When ever I’m asked to give an estimate for how long a project will take, my answer is “two weeks.” Love that movie!
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Same in Denmark.
In Denmark, there is not a “specifically for lightning”. It all depends on the fuse used on the wires. Normally it would be 10amp or 13amp fuses for ligthing and outlets.
If you fit a pin socket/anything which only can handle 5amp, you´ll need to change the fuse as well, and make sure the user cant exchange the fuse to something bigger even by accident.
Thats the same in Denmark. However, we have had codes for many years, (I guess since eletricity was invented or thats how it feels like sometimes), which means, that often you´ll either know what to expect, or if you run into “something”, you´ll already know how to deal with it. Ofcouse it can mean the budget will get higher, but it´s limited in many ways, as there has always been somekind of code/how to do electrical installations.
The worse problem I have meat, is entering a home where a non-educated electrician (most often the owner of the house) has done some DIY. Thats can be very hard sometimes. It´s illegal in Denmark, btw. To change/fix/repair the electrical installations, you´ll have to be educated, and there have to be a person behind which have the legal official licens. This person/company will become responsible for the installation afterwards.
Not to beat this to death, but about 30+ years ago, the French code (at least some houses I’ve seen), used red/green for live/neutral … which kind of makes sense, unless you’re color blind … and then you cannot work as Electrician.
The other twist is that most houses/buildings had 4 wires coming in the the house (the so-called Y-configuration in three-phase circuits).This gave the option to the home-owner to choose 120/220 Volts. If you chose 120, you have one neutral + 1 live … if you choose 220V, you have 2 live wires in each plug … and red/green did not matter any more. Things have changed a bit since then, as most/all houses were upgraded to 220V.
The Europeans might laugh at this, we use 120V only in the US, which causes electrical cables to heat-up more than in Europe, and hence, sometimes we use thicker-gauge copper wire … A colleague from Germany once complained that the wires for his appliances were heating-up more than he remembers when he was in Germany.
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Hi everyone!
I guess it is a common “problem” everywhere. I put it in quotes because i would say that in fact not running a neutral wire to a switch is a legacy practice, which has started to slowly fade away with the advent of smart equipment.
Yes, you have to do the whole house remodeling. It is difficult for me to estimate, sorry, i do not live in the US.
On our local market, however, there are wireless battery-powered solutions.So you could check for this option too. However, i would say it’s kind of a poor man solution, because the more batteries you have, the more of them are drained, so there is always something not working, and it is annoying.
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Hi,
I’m the poor guy from the horror story of undocumented KNX system that I have found in my new apartment, but the region is middle east Dubai area, not Germany.
Anyway, openhab is now controlling 100% of that system (all the lights, dimmers and air conditioning) and much more (integrated home cinema, tv, kodi etc…It was a fun summer project, I would say still much much easier and cheaper then rewiring existing house with new wires, neutral or whatever 
All you have to do basically is to listen to the knx bus and press all the buttons in the house to write down their group addresses…
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Interesting.
Metal tubing was mandatory in Belgium until the 1970s where they realized that it represents a short-circuit fire hazard. Nowadays, all electric tubing is done in PVC.
Neutral wiring is also mandatory everywhere for more than 40 years, for safety reasons. I suppose this was imposed about the time when Europe moved away from 110VAC to 230VAC.
Likewise, to my knowledge the Belgian electric regulation (AREI in Dutch) strictly forbids combining power and data wires in one tube.
This thread is fascinating, I’m really learning lots about how different countries approach exactly the same questions / challenges.
The basic rule in the UK is the same, “Low Voltage” (mains) should always be contained away from “Extra Low Voltage” (sub 50v)
However, there is a little known fact, that if the insulation around the cables are rated equal to the highest required for the ‘bundle’ then it is acceptable.
I believe that rule is used at temporary events, where it would be impossible to isolate mains voltage from anything else.
(I was installing a massive data network at an event last week and we were using external grade Cat5 or FibreOptic, with 500v insulation)
Regarding the missing neutral wire in switches. In Denmark we have “solved” this pretty easy, as there is a un-written rule (code), to place an outlet together with a switch, just next to the door when entering a room (or strategic placed).
Here is an example of how it looks from the outside.
On the left: (just right next to the door)
The grey device to the left is the old (more than 40 years old) way of doing it. It consists of a single switch and an outlet. The outlet (bottom of the grey device) is actually a switch/outlet in combination. It was required in the old days to be able to turn on/off the outlet. Its no longer required.
On the right:
The white device is the newer Fuga combination by LK (Laurits Knudsen), which is in used in most places in Denmark.
The combination consist of, (from top to bottom): One single switch, one dual switch and one outlet (notice the outlet without the switch to turn it on/off).
Having this sort of combination there will always be a neutral wire available.
Many many years ago we also had metal pipes. I´m not sure if it´s still legal to use, but I´m pretty sure its no longer available. And havnt been for at least 30 years. Whats even worse, we also had cotton/fabric isolated wires. A very bad combination when watering entering the pipes.
In at least the last 40 years, buildings have been build using PVC pipes and PVC isolated wires.
There are still buildings here, which consist of metal pibes and cotton isolated wires 
The worse problem in Denmark is, that the above solution may look good (better) and is pretty smart, as the wall boxes behind is build as gauge/combi sizes from what the user need.
