electrical wiring

[Fat Tone]

I don't know how your lighting circuits work, but in the UK I beleive that switching both live and neutral isn't usually an option. We tend to have a 'loop' that takes 3-core cable (Live, Neutral, Earth) to each light fitting. From there a similar cable goes down to a wall switch. This feeds live to the switch, which then returns it to the light, and from there to Neutral. Thus Neutral never goes near a switch.

[VJ]

Normal switches also only switch the live one.
But there are options that switch both live and neutral (and the home automation offers such components).

[Fat Tone]

Sure, but my point is the neutral wire remains in the ceiling and isn't available in the wall for switching.

[VJ]

Ah yes sorry... These lights are in a fake wall and are basically a built-in variant of a floor lamp (but using a wall switch and built-in light socket). Thus the neutral cable is right there.

But you do have a point that it may not be possible for the other lights... I don't know how they wire here in Poland, but it looks far more primitive compared how it has to be done in Belgium.

edit: in the home automation system I'm looking at, switches communicate wireless with the actuators. So you can install the actuator near that lamp where you have the neutral.

[VJ]

Well, I just removed the light switch... And I think some things are connected very weird. Just to give the full details. It concerns a fake wall behind the bed in it are 5 lights and two switches (2 controlled by one switch, 3 controlled by the other). Hidden in the fake wall is a junction box (it is painted over, and tucked away, so difficult to notice). I cannot open it to see how the cabling goes there. The switch is connected as one way (ok, it is the only switch controlling the lights).
Now for the weird things:
First, an imprint on the back of the switch (a metal one) indicates it should be earthed. This is not done.
Second (and I think most important) the earthwire is connected together with the switched output. Does this make any sense?

edit: Fat Tone, you were right, the neutral cable is not there... I'm a bit surprised it was done this way for the simple configuration, but at least there is a junction box that is accessible (which is an alternative to what you describe); the wireless home automation switch could go in there, but I would have to see if there is enough room for 2 switches.

Jörg

[degrub]

Don't know the electrical code there, but over here that would not be allowed except on old 240v appliances. Did the electrician check for back feed from another circuit ? ie voltage only where it should be ?

Maybe the box has a transformer inside and the lights are on DC ? or one phase of the AC ?

THe connection of the earthing wire and the output of the switch sounds like the "neutral" is being switched rather than the "hot" wire. Did the electrician see this ? check voltages ?
It almost sounds like the return is being switched on and off so what you are seeing with the lights is leakage current through the LED to somewhere since they may be hot all the time ? Get a volt meter and check.
i would be concerned about the metal box or switch not having an earth - if there is a path to it , there will be no bleed off and it will be "hot" and may go through you instead.

[LvR]

Well, I just removed the light switch... And I think some things are connected very weird. Just to give the full details. It concerns a fake wall behind the bed in it are 5 lights and two switches (2 controlled by one switch, 3 controlled by the other). Hidden in the fake wall is a junction box (it is painted over, and tucked away, so difficult to notice). I cannot open it to see how the cabling goes there. The switch is connected as one way (ok, it is the only switch controlling the lights).
Now for the weird things:
First, an imprint on the back of the switch (a metal one) indicates it should be earthed. This is not done.
Second (and I think most important) the earthwire is connected together with the switched output. Does this make any sense?

edit: Fat Tone, you were right, the neutral cable is not there... I'm a bit surprised it was done this way for the simple configuration, but at least there is a junction box that is accessible (which is an alternative to what you describe); the wireless home automation switch could go in there, but I would have to see if there is enough room for 2 switches.

Jörg

I would give that sparky that just tested your wiring a royal kick up the pants .................. earth connected together with anything is the most basic of no-nos to check for. The mere fact that you can actually say that and not complain that your earth leakage breaker keeps tripping is a sure indication of a disaster waiting to happen.

In the end, neutral and earth is the same, but they are kept apart so that any leakage dangerous to humans can be detected - any current flowing through earth (or then via earth to neutral) must trigger your home's protection breaker. ITO optimal safety, that metal junction box must be earthed - at the same time its not going to change the behavior of the LED lamps if the rest of the current wiring is ok and the box is not earthed.

Me? - I would rip out that whole lot, and redo it properly starting right from the switch with a proven solid earth available , but most of all, have that earth leakage breaker presence/operation tested by inducing a small leakage current in every junction box and plug-point in the house (get a sparky with the proper tools) and then confirm the breaker trips at around 5mA or whatever your code says its supposed to trip at.

[VJ]

The problem is that I think the regulations here in Poland are quite open, and many people just do something and if it works it is ok. Many buildings here have no earth connected (so I can't even be sure that the earth wire is grounded). In Belgium, an apartment of my size would have about 20 fuses (e.g. lights and sockets seperately, seperate circuits for each room, seperate circuits for some appliances); here the whole apartment has 3 fuses. And that is all. Nothing else in the fusebox. And it beats my previous apartment, which had 2 fuses that you screw in like a lightbulb.

The switch I opened is a 2-way switch with one half connected (only switch that controls the lights); it has 1 connection at the top and two at the bottom. At the top, a brown wire is connected, and at one connection both the blue and yellow/green cable are. The switch has an attachment for an earthwire, but this is not used.
I decided to open another switch, one that has two buttons and switches 2 circuits. This switch just looks like the previous one, but with all components double. For each circuit, the switch is the only one. Here, the brown wire goes to the top of the first switch, and then to the top of the second one. The blue wire is attached to the bottom of one switch, the yellow/green wire to the bottom of the other!

So it looks to me like they just ignored all colour codes and simply use a normal 3 wire cable (brown, blue and yellow/green, and used these cables for the wiring. In the double switch, I assume the blue one will be the switched phase for the first circuit and the yellow/green one the switched phase for the second circuit. If they did the same in the bedroom, it might well be that the blue cable is the switched phase for one lamp and the green/yellow cable is the switched phase for the second lamp rather than the earthwire.

