Neutral and earth bonded together

[Igor Taranenko]

Hi All, apologies for a long post I'm currently in my in-laws house abroad and while having some break I also fixing electrical issues as it seems to be quite few.

It's a farm estate and wiring quite old with some DIY involvement over the years in Ideal world I would rewire whole thing but it would take probably couple of months. So my main focus is to sort issues with basic protection such damaged accessories, lights fitting, IP rated sockets & switches where needed, instaling new sockets to get rid of extension leads and etc. Sockets in the house does not have earth. It concerns me especially considering washing machine and boiler in bathroom facility and oven with fridges in the kitchen. My plan is to fit local RCDs for bathroom & kitchen sockets and I want to earth sockets in the bathroom and kitchen but not sure where I'm going to connect the other end. It looks like there is earth connection at the fuseboard with the rod going into the ground but I found that this earth and incoming neutral are bounded together (See picture). It's a 3 phase and neutral coming in, only one phase used. Owner told me that it was since they moved 16 years ago.
I was thinking to connect earth for bathroom & kitchen sockets to the same main earth terminal considering its grounded via rod but the fact that it is also bounded with neutral makes me wander. Or shall I stick another rod for my earthing and not to worry about effectiveness of existing rod and potential earth path? I know electrical condition is a bit mess here but all I want is to make it a little safer while I'm here. I'll be happy for any advice or similar experience and what you do giving this circumstance.
Many thanks

 

[James]

What is the wiring system?

Could it be singles in metal conduit?

I would not be adding a second earth and keeping it separate from existing earth, if I read your post correctly , how will you prevent different voltages being present on the two systems.

First things first, screw sockets back on and do an earth loop test to see if there is actually an existing connection

 

[Pete999]

What is the wiring system?

Could it be singles in metal conduit?

I would not be adding a second earth and keeping it separate from existing earth, if I read your post correctly , how will you prevent different voltages being present on the two systems.

First things first, screw sockets back on and do an earth loop test to see if there is actually an existing connection

Where are your relatives based? I only ask cus that switchgear reminds me of the Russian stuff I worked on when I was posted to Moscow, looks a bit rough as well.

 

[pc1966]

The country flag is saying Latvia.

In a post some months ago @Lucien Nunes pointed out a lot of former Soviet countries often have 3-phase TN-C supplies with fairly low per-phase current limit, so you could be in for a confusing time looking at that.

It would be worth checking out any local regulations, but personally I would look to make it a TT system after checking that the earth rod(s) are safe & sound. However, you would be looking at a rewire almost certainly in case one or more final circuits are wired TN-C as well.

UK regs don't permit RCD on TN-C as that would disconnected the CPC as well. I guess the concern is any other source of current being present?

Just my 2p of thoughts...

 

[Igor Taranenko]

Where are your relatives based? I only ask cus that switchgear reminds me of the Russian stuff I worked on when I was posted to Moscow, looks a bit rough as well.

It is in Latvia, rural area. There is a label dated at 1988, made in USSR! Yes, it does look dodgy, neighbours telling me their electrics looks even worse) most work in rurals are done by DIYers. Mentality here "give me the phase and I'll do the rest"!

 

[Pete999]

Russian Electrics and Regulations don't make me laugh.

 

[pc1966]

Is there a dedicated supply transformer for that property? You might find the earth is the only one for that supply!

Looking at your picture has a number of other issues raised: For a start, is the (apparently bypassed) main incomer switch actually a RCD? Also what is the 36V supply (apparently with fuse removed) intended for?

How long are you there for and what sort of a budget do you have for any remedial work? I suspect you did not pack your tools on that trip as I don't think you had such work planned!

I have long wanted to visit the Baltic states but sadly never found the time so far My pi**-poor grasp of anything other than English would not help, mind you!

 

[Igor Taranenko]

Is there a dedicated supply transformer for that property? You might find the earth is the only one for that supply!

Looking at your picture has a number of other issues raised: For a start, is the (apparently bypassed) main incomer switch actually a RCD? Also what is the 36V supply (apparently with fuse removed) intended for?

