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

[anfang]

A light was flickering and I said to myself: it is time to change that old wall socket. I unmounted the Schuko socket and found... the neutral cable connected to the earth prongs and no earth connection! How is that OK? Isn't it extremely dangerous? And the connection has been done on purpose. Why?

On top of that, the cables are all black, both the live and the neutral cable.

The landlord will have a thing or two to explain...

I took this photo. In blue the piece of wire connecting the neutral to the earth prongs.

[bktemp]

I don't know for Austria, but in Germany you see this quite often in older houses with the electric installation done about 40 years ago. For new installations it is not allowed anymore because a RCD ("FI") is mandatory since 2009. But there is no need to change existing installations.
It is not really dangerous, but there is no ground fault protection.

[Kilrah]

In Switzerland it's the same, old installations had earth and neutral connected and old buildings do not need to be upgraded until the next major overhaul.

[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.

TN-C: combined PE and N conductor all the way from the transformer to the consuming device.

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

[wraper]

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.

[wraper]

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. because of:

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

[jahonen]

This was the common way here in Finland until relatively recently (I think sometime during 90's this changed to present way). But from fault protection perspective (which is the purpose of the appliance PE connection), that connection works ok'ish. It blows fuse in case the device housing develops a short to L conductor. Note that even although the PE might seem to come somewhere else (green-yellow wire exists), it might actually come from nearby junction box, so presence of the green-yellow wire does not guarantee that PE is wired into actual distribution panel.

Nowadays, the system used here in Finland is TN-C-S so that neutral (PEN) is splitted into PE and N on main distribution panel (this point is also connected to grounding electrode around the building foundation), and PE and N will never be merged afterwards. All PE conductors are guaranteed not to be derived from N wire in any other place than from the main distribution panel PE-N connection.

Regards,
Janne

[janoc]

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.

Which happens especially in old buildings that actually lack the third - earth - wire. Which was very common in older installations in Slovakia - the earth pin was wired to the right (neutral) contact too and there were only 2 wires going to the outlet. So this is really a bad idea.

[128er]

It is neither pretty nor safe. But better as none PE connection at all. The common term for this in german is "klassische Nullung" . And as wraper said, if your neutral becomes bad, the device can be at live voltage.

[rstofer]

If you consider a ground fault of high magnitude occurring on ANY circuit connected to the transformer (even in your neighbor's house) and you toss in the fact that the fault current MUST get back to the neutral point of the transformer (to complete the circuit), every grounded neutral in the system is going to be carrying some portion of that fault current.

The fault current goes to ground then gets into the neutrals (because they are connected to grounding conductors) and then flows on to the transformer neutral point.

In the US, fault current for residential locations is usually less than 10,000 amps and likely less than 5,000 amps but, still, the damage than can be done by fault current flowing in small neutral conductors can be substantial.

Ordinarily, the neutral is grounded at the transformer and again at the service entrance point and nowhere beyond that point.

[chris_leyson]

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.

[Cubdriver]

Here in the US it's sometimes called a bootleg ground, and is against code.  I'd expect it likely is where you are, too.  It's definitely dangerous if you think about it - if the neutral somehow opens up between the connections at the receptacle and the panel, then the neutral pin on the plug will be pulled high by whatever is plugged in to it.  This will also pull the ground pin high as they're tied together, and if the device has a 'grounded' metal enclosure, it's now at near line potential. Yike!!

-Pat

[Brumby]

Neutral and earth are the same thing.

In terms of voltage reference - then, yes.  But in terms of current flow, especially in fault conditions, then it's not so clear.

From what other posters have stated, this arrangement is not uncommon in older installations in some areas - but as has also been stated, it's not a great idea.  It's not inherently dangerous - just far less than ideal in a fault condition.

As far as RCD protection is concerned - if a person bridges the active of an appliance and the casing of that appliance, then there will be no protection.

However - if the neutral is earthed at some point (preferably at the entry to the building) then there will be RCD protection if someone were to bridge the active of the appliance to another earth-connected conductor, such as a metal water pipe.

[EEVblog]

Not legal in Australia.

[rob77]

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.

it's called 2 wire and it's legal...but it's not legal for NEW installations (unless the cross-section of the PEN wire is at least 16mm2).  btw... it was a pretty common setup in the past, but nowadays 3 wire installation is mandatory with separated N end PE.
one of the reasons why separated N and PE is required is the fact that you have to have a RCD protection on all all outlets in a household. i think the whole EU is more-or-less aligned so it will be very similar everywhere else.

[Red Squirrel]

Not right to do that, but technically it should be ok.  Not the way I would do it though...

Basically the neutral is tied to ground at the panel, but after that it's NOT suppose to be connected and suppose to be treated as two separate things.

