1
\$\begingroup\$

Where is/are the correct place(s) where PE (ground) and N (neutral) should be connected in a 230 V TN-C-S network? One or multiple times?

In the fusebox of my rental apartment (several apartments per house), the thick "inward" cable contains yellow-green (PE, ground), blue (neutral), black, brown (and possibly gray, hard to see because it is very tight, phases L1-3).

Within the fusebox, the metal bars with all the subsidiary wires for (a) blue and (b) yellow-green going to kitchen, bedroom etc. are connected by a thick short yellow-green wire, essentially creating an (additional?!) connection between N and PE, or - on other words - render the PE and N "before" my apartment a common (double) PEN wire.

I believe I had learned that the "outdoor" TN-C with "connected" PE-N should be separated to TN-S (with separated PE and N) at the place where earthing is placed (there is obviously no direct earthing for PE in my flat), usually at the mains entry to the whole house and the main brakers (cannot find original description, but in line with the answer of this post). The incoming already separated blue and yellow-green suggest they have in fact been separated before.

=> is it correct (allowed, or maybe even necessary?) to have such additional connections between N and PE?

Edit: I re-checked, it turns out that we have different "shades of blue" (which I deem not very intelligent): big wires from house to my fusebox: yellow-green is PEN (not PE), and 3 phases are black, brown and blue (live! - very old convention). Smaller wired from fusebox to sockets etc.: PE, N (blue! - new convention!), and phases (only black is used). => PEN is separated into P and NE in my fusebox, i.e. distant from central earthing point. Is this ok?

Schematic drawing: enter image description here

Photo of equipotential bonding busbar and wires (purple circle in drawing above). What are the 4 wires plus solid metal bar ging downwards? enter image description here

\$\endgroup\$

1 Answer 1

0
\$\begingroup\$

Where is/are the correct place(s) where PE (ground) and N (neutral) should be connected in a 230 V TN-C-S network? One or multiple times?

Only one single point. After that PE and N have to be separated all the way.

is it correct (allowed, or maybe even necessary?) to have such additional connections between N and PE?

No at all.

\$\endgroup\$
4
  • \$\begingroup\$ Thanks! This would help me a lot as answer if you could add a short note WHERE the PE/N separartion may/should occur, also regarding the (distance to) the earthing point. (situation became more complex, see edit, but does not matter for the question of where). \$\endgroup\$
    – Martin
    Commented Sep 8, 2019 at 22:24
  • \$\begingroup\$ Anywhere, regardless of the distance. You should edit your question and add a circuit drawing ( it's just drawing lines in your case), I get lost while reading your description. \$\endgroup\$ Commented Sep 9, 2019 at 6:31
  • \$\begingroup\$ Added drawing as requested. If you say, the distance (and thus the amount of TN-C within house) does not matter, this would be the answer. Bonus Q: what are the 4 big wires plus the solid metal bar, going downwards from the equipotential bonding busbar to the floor (purple circle and photo)? Big one for earther, I guess. Others - to iron water pipes, additional earthers...? \$\endgroup\$
    – Martin
    Commented Sep 9, 2019 at 21:27
  • \$\begingroup\$ Hi, nice presentation since last viewed. The wires connected to bussbar are earthing as you have already found out: water pipes, foundation earthing, ground rods,...It's done very good indeed, nothing differently compared to the distribution from street cabinet to housing, except there are other series connected flats. So the PEN comes from street cabinet->main house -> flats. Each house the PEN is then separated in PE and N, so never reconnected back again. \$\endgroup\$ Commented Sep 19, 2019 at 11:55

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.