Live plumbing?

[matthew.larkin]

No, its a central heating radiator, just nice and shiny. I suppose a neater way would be to connect the earth behind the plasterboard instead.

Matt

[dom]

Do you have your own electricity meter and pay bills directly to the electricity company?

Or are you on a landlord's sub-meter and pay the bills to him?

I think I can see a couple of ways it could be done - but it requires being having a deranged disregard for safety and/or illegally interfering with the suppliers equipment.

[Jim Alexander]

I'd like to have seen what tests the electrician actually did, cos I'm a bit sceptical. If your earth got live then N-E would look like reverse polarity. Read my earlier post again and think about getting another electrician. Specifically ask for your main and supplementary bonding to be checked.

Jim A

[David Hansen]

On Tue, 21 Aug 2007 15:32:07 -0000 someone who may be [e-mail] wrote this:-

Are the central heating pipes that connect to it plastic, or copper? What sort of pipe is under the floor?

[warrenbbs]

EDF, something to do with the way upstairs flat is wired

Hi Jim

Actually an independent electrician and the one from EDF Energy (our electricity board) told me it was reverse polarity (checked at the consumer unit) - they also tested at sockets. Neither of them could believe it at first, but they checked & re-checked several times. EDF disconnecting the upstairs supply (taking out the cartridge from their main fuse) has fixed the problem for me. There was some "DIY" cabling from the upstairs pre-pay meter through trunking to their flat that appeared to be the cause. Right now I'm happy to be able to approach the bathroom, even though I'm doing it with a voltmeter and multi- tester in hand for the time being!

Cheers Warren

[meow2222]

According to EDF, something to do with the way upstairs flat is wired

I cant think of any way that de-energising another supply could solve your problem. Sure it may stop the tap being live, but certainly wont make it safe.

The information we're getting back does sound muddled.

NT

[meow2222]

Of course. One option is a radiator clamp fitted so that nearly all of it is behind the rad, with just the edge of the clip on the front. Another is to bond to the pipe leading to the rad, but thats only doable depending on the type of pipe and connection.

AFAIK there is no requirement to retrofit equi bathroom bonding anyhow, but its a simple approach to your problem.

NT

[John Rumm]

Oh, depending on the type of earthing system you have that could certainly cause problems... (If you have what they call PME, then it means all the equipotential bonded or earthed metalwork in the house would have been tied to mains voltage!).

There are various issues with "old" wiring that can suggest rewires - just being old in itself is not necessarily a primary cause. If the cable is old rubber insulated stuff, then that is usually terminal by now - the insulation will start to crumble and breakdown. The other issue is that older wiring will often not be that appropriate for modern usage patterns - typically far too few sockets etc where you need them. You may also lack many of the safety features that a modern install would have (and would potentially have alerted you to the problem you experienced sooner).

[John Rumm]

The neater way is to bond the pipes in and out (assuming they are conductive) under the floor or in some other non visible place. There is no requirement for the rad itself to have an earth clamp on it. The EQ bonding can even be in an adjacent room if that makes more sense for the pipe layout.

If you have a dual fuel one (i.e. one with an electric element as well as the CH pipes) then having the earth wire on the electric element correctly connected to both the circuit earth and also the equipotential zone in the bathroom would also remove the need for separate bonding.

[John Rumm]

Depends on the earthing system.

Perhaps the OP could read:

tell us what he has.

[Dave Plowman (News)]

But surely PME terminals are only fitted by the 'leccy board and even they wouldn't make such a basic mistake? Also pretty well any house will have some form of local 'earth' too - so a PME wrong connection would cause current to flow at all times if not worse?

[Jim Alexander]

Perhaps, but that's not my point as there is at least a suspicion of dodgy earthing. Read my words again carefully.

The OP takes comfort from the diagnosis of L-N reversal but his description is not a supplier L-N reversal because it seemingly was cured (only) by disconnecting the adjacent flat and a premises L-N wiring reversal would not cause the taps to become live in the absence of a second fault somewhere.

I would have hoped that one of the two qualified? electricians would have helped the OP there. I have no idea whether my theory is right or not but it fits the circumstances.

Jim A

[John Rumm]

Can happen. I have sees head ends wired with reversed colours (although correct polarity) enough times.

It may not - properties with incoming plastic services and no RCD could exist in that state for some time. If the impedance of the connection to true local earth is high then you would not pass sufficient current to trip ordinary (i.e. non RCD) protective devices.

[John Rumm]

My reading comprehension is not usually too bad on the first pass thanks! ;-)

Many things are possible here, and we will probably never know exactly what was wrong. Dodgy earthing somewhere is indeed a possibility. I was just highlighting one way in which apparently live metalwork could come about, since there were a number of posts (not yours) that seemed a little too confident in proclaiming that the supply reversal would not explain the problem.