Neutral connected to earth in wall socket. OK? Legal?

[RGB255_0_0]

If the pole in your street falls over and the engineer connects L/N the wrong way your PE is live. 

Wouldn't that happen anyway with TN-x system regardless?

[rob77]

If the pole in your street falls over and the engineer connects L/N the wrong way your PE is live. 

sorry that's bullshit... how the hell could a technician swap one of the phases with the PEN wire at the pole ? and even if he somehow miraculously did... how could the PEN wire become live ? the PEN wire is grounded with a ground plate dug into earth at the input to the house/building. so swapping a phase wire with PEN at the utility pole would cause HUGE fault current flowing to ground and bring the whole thing down.

the input to house or building is ALWAYS a common wire for both neutral and ground marked  PEN, then the PEN wire is split up to separate PE and N wire in the distribution box... and from there it's 3wire wiring with L + N + PE wires and it's forbidden to connect N and PE again after this point of separation in the distribution box.
in the past a 2 wire system was used - where you had only 2 wires to outlets: phase and PEN and the PEN wire was connected to both neutral and ground of the outlet.
the 2 wire is system is not dangerous and is completely legal - no-one needs to replace the wiring in the older houses. however for every new installation or rebuild the 3 wire is mandatory and RCD/GFCI is mandatory for every outlet used by ordinary persons (RCD/GFCI don't work with 2wire installation).

[helius]

It is even possible that the house was built before electricity. You know, Europe is old. Sometimes I wish, we would just demolish all buildings every 30 years, like the US. But then again, I take a walk, and citys are breathtaking and beautiful, instead of brutalist concrete jungle.

I'm not sure where these perceptions come from? The median age of buildings in the US is over 40 years, so there are equal numbers built since 1975 as those standing from before 1975. In Boston and New York, 19th century buildings (before electricity) are common, up to 20% according to census data.
If anything, I would expect the structures in older US cities to have greater median age because they were never carpet bombed.

[station240]

The risk is that should the bond between the earth and neutral break at the switchboard end (wire disconnects, earth stake loose). Then the metal case of every appliance can float high.

[Zero999]

Neutral and earth are the same thing. The neutral will be connected to the earth, where it enters the building, and is earthed at multiple points. It's known as a TN-C network.

Not in this case, though.

Yes it is a TN-C network. The neutral and protective earth share a conductor, right up to the wall socket, where they split and become separate conductors in the mains plug and device's cable.

because of:

The neutral will be connected to the earth, where it enters the building

I think what you're referring to is a TN-C-S network, where the neutral & earth are only shared between the distribution transformer and the property's distribution board.

TN-C-S earthing system: combined PEN conductor from transformer to building distribution point, but separate PE and N conductors in fixed indoor wiring and flexible power cords.

https://en.wikipedia.org/wiki/Earthing_system#TN_networks

Not safe and not legal. Earth and neutral can be connected together but not at the socket as it is outright dangerous may any wiring fault occur. If neutral wire gets disconnected anywhere, the enclosure of the device will be at live voltage.

The same can happen with a TN-C-S network (separate protective earth and neutral conductors in the building's wiring), if there's already a high leakage current between phase and earth and a break occurs in the protective earth conductor. Fortunately on modern installations the RCD will trip due to the high leakage current so the second fault isn't dangerous, as the power will already be interrupted.

As far as legality is concerned: as many other people have pointed out, a TN-C network (shared neutral and protective earth inside the building wiring) legal for old wiring in some jurisdictions but new wiring has to have a separate PE conductor.

[Jeroen3]

If the pole in your street falls over and the engineer connects L/N the wrong way your PE is live. 

sorry that's bullshit... how the hell could a technician swap one of the phases with the PEN wire at the pole ? and even if he somehow miraculously did... how could the PEN wire become live ? the PEN wire is grounded with a ground plate dug into earth at the input to the house/building. so swapping a phase wire with PEN at the utility pole would cause HUGE fault current flowing to ground and bring the whole thing down.

