Any electricians here? My ceiling rose and light pendant seem to be "live".

[carbriana]

We've recently had a room re-plastered and painted. The plasterers had loosened the ceiling rose, so now that the painting is finished we have screwed it back into the ceiling. Obviously the original holes had been plastered over, but we drilled some more in what must have been the same place. The problem is, after fixing the rose to the ceiling we've tested it with a Voltage Detector and the whole thing seems to be "live", including the plastic rose and the glass bulb (see photo), although we've touched them and haven't been electrocuted, so possibly it is a false reading. We didn't test it beforehand, so don't know if it was indicating live before we screwed it to the ceiling, but we've tested some of the other pendant installations in the house with the same device and they're not giving the same reading. Are there any electricians out there who could tell me how worried I should be and what to do about it? (I'd contact a Real Life electrician, but it's Saturday night).

Have any wires been disconnected at any point? Does it still light up when the circuit is turned off at the main fuse box?
Normally if the light is wired loop at the ceiling it would have 240v all the time in the rose. But if the switch was in the neutral instead of live it would work but wouldn't be as safe as it should be.
I'd advise having the whole circuit checked for polarity and correct connection by an electrician.

Thanks johnd2. To answer your questions, we're not aware of any wires being disconnected recently, but the pendant was replaced by an electrician about a year ago so would have been disconnected then. I may call him on Monday so he can come back and check it out.

When the circuit is switched off at the fuse box the light doesn't switch on. Does that rule out the theory of the switch being wired into neutral?

That suggests the polarity is correct at the consumer unit board, but may be wrong at the switch. I would expect the electrician to check if they are doing tests, but I'm sure not all would for a simple replacement.

I should also add that those volt sticks are not totally accurate, they just measure a difference between your body and whatever you're waving the wand at. So in the general case it's very possible that you're picking up a signal from other live wires and the stick is picking up an earth or neutral.
The electrician will have proper test equipment to get an accurate answer, which may be that there's no issue at all.

Thanks john. That's useful.

@johnd2 (or anyone), I've had an electrician here today, looking at the ceiling rose. It was the same electrician who I think fitted the rose last year - I had a few done at the same time and I'm pretty sure this one of them, but could be wrong.

Anyway, his voltage detector gave the same reading as mine. He investigated and concluded that the rose is wired "the wrong way round", so it shouldn't work, but it does, and he's not sure why. (He also doesn't think it was him that wired it - he wondered if the plasterers may have re-wired it when they did the ceiling). He then spent a long time fiddling with it but then gave up, saying he was baffled and I'd have to try someone else.

He checked the switch too - he says it doesn't have a "neutral", but it's correctly wired.

I've posted a photograph of the ceiling rose wiring, in case anyone here can offer any further advice. In the meantime I'll be trying to find another electrician with a bit more experience of diagnosing problems.

"He checked the switch too - he says it doesn't have a "neutral", but it's correctly wired"

In the UK it is quite normal, and correct, for a lightswitch to have no neutral. It should have an earthwire, though.

it is also quite normal for a lightswitch to be wired a different way, where it does have a neutral, but this is not so common in UK houses.

When looking for an electrician, ask them which Self Certification Scheme they are in, and write it down so you can check later. There are registers such as NICEIC (and a number of others) where qualified people are listed. "Domestic Installer" is the lowest grade.

Advertising websites where people pay to be shown are a poor source, especially if they are disguised as Trusted or Checled listings.

If they act offended, and won't tell you, consider what sort of taxi driver would act offended when you asked if they were licenced.

" the rose is wired "the wrong way round", so it shouldn't work, but it does, and he's not sure why."

As far as I can see, the Pendant flex is not wired in the conventional "correct" way with the blue (neutral) in the same block as the black (neutral) circuit wires. This is rather eccentric if an electrician fitted it.

He's done the same with the switch wires. Again very unusual.

It will of course work because electricity doesn't care what the colours are.

But it is less safe because people might be expecting the colours to be conventional. Skilled electricians don't trust colours to be right so they check everything for safe.

It is certainly less safe if you have screw-in lightbulbs, because they are supposed to be fitted so the "tip" is live, which you are much less likely to touch with a finger than the "collar" when changing the bulb.

I'd just test them and swap them round, and a competent person would sort it for you. Get them to look at other lamp fittings as well.

It's Difficult to work out all the connections there but it looks like there are banks of 3 connections so

Far right a red wire is directly connected to the live brown.
If this red wire is live then the rose is wired wrong as the the pendant is normally wired to the switched live.

On the far left you have a blue and red and another red wrapped on blue tape.

It is hard to see if where black wires go but it looks like one goes to the middle of tge connections.

Normally what you d expect to see is

1. both black wires and you blue wire together. This is the neutral connection to you rose plus a connection to the next room light 2 ) 3 red wires together. This is your incoming live the live for the next room and tge cable going to the switch

3 a black wire with brown or red tape on it, connexted with the brown of you rose. This is the wire coming back from the switch or. Switched live.

Suprised your electrician couldnt sort it so maybe it is more conplicated than it seems.
It is possible that the installer used a black as a live and the returning red is a switched live.

In theory you could just rewire it. It may be that blue and brown on your rose are just tge wrong way around. To be sure you need to work out which red cable is live with the switch off. Using your pen or a multimeter on the screw terminal and earth.

Yes you need a better electrician, there are obvious things incorrect with the wiring, he would be able to disconnect and test them all to identify them.
Also the cord grip is dislodged and the drop wires should be twisted around the hook really.