electrical wiring
October 4, 2005 11:32 AM   Subscribe

yesterday i was wiring up a room(mains ring and sockets) for a friend. It turns out i did it wrong by thinking blue was live and brown neutral, but anything plugged into the sockets works fine.Is it safe to leave it like this? I can distinctly remember being taught in school bLue=Live browN=Neutral I'm 24 and from n.ireland, does anybody else remember being taught this or did i just make it up?

also i think two sockets are wired correctly(brown-live......blue-neutral)....that cant be safe can it? with the others being wired the opposite way but how is it still working ok?
posted by quantumonkey to Technology (16 answers total)
The fuse is meant to be in the live wire. If the fuse blows now it'll just cut off neutral, which can't be good. I'd get it fixed.

"The live brown bear sits on the yellow/green earth looking at the neutral blue sky"
posted by cillit bang at 11:39 AM on October 4, 2005

It's not clear if you mean you've hooked up the live wire going to the neutral pin on the socket and vice versa (which is potentially very dangerous and should be fixed), or if you're just running the wrong coloured wires to the right pins (which is electrically safe, but non-standard, and should be changed for consistency and probably to remain compliant with electrical codes in your area).
posted by cardboard at 11:42 AM on October 4, 2005

i think its the live to the neutral and vice versa
should it not work if it's like this?
posted by quantumonkey at 11:54 AM on October 4, 2005

Indeed, blue should be neutral and brown should be live. You should definitely get them wired correctly and consistently.

For many devices, it doesn't matter which wire is which between the live and the neutral. These appliances often have standard non-polarized two-prong plugs. Those for which it does matter have polarized plugs, and those devices may be damaged by incorrect wiring, although I can't see under what circumstances there would be any electrocution hazard involved. Of course, either kind of device could have a 3-prong plug. So the point is, just because your table lamp works fine in a reversed-polarity outlet doesn't mean your computer won't need a new power supply after you plug it in there.

Consider investing in an outlet tester, which will be relatively cheap at a home improvement store and can tell you at a glance whether the wiring is right.

If you just have the colors wrong, as cardboard said, it'll work fine now, but consider the safety and sanity of the next person to work on the wiring.
posted by musicinmybrain at 11:56 AM on October 4, 2005

More information on plug-in outlet testers and some examples of circumstances under which hot/neutral reversal actually could be dangerous.
posted by musicinmybrain at 12:06 PM on October 4, 2005

It's quite unsafe. Change it. Like cillit bang said, if all the circuit breaker / fuse does is cut off the neutral you are left with a live wire even after the circuit has tripped. Hope you aren't grounded when you touch it.
posted by caddis at 12:23 PM on October 4, 2005

And since in N. Ireland you're likely to have switched 240V sockets, you'll now have a neutral connection that's live all the time. Rewire it before you kill someone.
posted by scruss at 12:34 PM on October 4, 2005

If the socket is wired correctly, but with the wrong colored wires, you can "fix" it with colored vinyl tape -- you tape a length of the correct color around the insulator of the wire, so that the wire are marked correctly.

This is why they sell multiple colors, and why it is *not* code to just use black tape to insulate a splice in the US (since that marks the wire as a AC Hot line in the US.) The right way to splice, btw, is wire nuts, which don't obscure the insulator color.

As clillit bang and caddis said -- if it is wired backwards, so that the fuse is on the neutral wire, rather than the hot wire, this is a very serious safety issue. Do *NOT* color-tape a wire to hot unless it is, in fact, the hot wire. The right answer is to rewire both ends, but color tape at least will warn the next guy that the outlet isn't quite right, and he needs to pay attention, and means that some well meaning person in the future doesn't "correct" the problem, leaving the outlet with a reversed hot-neutral.

Finally, retaping may not be legal in your area.

In general, if the question is "Can I do this weird out-of-spec thing with my electrical service" the answer is "NO!" It's a huge safety issue, and it's one that can lurk for years, then bite. You may remember the out-of-spec wire, but houses can last a long time, and somebody down the road may be hurt badly.
posted by eriko at 12:37 PM on October 4, 2005

yesterday i was wiring up a room(mains ring and sockets) for a friend. It turns out i did it wrong by thinking blue was live and brown neutral

If this comes out in the wash, their home insurance could be deemed invalid in case of fire and/or you could be pursued for negligent work. So you might want to cover this up or fix it.
posted by wackybrit at 1:14 PM on October 4, 2005

You have a choice: Do it right or hire an electrician!

Electrical systems in houses are very simple, but every single detail is very important. This goes from getting the colours matching correctly to making sure you loop wires around screws in a clockwise fashion (so that tightening the screw tightens the loop of wire).

I really wish we still had big:
Do it right or hire an electrician!

Every detail is important!
posted by Chuckles at 1:24 PM on October 4, 2005

posted by caddis at 2:25 PM on October 4, 2005

It's funny, I was just talking about this. I'm 26 and from N Ireland. You've gotten confused - what you were taught was..

bLue = left
bRown = right

Easily done..
posted by ascullion at 2:40 PM on October 4, 2005

"Rewire it before you kill someone."

Do it now. Right now. Otherwise, you will forget, and leave a trap for some poor bastard who comes after you.

Of course that poor bastard could be your mate. Oops.
posted by i_am_joe's_spleen at 4:05 PM on October 4, 2005

Do it right now before someone dies. Also, note that home insurance could be nullified and your friend could be left liable if something happened to someone else. And, when your friend sells, they probably have to sign docs saying they aren't aware of any work that isn't done to code. Your friend could be left on the hook if the next owner is injured, if s/he signed off on that.
posted by acoutu at 4:53 PM on October 4, 2005

Here is a simple guide - with colour pictures - to what a properly wired plug should look like in the UK. You are probably already aware that not all devices have an earth wire, so you just ignore the green/yellow wire in the diagrams if there isn't one in the cable you're connecting the plug too.
posted by biffa at 2:34 AM on October 5, 2005

If by 'mains ring' you mean the wire hidden in the wall that goes from socket to socket, I think you've got problems.

If you used sheathed wiring that contained blue and brown insulated wires, for wiring up a ringmain, there's a good chance that the place will burn down. Ringmain is black/red insulated single-core wire. It's chunkier than blue/brown because it is intended to carry a heavier load than anything that uses blue/brown.

I'm not an electrician, and my advice is to consult somebody that's qualified to give you advice. However, from my (limited) experience with this sort of thing, the blue/brown insulated single-core wiring is for lighting circuits. Lighting circuits carry a far lighter (no pun intended) load than ringmain. That's why the circuit breakers trip at different loads.

If you have used lighting wiring for the ringmain circuit, pull the breakers immediately. That wiring needs to be replaced.
posted by veedubya at 3:24 AM on October 5, 2005

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