They do make this mistake sometimes. It causes major damage with three phase systems. They even manage to perform this trick on entire streets every few years.
And if I swap L/N in my junction box I have no issue. N is not connected to PE at my house. It is at the transformer building.
Not sure, but Austria uses similar setup iirc. Only with poles due to terrain difficulties.

[tszaboo]

It is even possible that the house was built before electricity. You know, Europe is old. Sometimes I wish, we would just demolish all buildings every 30 years, like the US. But then again, I take a walk, and citys are breathtaking and beautiful, instead of brutalist concrete jungle.

I'm not sure where these perceptions come from? The median age of buildings in the US is over 40 years, so there are equal numbers built since 1975 as those standing from before 1975. In Boston and New York, 19th century buildings (before electricity) are common, up to 20% according to census data.
If anything, I would expect the structures in older US cities to have greater median age because they were never carpet bombed.

15% of germany  (was carpet bombed) is over 100 years old, and another 60% is built before 1970. You can bring up New york, as an example, but it is going to be the exception.
http://eyeonhousing.org/2012/08/the-geography-of-the-age-of-the-housing-stock/
I'm not going to do a search for the date, from which earthing is necessary. I believe it to be in the 70-80s.

[rob77]

N is not connected to PE at my house. It is at the transformer building.

do you have 5 wire distribution network then ?  in Europe usually the network is 4 wires: 3 x L + PEN , the PEN is the separated into PE + N in the house/building and in addition the PE is grounded with a ground plate dug into ground.

[Zero999]

If the pole in your street falls over and the engineer connects L/N the wrong way your PE is live. 

That would be impossible in locations where all cables after the distribution transformer are buried underground, which is often the case in urban locations. Quite often buried cables consist of a tube which is earth/neutral with no insulation and the phase conductors in the middle.

the input to house or building is ALWAYS a common wire for both neutral and ground marked  PEN, then the PEN wire is split up to separate PE and N wire in the distribution box... and from there it's 3wire wiring with L + N + PE wires and it's forbidden to connect N and PE again after this point of separation in the distribution box.
in the past a 2 wire system was used - where you had only 2 wires to outlets: phase and PEN and the PEN wire was connected to both neutral and ground of the outlet

That's a bit of a generalisation. There are other possibilities, such as having a separate neutral and earth from the transformer to the property (TN-S) or no earth between the property and distribution transformer and connecting the earth conductor to a buried electrode (TT).
https://en.wikipedia.org/wiki/Earthing_system

[Jeroen3]

N is not connected to PE at my house. It is at the transformer building.

do you have 5 wire distribution network then ?  in Europe usually the network is 4 wires: 3 x L + PEN , the PEN is the separated into PE + N in the house/building and in addition the PE is grounded with a ground plate dug into ground.

Phase and Neutral 40 Amps. With earth rod. But only wired to bathroom, kitchen, central gas heating and garage.

[Kevin.D]

If the pole in your street falls over and the engineer connects L/N the wrong way your PE is live. 

sorry that's bullshit... how the hell could a technician swap one of the phases with the PEN wire at the pole ? and even if he somehow miraculously did... how could the PEN wire become live ? the PEN wire is grounded with a ground plate dug into earth at the input to the house/building. so swapping a phase wire with PEN at the utility pole would cause HUGE fault current flowing to ground and bring the whole thing down.