My guess is this is an old install and there is no ground wire at all, so they did this to compensate.  The better way of doing it is to install a GFCI outlet there.  While it won't be grounded, it will trip if there is a fault.   Ex: a light fixture chassis gets energized for some reason, normally it would go to ground and trip the breaker, but since there is no ground it won't do anything and be a danger to anyone that touches it.  With a GFCI if you touch it and some of the power goes through you and to ground, then it will trip the GFCI. 

A fun experiment though is you can put a paper clip in the neutral side of a plug and not get shocked.  Great way to freak out friends!  Just make sure it's wired correctly before you try that trick unless you want a perm. 

[AlfBaz]

Ignoring RCD's, GFCI's etc for the moment, as many domestic installations still don't have them, then...

Earth should only ever carry current in a fault condition. Neutral, on the other hand, is a current carrying conductor. It has flowing through it the complete load current.

If there is any voltage drop (and basic oms law will show that there always be some, more if there are bad connections or undersized wiring) and you connect earth to it at the outlet, you are essentially raising the potential of any grounded chassis with respect to any other grounded item nearby that is not powered or is earthed "incidentally", such as a steel sink via metal plumbing. This "small" potential difference has very small source impedance and under the right conditions can cause sufficient current flow to cause death or fire

[Brumby]

A fun experiment though is you can put a paper clip in the neutral side of a plug and not get shocked.  Great way to freak out friends!  Just make sure it's wired correctly before you try that trick unless you want a perm. 

While most of us here will understand what you would be doing here - I would strongly advise NOT.  If you have someone who doesn't know what's going on see you do it - or heard about it second hand - and tried it themselves, then there is a high risk of something bad happening.  Add to this the fact that there is no good reason for doing this other than 'freak out' value and it's not something I'd encourage in any way.

I actually go the opposite way and keep any such activities to myself - and even in those, I keep a healthy respect for the old saying "One flash and you're ash."

[SteveyG]

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.

It's against wiring regulations, but certainly not illegal. No crime is being committed!

[focovario]

"It's illegal and doesn't meet wiring standards unless you live in a so called third world country where nobody give a shit".

I am sure chris_leyson can convey his technical wisdom without offending people from other nations on an open forum. To express such a strong opinion I gather he has extensively traveled the world. If that is the case, he certainly has been meeting the wrong people. 

[focovario]

Apology for misquoting chris–leyton.

This is what he wrote:
It's illegal and doesn't meet wiring standards unless you live in a so called third world country where nobody give a shit".

This is my opinion:
I am sure chris_leyson can convey his technical wisdom without offending people from other nations on an open forum. To express such a strong opinion I gather he has extensively traveled the world. If that is the case, he certainly has been meeting the wrong people. 

[DenzilPenberthy]

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.

It's against wiring regulations, but certainly not illegal. No crime is being committed!

In the UK it's prohibited in installations covered by BS7671 aka 'the wiring regs' but as you point out, this is not 'illegal'.

It is however also prohibited by the  Electricity Safety, Quality and Continuity Regulations 2002. Part II, paragraph 8, (4) "A consumer shall not combine the neutral and protective functions in a single conductor
in his consumer’s installation."  I believe this does make it illegal. 

I'm very happy to be corrected by any passing lawyers or people who've read the ESQCR in more depth than I have...

[TassiloH]

This was common in Germany and adjacent countries between the 1950ies and 1970ies. As someone else said, "klassische Nullung". It would be quasi-illegal in new installations or when an existing installation is overhauled or largely modified, but otherwise the standard when the electrical system was originally installed still applies (in Germany, "Bestandsschutz"), so there is no legal need to upgrade it to current code regulations.
The problems with this kind of installation are:
* No RCD (unless you install an RCD-Outlet combo for each outlet)
* grounded equipment is on live potential if wiring between outlet and distribution box fails
* PE and N share a wire, so if a high current device is connected, the PE potential of the outlet will shift a few volts compared to real ground (voltage drop over the wire) and also compared to other, less loaded outlets. If you have grounded audio or computer equipment connected to the outlets and you run a data or audio cable between them, a rather large current could run via the ground of the data cable dut to the different PE potentials.

[tszaboo]

It is neither pretty nor safe. But better as none PE connection at all. The common term for this in german is "klassische Nullung" . And as wraper said, if your neutral becomes bad, the device can be at live voltage.

This. The house does not have earth wire.
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.

[Jeroen3]

If the pole in your street falls over and the engineer connects L/N the wrong way your PE is live. 
I'd recommend to:
- Properly wire earth.
Or, lazy approach:
- Remove earth fault, and replace socket for Type C.