The electrician did not open the switch, as he said the problem with the led lamp is to be expected in an old bulding. Even when I told him the electricity was put here 2 years ago, he said it can happen. Replacing the cabling implies breaking into all the walls, as they do not use plastic tubes. In the bedroom, this concerns a fake wall where access should be easier, but in the other rooms it wold be a disaster. And can you imagine the electricity was place here 2 years ago! :angry:

I hadn't thought some many renovations where necessary... They assured me the electricity was new, and while it is true, it does not mean it is good. The problem is that I think this is the current level of "normal" here... So as an easy solution, I'm more considering the home automation. I was not planning on doing it for the lights, but it seems like a solution that solves all dangers with the least intrusive work: the actuators are installed near the lights; the switches are battery powered switches that communicate wirelessly with them. This would allow me to not use the cabling that is present (apart from the live/neutral/ground connecting the lights).

[Rakido]

It's the bedroom? Use candles

Seriously i'd go with LvR and redo it properly, that really doesn't sound like a safe installment

[VJ]

On the whole, I agree and I would also have it redone... but it would be a disaster: throughout the apartment there are built in wardrobes, fake ceilings, custom finished walls, builtin in ceiling lamps,new floors, new walls ... it was renovated 2 years ago . I had planned to do some renovations to solve some of their stupid decissions (e.g. thermostats fitted inside the encasing of the radiator, encasings you cannot remove to clean or for mainenance, ...). Having to basically destroy it all and put it back up would be a nightmare. There also is no wiring diagram, so no idea as to where the cables go. And as they are not put in platic tubes, rewiring effectively means breaking open the walls (even if you leave the old cables and decide not to use them, you need to put the new ones in). I've only spotted 2 junction boxes and they are in quite unlogical places... Even using those on-the wall cables gutters (e.g. possible where the floor meets the wall) is made impossible due to the layout and the floors.

And people tell me the electricity in this one is quite good!
(to given an example: in my previous apartment, the lights dimmed when somebody called an elevator)

I'm not sure the electrician who came to my place would do a better job; I actually think he was involved in it (+ there is a language issue) and it really seems this is the standard here. I'll talk to the home automation installer: perhaps the system with wireless switches would allow for a minimum of destruction (e.g. just work near the light fixtures).

[degrub]

What you describe is a system without safety ground. This works if users are all double insulated so that any internal fault does not go to the external case - and then to you. So just wear your rubber insulated shoes all the time and don't touch something else at the same time that might be connected to earth . It's been std wiring practice everywhere in the world at one time or another. Its not a big issue if equipment is designed for it.

Hopefully the green/yellow cable is same gauge as the brown and blue, otherwise you will have to watch out on the loads where it is used.

Things that need a safety ground, like computer case power supplies, consider finding a water pipe to attach the safety ground to. You can find out if that is a good path to earth by pushing some stiff wire into the dirt and then running a small wire up to the pipe location. Then just measure the resistance between the wire and the pipe. If it is less the 1Mohm, you probably have a reasonable earthing path. If not, then there is a break somewhere. The danger is if they ever work on the pipe and disconnect the earthing.

i don't know that the home automation system is going to improve the safety any. But it is a neat project.

i would take a volt meter and verify that the voltages are correct on each side of the switches - look for leaky ones and for voltages that are not correct - ie backfeed on a "neutral". Those need to be fixed if you find any.

[VJ]

I don't think all the users are double insulated: normal appliances, light fixtures, light switches, ...

As far as I can tell, the green/yellow wire is only used this way in the two light switches I described. In the other lightswitches, other cable is used: they have very thick isolation and are not wrapped together. And they are all the same colour (all white in one switch, all black in another)... So even though they told me electricity was renewed, it was not done very thoroughly...

I'm on an apartment on the 4th floor, so measuring the resistance like you described is not an option. In all the sockets, the wiring looks correct, and there is a ground wire connected (this was not the case in my previous apartment). I'll have to find out if the ground is really connected still (I do experience far less static buildup than in my previous apartment).

From the looks of things, they messed up the light switch cables; the rest looks ok (at least as how it is custom here). The home automation system would allow me to not use the cables to the switches: the lights gets its power directly, no branches to switches, and the switches are wireless and get power from a battery (no possibility for shock or anything - the EnOcean system actually has switches that don't even need a battery: the sheer movement of the switch supplies enough power ).
I need at least part of the home automation to get the thermostats working properly, I'll talk with the installer about my other options: due to the thermostats, I need some central control unit, so the added costs of the lights should be ok. The problem I see now is that I don't see all junction boxes (if they used them), so it might be tricky to find just where the branching from the lights to the respective switches is. But he may have tools for that or experience with that (the lights are in a lowered ceiling).

I did learn that there are no standards or regulations whatsoever here regarding electricity...

[MultimediaMan]

It sounds like your lights were wired in Series rather than Parallel.

[LvR]

It sounds like your lights were wired in Series rather than Parallel.

What makes you say that?

[MultimediaMan]

Because that is exactly how light bulbs of different wattages wired in series behave, particularly an LED and an incandescent. One will shine and the other will not.

I would bet he has something like this: Hot Lead->Switch->LED Input->LED NEUTRAL->Incandescent Input->Incandescent NEUTRAL->Neutral

In a parallel circuit, both loads receive equal voltage because there are multiple paths to ground.

He should have: Hot Lead->Switch->Hot to LED Input AND ->Hot to Incandescent Input. Both the LED NEUTRAL and Incandescent NEUTRAL leads should be wired to Neutral.

Remember the PIE Chart...