Earthing sockets in Bulgaria

[bulgariasteve]

I am about to install new wiring for a kitchen here in Bulgaria. I will be using a 2.5 ring final circuit for the sockets and 6 mm radial for the cooker. Wiring to sockets here in Bulgaria is done by using twin cable (no earth line). The earthing is done by connecting the earth and neutral point together on each socket. In effect this becomes a TN-CS system of earthing. My question is would it be better to use twin and earth cable and connect the earth to the neutral block at the consumer unit?
Cheers, Steve

 

[Lucien Nunes]

I am not sure the ring final is recognised in Bulgaria. You would have to fuse it at 16A in the CU in order to protect the sockets, so what's the point? Why not 16A radials?

Providing an earth at a socket using the neutral is TN-C, not TN-C-S. I.e. the neutral and earth are Combined all the way to the end of the circuit, rather than Combined for part of the way and then Separate.

Because of the likelihood of exposed metalwork becoming live in the event of the combined neutral-earth conductor being broken, the fewer joints there are in it, the better. I would be much happier running a separate earth conductor back to the CU, which makes it almost a standard TN-C-S system.

E2A, I see the value of a ring, or at least a duplicated CNE conductor, on a TN-C system! But, better to not to have a CNE in the final at all. What do the regs say?

 

[Pete999]

I am not sure the ring final is recognised in Bulgaria. You would have to fuse it at 16A in the CU in order to protect the sockets, so what's the point? Why not 16A radials?

Providing an earth at a socket using the neutral is TN-C, not TN-C-S. I.e. the neutral and earth are Combined all the way to the end of the circuit, rather than Combined for part of the way and then Separate.

Because of the likelihood of exposed metalwork becoming live in the event of the combined neutral-earth conductor being broken, the fewer joints there are in it, the better. I would be much happier running a separate earth conductor back to the CU, which makes it almost a standard TN-C-S system.

E2A, I see the value of a ring, or at least a duplicated CNE conductor, on a TN-C system! But, better to not to have a CNE in the final at all. What do the regs say?

The local Regs Ishould think are the ones you are referring to, I hope

 

[Cookie]

This was typical in the USSR and the practice was brought over to satellite countries.

By all means run new twin and earth if you can. I wouldn't even think twice converting a TN-C system to TN-C-S. A separate earth back to the consumer unit is also good.

A ring is a bad idea as schuko plugs are not fused.

 

[bulgariasteve]

Thanks Lucien, Pete and Cookie for your helpful posts. I am leaning now towards putting in 2 radials 2.5 twin and earth each with a 20 amp mcb thus splitting the kitchen load. This would avoid the potential problem of a ring not meeting Bulgarian standards.I have thought about using a single 4mm radial, but as the sockets available here are so flimsy and the connection points quite small, would make it difficult! Do comment further if you think of a better option. I am attaching 2 pictures of the work from a qualified Bulgarian electrician. He joined onto an existing 2.5 radial with the intension of conecting an 8kw cooker plus sockets. On the same circuit he had already attached a 3kw water heater!! Note the nails used to pin the cable to the wall!! Cheers, Steve

 

[Lucien Nunes]

Please check the local regs as to the maximum permitted MCB size. It might be 16A as it protects the appliance flexes too, unlike the UK where the plug fuse is responsible for that.

In the UK we used to have Maconite cable that was fixed by nailing through a web in the middle. In Europe there is NYIF-J, popular in German derived installation practice aka 'Stegleitung' etc. The Bulgarian guy is just using the same method with whatever cable he can get!

 

[Cookie]

2.5mm2 radial at 20amps will do. Avoid doing a ring.

 

[bulgariasteve]

Thanks Cookie and Lucien. I have spoken to a good Bulgaria electrician and I am assured that using 20 amp mcb's is normal practise here. Cheers guys, Steve

 

[Cookie]

20 amp MCBs and schuko sockets is normal practice in many parts of Europe (like France for example), and 20amp 120 volt circuits are mandated in US Kitchens and Laundry rooms. So IMO there is no risk using a 20amp MCB.


BTW, don't nail through the wire. That is not a good idea.

 

[bulgariasteve]

Thanks Cookie. Will avoid nailing!!