But the problem is, the wall boxes behind is nowhere near any sorts of standard size. Its very small like 50x50mm for a single switch (the width is always the same).
This means, whenever a building is build using Fuga wall boxes, it´s forced to Fuga modules (switches, outlets, dimmers etc) as well, and nothing else.
An example, I cant exhange a switch with a EU size switch. At least not unless I rip out the wall box, and exchange it with an EU size wall box. Atm I´m facing this situation personally, cause I´m testing some Velbus equipment (panels). I cant fit the panels unless I exchange the wall box. Thats not a small peace of rebuilding done in a weekend.
Fortunatly many newer buildings are builded using EU-sized material in the last coupple of years… Beside beeing cheaper it opens up a more flexible market, specially regarding smarthome switches etc.
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The US mandates a separate “bonding” grounding wire separate from the Neutral. One of my coworkers has used that wire instead of a neutral wire but I am not sure the safety of such a use.
There is a long answer…
Do you want it?
Or will this short answer be enough -
“It will work, under certain conditions and until something goes wrong”
What I can tell you is that your co-worker / colleague / friend doesn’t have any kind of earth leakage protection in their installation.
Which is something to correct soon.
But… should one be installed, it’ll keep disconnecting due to the incorrect use of the ground / earth wire.
In the US (and Canada), the Neutral and Earth wire are both connected to Earth in the main electrical panel.
Indeed, as they are in the UK, except they tend to be connected outside of the property, on a PME basis.
So the property must consider neutral and earth as totally separate.
What we must do is put an earth leakage (RCD - Residual Current Device) (balanced load checking) between the Live and Neutral and the various circuits.
Where the Earth wire / bond is the safety, to ensure that erroneous current is sunk to ground, rather than through some poor souls body.
(Path of least resistance etc)
Where (for example) the “RCD” should detect an absolute minimum of 30ma for a duration of 30ms
Better units detect 3ma for 3ms.
And the “DP MCB” is an over current device, normally 80 amp or 100 amp for domestic installations.
What this diagram doesn’t show (for the UK) is that outside of the property, the Neutral side is bonded to ground, rather than the earth being bonded to Neutral. (Which obviously it is, but it’s a “correct” way to think of it)
So that measuring Live / Hot to Neutral should give the same result as measuring Live / Hot to Earth (including physically sticking a copper rod into the ground {brown stuff in the back yard, for comedy reference})
The important detail I’m trying to make is that the Neutral and Earth are bonded together, before the main breaker.
If they were bonded after the main breaker / RCD, the earth safety would be utterly pointless.
MCB - Mains Circuit Breaker
DP - Double Pole
SP - Single Pole
RCD - Residual Current Detector
RCBO - Residual Current Circuit Breaker with Overcurrent Protection.
Example RCBO & RCD schematic, where the circuit is cut when the load is unbalanced across the breaker.
As you can see by the placement of the test circuit.
Live from after the coil, Neutral from before the coil
My apologies if I’m teaching anyone to suck eggs here.
Most circuit breakers in the US just open the Hot wire. For some newer style ground fault & arc fault breakers, the neutral wire goes through the breaker. but they are usually fewer than the standard hot-only breaker.
In theory, if the neutral and earth are bonded (because they are essentially the same, unless we start talking about generators) then only cutting the Live / Hot wire, would be absolutely fine.
The important detail being to protect the user downstream, by cutting power when a fault is detected.
Earth leakage, over current etc etc
Exactly the same in Denmark…
If someone uses the earth wire as neutral, it will disconnect the installation (all of it) in Denmark, cause we have a “Safety Breaker” relay (In Denmark its called HPFI relay) which will disconnect all power, if there is more than 30mA between the live/neutral and the earth wire. I think these are the english terms of the same relay/same principal:
GFCI - Ground Fault Circuit Interrupter
ELCB - Earth Leakage Circuit Breaker
RCD - Residual Current Device
RCCB - Residual Current Circuit Breaker
And I agree with Stuart, if someone uses the earth wire as neutral after the main breaker, (even though it may work) things can go seriously wrong.
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There are a lot of replies, so i won’t quote, but let me clarify one thing. In the US 99% (or maybe 100?) of private houses are built of plywood, so it’s quite logical that they mandate metal pipes.
It depends what you call house … If it’s a single family house (2-levels), then YES the houses are primarily built of wood. If it’s a high rise building as in large metropolitan areas, then NO, there the ‘skeleton/frame’ of the building is metallic.
As for metal pipes, that really depends on the actual State (Province). In some states (e.g. Michigan) no metal pipes are required.
@JB_63 I said PRIVATE house. I meant own house for a family. Of course metropolitan building is a different story
@JB_63 By the way, regarding your initial question, i’ve remembered one thing which potentially could save you from a lot of cost and troubles. Have you actually inspected your switches and wires coming to them? For example here in Russia there’s a common practice to do all the wiring using a single type of 3-wire cable (L, N and PE). It’s just easier for workers to manage one big supply of a single type than several different smaller supplies. So, as a result cables running from junction boxes to switches also have 3 wires, with one being unused. And if you’re lucky you may find your house having the same feature. You can pick up and use this wire, and it will cost you only rewiring junction boxes. Of course this is way less destructive, even if your junction boxes are hidden in walls.
Do you live in family house or apartment, BTW ?