I think it must be different where you are then since here  In a  TN-C-S system it is not required to have separate plate or rod buried to earth at property  since the earth is being provided by the feeder Neutral (which is earthed at multiple points by the supplier but not necessarily at each property). My house used to be  TT (Tera-Tera) system which must provide it's own earthing point using a buried rod/plate at each property. It's was converted to TN-C-S some years ago at last rewire, one of the benefits of this system is that individual properties no longer need to maintain/have there own earth rods/plates.
So this means a mix up of phase(L)/pen(N) to an individual property could happen at the suppliers entry box. I actually bought this up a few months a ago with someone who was then discussing the various reasons why anyone should never  use/trust a neon screwdriver as an indicator of safety but always use and trust his meter instead. I agreed and then I thought of this scenario (L-PEN swapped at property service head) as one scenario that would actually result in your meter giving a false safe reading but a neon still would indicate live.
 It's unlikely yet still possible :- if this happens on a property that was fed by plastic water/gas pipes (so therefore no other earthed point's in the property) and main breaker (double pole) is off then all neutral/earthed metal work inside property would now be live via the PE connection to N  service head (which bypasses main breaker). But since there is now no neutral/earths present (o/c with main breaker off) within property wiring then measuring anywhere after main breaker between L-N,L-E, E-N would show nothing on a Voltmeter. A neon though which only need capacitive coupling to earth would still indicate N,E are live.

Regards.

[janoc]

It's illegal and doesn't meet wiring standards unless you live in a so called third world country where nobody give a shit. What if your house or flat burnt down or you were killed because of a neutral fault putting AC onto the neutral, in your case earth, your insurance company wouldnt pay out a penny.

Mate, I dare you to get out of your living room and actually check some old installations around you in the UK. You will be likely *very surprised* what you will find.

Then, once you have all that fixed, you can call other places "third world countries" 

[Ian.M]

Its *extremely* rare to see anything like that in the UK. Since the introduction of the BS1363 plug/socket system in 1947, an Earth connection to each BS1363 socket has been mandatory and the pre-BS1363 sockets were round pin, so visually distinct, and usually had to be replaced to make a property saleable.  Its often a condition of buildings insurance that an electrical inspection has been performed within a certain number of years and any issues found remediated and DIY work now requires inspection so you typically only see the like when a resident since WWII or shortly thereafter who hasn't had significant electrical work done since the '60s dies or is taken into care.   

[G7PSK]

The earth and neutral are very often one wire up until they reach the meter cabinet especially in rural areas, two wires to the house with the neutral earthed at the transformer and the house.

[janoc]

Its *extremely* rare to see anything like that in the UK. Since the introduction of the BS1363 plug/socket system in 1947, an Earth connection to each BS1363 socket has been mandatory and the pre-BS1363 sockets were round pin, so visually distinct, and usually had to be replaced to make a property saleable.  Its often a condition of buildings insurance that an electrical inspection has been performed within a certain number of years and any issues found remediated and DIY work now requires inspection so you typically only see the like when a resident since WWII or shortly thereafter who hasn't had significant electrical work done since the '60s dies or is taken into care.

Well, consider yourself lucky then - most of the continent doesn't allow such installations anymore, but unless the building is being renovated/major work is being done, there is usually no obligation to replace the wiring (= enormous expense)

E.g. in Denmark where I lived or here in France it is very common - in my current apartment which is in a fairly recent block of flats (perhaps 15-20 years old max.) I have several outlets that have only two pins (no ground) and are not even recessed - similar to the US-style outlets, only with round holes, so if you aren't careful, you could get shocked while inserting/removing the plug. In Denmark you will commonly find round outlets (like the French or German Schuko style) but with no earthing prong nor contact - only two pins for live and neutral.

Two wire/no ground wiring is still fairly safe for normal indoor installations (unless some retard connected the neutral and grounding pins in the outlet!) where most of the appliances are doubly insulated anyway. The only exceptions are typically large appliances like water heaters, ovens, washing machines, etc. - there it was common to require separate grounding for them.

[SteveyG]

The earth and neutral are very often one wire up until they reach the meter cabinet especially in rural areas, two wires to the house with the neutral earthed at the transformer and the house.

Normally the opposite. TT is usually used in rural areas, TN-C-S is not allowed for farms etc. I guess it depends how 'rural' you mean.

All the properties near me are TN-S.

[richard.cs]

I'm not sure where these perceptions come from? The median age of buildings in the US is over 40 years, so there are equal numbers built since 1975 as those standing from before 1975. In Boston and New York, 19th century buildings (before electricity) are common, up to 20% according to census data.
If anything, I would expect the structures in older US cities to have greater median age because they were never carpet bombed.

