn’t trip using the Inverter - as you can see the diagram shows the same RCD in both supply options

Thanks a lot for your guidance

There are TWO RCDs in the diagram.
one controls the shore power
one controls the inverter power.

If the inverter one never pops, it suggests that the loads powered by the inverter via the transfer swtich are not faulty.

How old is the boat and how sure are you that the boat still conforms to the diagram?

 

[TernVI]

The table in bottom right is an items list, it says number 17, RCD, two of.

 

[Boater Sam]

The water heater element does not power from the inverter so the rcd does not trip. It does power from the shore line which trips the shore line rcd.
There is an obvious conclusion.

Disconnect the water heater completely, line and neutral, and see what happens.

 

[Delfini]

The reason the inverter does not trip the RCD would appear to be that the output of the inverter is quite simply not connected to the RCD.
The RCD protects the shore power only.
The inverter output goes to the transfer switch and directly off to the loads it feeds.
The inverter may have its own internal protection, but how that might work with the 'neutral' 'earthed' I'm not prepered to speculate as I haven't read the manual for the inverter. It would make more sense to me with the 'neutral' floating like a site transformer.....

Personally I would consider fitting a second RCCB between the 'inverter earthing point' and the transfer switch.

... perhaps you didn’t see the schematic - it shows a pair of RCD contacts (17 A) protecting the Inverter output - Ive just got a) to find it and b) figure out and why its not working and then c) fix my earth leakage problem ?

 

[Delfini]

The table in bottom right is an items list, it says number 17, RCD, two of.

Thanks - I missed that - I wonder what the” A” ref means in the diagram - could it be suggesting there are 2 x RCD’s in 1 package with 1 x master reset for both - I haven’t found any other RCD devices other than that on the main panel and surely it should be accessible/obvious so it could be reset if tripped ?

 

[TernVI]

... perhaps you didn’t see the schematic - it shows a pair of RCD contacts (17 A) protecting the Inverter output - Ive just got a) to find it and b) figure out and why its not working and then c) fix my earth leakage problem ?

Yes, sorry I initially misread the diagram and have edited my post, like deleted it and started again. Please delete your quote of my post as it's not going to help.
I suspect if you can't find it, your installation has been changed? It should be close to the inverter, there come a time when I'd just follow the wires from inverter to transfer switch.

It is possible someone has upgraded the inverter to one with internal protection?

But if the diagram is still at all relevant, then the leakage problem is probably a separate issue from understanding the inverter.

 

[TernVI]

Thanks - I missed that - I wonder what the” A” ref means in the diagram - could it be suggesting there are 2 x RCD’s in 1 package with 1 x master reset for both - I haven’t found any other RCD devices other than that on the main panel and surely it should be accessible/obvious so it could be reset if tripped ?

In my experience of parts lists and so forth, that is unlikely, it gives a manufacturer and part number and say get two of these.
But can you not see how many wires go in and out?

Is the inverter the orignal? make and part number? Wattage?

 

[TernVI]

Searching for the part number of the inverter gives a common or garden 2 pole device:
https://docs.rs-online.com/62f5/0900766b802d2cfe.pdf

 

[Delfini]

Thanks - I missed that - I wonder what the” A” ref means in the diagram - could it be suggesting there are 2 x RCD’s in 1 package with 1 x master reset for both - I haven’t found any other RCD devices other than that on the main panel and surely it should be accessible/obvious so it could be reset if tripped ?

It looks like the ref “A” is document change control - ref “A” top right translates from Swedish into "added / moved error power switch” - seems they added/moved the RCD’s in March 1996 - I still don’t know if I need to be looking for a second physical RCD or if its already on the panel - I will take a look when Im next down the boat?

 

[Delfini]

Searching for the part number of the inverter gives a common or garden 2 pole device:
https://docs.rs-online.com/62f5/0900766b802d2cfe.pdf

Great - thats the one on the panel - so it seems Im looking for another RCD somewhere - thanks very much to all - most helpful

 

[PaulRainbow]

The water heater element does not power from the inverter so the rcd does not trip. It does power from the shore line which trips the shore line rcd.
There is an obvious conclusion.

Disconnect the water heater completely, line and neutral, and see what happens.

Stop banging on about the water heater, it isn't helping. The OP has already said, more than once, that if he turns the sockets off the RCD does not trip and the water heater etc all work fine.

 

[PaulRainbow]

It looks like the ref “A” is document change control - ref “A” top right translates from Swedish into "added / moved error power switch” - seems they added/moved the RCD’s in March 1996 - I still don’t know if I need to be looking for a second physical RCD or if its already on the panel - I will take a look when Im next down the boat?

Follow the wiring from the inverter to the transfer switch, the RCD should be between the two.

When you change the transfer switch to "inverter" there should be an RCD in that supply, close to the inverter.

 

[BabaYaga]

It looks like the ref “A” is document change control - ref “A” top right translates from Swedish into "added / moved error power switch”

Felströmsbrytare (Fenno-Swedish) = Jordfelsbrytare (Swedish) = RCD (English)

 

[starfire]

Follow the wiring from the inverter to the transfer switch, the RCD should be between the two.

When you change the transfer switch to "inverter" there should be an RCD in that supply, close to the inverter.

Could be part of the inverter ?