Wall socket traps in old slab blocks - Page 1
Forum section: electronics / general

author: mrkev
author_rank: Regular Contributor
timestamp: June 08, 2015, 11:32:25 pm
content: So yesterday I've noticed something funny with one of my wall sockets. I've checked it out and bingo, the PEN (the most epic invention ever - PE and N wire together) was loose under the screw. Thus everything connected to sockets in next room was basically floating at live potential...I live with 4 other people in a rented old slab block flat. And they really made the power net shitty back in the day (communistic regime pressed on building huge amount of cheap flats). So it's all in aluminum TN-C config, that stuff is just crazy.Today i decided to check every socked and found this (image below). I don't know how, but i managed to run my PC from this socket whole year. Live wire connected on the wrong side (should be left) and I really don't know how, but it had connection to PEN from a wire that was coming from the earthing screw...Best part is, that the remains were nowhere in the socket box, so someone really "clever" left it like this on purpose...Damn I'm gonna check everything as soon as I move to the new flat next time...

author: free_electron
author_rank: Super Contributor
timestamp: June 08, 2015, 11:47:31 pm
content: holy crap. what a shit design...

author: Delta
author_rank: Super Contributor
timestamp: June 09, 2015, 01:01:26 am
content: TN-C?! Wow! That shit has been illegal here in Blighty for a long long time!Stay safe, brother.

author: mrkev
author_rank: Regular Contributor
timestamp: June 09, 2015, 01:27:41 am
content: Quote from: Delta on June 09, 2015, 01:01:26 amIt is illegal for new installations for more than twenty years here, today's standard is TN-S (or at least TN-C-S for reconstruction), but there are still many networks that are older than that and reconstruction would be so pricy that no one wants to do it (you would have to hack out new grooves for cables).F.e. in my case, they put the cables in the floor, no way it could be easily changed. Plus I am not the owner of the flat...

author: calexanian
author_rank: Super Contributor
timestamp: June 09, 2015, 04:01:48 am
content: Yuck... I am a yank and am not familiar with those. Did a quick lookup. Yikes! combined neutral and earth. Its all fun and games until something goes wrong. Then its just fun... as you dance around. In pain. and your house burns down..

author: mrkev
author_rank: Regular Contributor
timestamp: June 09, 2015, 06:54:25 pm
content: Quote from: calexanian on June 09, 2015, 04:01:48 amYeah. And the biggest problem isn't really the TN-C system, it's its combo with aluminum wires. They tend to get loose under screw or even break (the normal operation span is more than few decades). And when it's the PEN that broke, you will get live on every metal cover of 1st class device (device with earth connection) in chain after...And the only reason why they used it (and why it was invented) is the price, no other advantage at all.Btw. It was actually standard to use proper copper and TN-S before II WW and I have even seen installations madebefore 80 yearsand they were in better shape...

author: mrkev
author_rank: Regular Contributor
timestamp: June 10, 2015, 05:44:47 pm
content: Quote from: datumplane on June 10, 2015, 07:25:43 amOur norm says that live has to be on the left side (earth pin on top). I don't care about the rest of EU, but you won't get final building approval if you connect live on the right side, practically nowhere in Middle Europe... So yes, there IS a wrong side...And sure, you can't assume where the live is, because you never know if some hobbyist didn't connect it the wrong way around, not because there isn't any regulation on how it should be...

author: MiataMuc
author_rank: Regular Contributor
timestamp: June 10, 2015, 07:18:45 pm
content: Just for interest.. as I live in Germany and I'm being used to not knowing the polarity of sockets - why would one need to? Except for some extreme rare cases the most appliances don't bother... (there seem to be some problems with gas heating systems, when someone fits them with a plug..).

author: mrkev
author_rank: Regular Contributor
timestamp: June 10, 2015, 07:40:37 pm
content: Quote from: MiataMuc on June 10, 2015, 07:18:45 pmYou wouldn't. It's just for backward compatibility - some really old devices had just one pole switch, breaking only line. Now they have to has two pole sw., breaking both neutral and live. It's better to fuse the line wire.You can save money, because you know which wire is line. Thus use of easier input filter, advanced safety only for live side (otherwise you would have to protect both equally), etc.It doesn't really matter nowadays as devices are usually made for whole EU (or even world) market... So they count with live & neutral pins exchangeable. Plus almost everything now is 2nd class device (only two pin plug) and those were always done exchangable...

author: calexanian
author_rank: Super Contributor
timestamp: June 10, 2015, 08:38:56 pm
content: I will keep my separate neutral and ground for my household appliances thank you very much. Now as for on my work bench while kleudging, a paper clip makes a fine 30 amp mains spring terminal!No worries there!