How long are you there for and what sort of a budget do you have for any remedial work? I suspect you did not pack your tools on that trip as I don't think you had such work planned!

I have long wanted to visit the Baltic states but sadly never found the time so far My pi**-poor grasp of anything other than English would not help, mind you!

I'm here for another 4 days and don't really have much time for complex work, only small remedials. And I don't have my multimeter here, only basic one which I purchased here to help me with Voltage & resistance check for small jobs.

Yes, the main switch not in use and to be fair not sure if this is a old type RCD or not.

Relative will show meter box tomorrow so I might find something interesting too.
[automerge]1595615766[/automerge]

What is the wiring system?

Could it be singles in metal conduit?

I would not be adding a second earth and keeping it separate from existing earth, if I read your post correctly , how will you prevent different voltages being present on the two systems.

First things first, screw sockets back on and do an earth loop test to see if there is actually an existing connection

It's hard to say in regards to wiring. No metal conduit but I've noticed singles in in few places there looks like it's been originally installed. Two cores were added on later for extra socket and new lights.

Unfortunately I don't have my MFT to do loop empedance.

 

[pc1966]

Sounds like you could do with a 2nd planned visit for a couple of weeks to sort it out properly! Good luck with what you can manage to do just now.

 

[Igor Taranenko]

Sounds like you could do with a 2nd planned visit for a couple of weeks to sort it out properly! Good luck with what you can manage to do just now.

Thanks, I'm pretty sure there will be more work for me)

 

[Lucien Nunes]

Yes, it looks like 3-phase TN-C to the panel, with only one phase (green = L2 or B-phase) in use. So the main feed to the breakers is that little white wire (white = line) probably 4mm², and the neutral is that other muddy looking wire to the stud on the left side of the box, where it meets the CNE from the supply cable and the other single cable which is presumably to the rod.

If none of the outgoing circuits have any CPC or N-E links, then an RCD could be fitted in these two conductors, and any new wiring with CPC that you connect would need its CPC separately connected to that stud. It needs to be a rock-solid connection as it's a CNE. Spare no effort! Posher DB's had a terminal bar with separate terminals for N & CPC.

The 220-36V stepdown transformer is the black object bottom right. This was a standard Soviet arrangement for powering lights in garages, cellars etc where PELV was desired on grounds of likely humidity etc. Presumably whatever points it served have been converted to 220V as the secondary fuse is removed, although the primary fuse still appears to be present.

 

[Igor Taranenko]

Yes, it looks like 3-phase TN-C to the panel, with only one phase (green = L2 or B-phase) in use. So the main feed to the breakers is that little white wire (white = line) probably 4mm², and the neutral is that other muddy looking wire to the stud on the left side of the box, where it meets the CNE from the supply cable and the other single cable which is presumably to the rod.

If none of the outgoing circuits have any CPC or N-E links, then an RCD could be fitted in these two conductors, and any new wiring with CPC that you connect would need its CPC separately connected to that stud. It needs to be a rock-solid connection as it's a CNE. Spare no effort! Posher DB's had a terminal bar with separate terminals for N & CPC.

The 220-36V stepdown transformer is the black object bottom right. This was a standard Soviet arrangement for powering lights in garages, cellars etc where PELV was desired on grounds of likely humidity etc. Presumably whatever points it served have been converted to 220V as the secondary fuse is removed, although the primary fuse still appears to be present.

Thanks for useful information, really helpful. As I understand it's best not to install additional rod for earth conductors I've created for sockets in bathroom & kitchen but to connect it directly to that stud in fuseboard.

 

[pc1966]

Thanks for useful information, really helpful. As I understand it's best not to install additional rod for earth conductors I've created for sockets in bathroom & kitchen but to connect it directly to that stud in fuseboard.

I would always bring them back to the board to make all CPC part of the one systems.

If you suspect the current rod is not very good then adding additional rods in parallel can be the easiest option, possibly with a separate earth wire to the board if the current earth wire is suspect. Then all circuits benefit from the lower total Ra value.