In the UK we don't really consider 19th century building "old". I live in Southampton which was fairly heavily bombed but living in a 19th century house here is not at all unusual, and once you get a few miles outside the city nor is drinking in a 16th or 17th century pub.

[anfang]

Thank you all for the great discussion, I was just ranting against my landlord...

Anyway, my landlord says that because the flat has not undergone any major change, he doesn't have to install an earth wire, the question has already been discussed with the previous tenant.

What is the safest option now?

• Remove the earth-neutral cabling from the wall sockets?
• Leave the earth-neutral connection but check that the neutral pole is always connected to the neutral cable?

The sockets are all Schuko sockets, where the earth prongs are always exposed and that the whole installation is very shabby: there are rooms where only red cables have been used, other are black-only, another one had only neutral cables (true story... and I wondered why I could not get any fixture to work...).

[128er]

If I was in your situation, I would leave the PE-N jumper as they are and check all the connections at the sockets and in the circuit breaker box. And perhaps in the terminal boxes (right term? "Abzweigdosen") which you have access to. And on top of that (If you have access to one) you could also check all your sockets with an installation tester like the Gossen Metrawatt Profitest. You could check for example the mains impedance, Z_L-N.   

[electr_peter]

Safest option would be to remove N-E link and install RCD socket or RCD plug/socket adapter. Just in case something goes wrong. RCD only needs L and N to work, E is not needed.

In Lithuania N-E connection in the socket is very common practise because old and semi old buildings had only L/N wiring installed. Such practise is called "Inulinimas" in Lithuanian (literally means "zeroing" or "connecting to zero") in contrast to "Izeminimas" (proper grounding, "connecting to earth").

N-E connection in the socket is not the end of the world, but it is not a good thing. It leaves potential for L-N swap (which puts live on "earthed" metal parts) and leakage currents. However, because of lack of grounded appliances in near vicinity, earth impedance to a person might be slightly higher than in properly earthed installations (higher impedance - less potential current though a person). Depends on situation, of course.

[janoc]

In the UK we don't really consider 19th century building "old". I live in Southampton which was fairly heavily bombed but living in a 19th century house here is not at all unusual, and once you get a few miles outside the city nor is drinking in a 16th or 17th century pub.

You mean like the anecdote of my ex-colleague? He went to a conference in Oxford and was told that the event is in the "new building". After good 30 minutes of fruitless search of anything resembling modern he was shown a 600 years old building with a sign on the wall saying "New College". When he sarcastically observed what "old building" would then mean, he got pointed over to an 800 years old one ...

New can be pretty relative term, indeed. I am living in a town that has buildings standing (and still in use) remembering the times of Joan of Arc (she has been captured just outside of the city walls here).

[SteveyG]

Safest option would be to remove N-E link and install RCD socket or RCD plug/socket adapter. Just in case something goes wrong. RCD only needs L and N to work, E is not needed.

I disagree. Keep the connection in place but replace socket with an RCD model. At least then there are other methods for the RCD to correctly trip rather than just electric shock, e.g. if an internal line conductor were to contact the metal case.

[electr_peter]

Safest option would be to remove N-E link and install RCD socket or RCD plug/socket adapter. Just in case something goes wrong. RCD only needs L and N to work, E is not needed.

I disagree. Keep the connection in place[edit: N-E connection] but replace socket with an RCD model. At least then there are other methods for the RCD to correctly trip rather than just electric shock, e.g. if an internal line conductor were to contact the metal case.

Your suggestion is to keep N-E connected and add RCD after N-E connection. Good point, this would allow RCD to trip in more cases. Mains in (L+N) -> N-E connection -> RCD -> socket -> device. It could fit in a single socket.

Without N-E connected RCD would trip only when A) person touches live part or B) there is massive leakage current from live to outer metal case to earth. Case when metal is energised but too small leakage current flows would not be covered by RCD with N-E disconnected.