Ring main and isolation query.

[Jonnyh2404]

Left / right is common these days now that ground floors are typically not suspended timber. The CU should be labelled left/right, not up/down though.

However, should you have received a shock through relying on labelling and not proving dead, you would be just as much in the wrong as the chap who labelled the CU.

I think you've all missed my point. The CU is labelled up lights, up sockets, down lights, down sockets, cooker. Downstairs isn't left and right either. Upstairs sockets isolates all sockets apart from master bedroom and a spare bedroom. Then when I switch downstairs sockets, all downstairs sockets plus the master and spare bedroom isolate. In other words it looks like a complete hash

 

[charliegolf]

My house is 20 years old, and has labels such as, 'sockets 1', 'sockets 2' etc. I just spent an hour with a small lamp, going round working out exactly what rooms and corridors are on which mcb. I stuck that on the cu enclosure. When I touch a socket, I plug the lamp in, put it on and then turn the power off. I assume that's belt n braces?

 

[JohnW2]

I think you've all missed my point....

I can't speak for others, but I don't think I've missed anything.

The CU is labelled up lights, up sockets, down lights, down sockets, cooker. Downstairs isn't left and right either. Upstairs sockets isolates all sockets apart from master bedroom and a spare bedroom. Then when I switch downstairs sockets, all downstairs sockets plus the master and spare bedroom isolate.

Indeed - that's what you said (very clearly) at the start, so I doubt that anyone has misunderstood that.

In other words it looks like a complete hash

As I and others have said, it's a bit messy, but not all that unusual. The important thing is that, no matter how the circuits are arranged, the CU should be labelled clearly to reflect the arrangement. In other words, yours should be labelled something like "Upstairs sockets other than master+spare bedrooms" and "Downstairs sockets plus master+spare bedroom sockets".

As I said at the start, it's naughty that your CU is not labelled clearly and, as has now been confirmed, it is also a violation of the regulations not the identify the circuits adequately. If you want to complain to those responsible, I think that's the only thing you could definitely complain about.

Kind Regards, John

 

[ban-all-sheds]

I think you've all missed my point.

I can't speak for others, but I don't think I've missed anything.

Nor I.

In other words it looks like a complete hash

To reiterate what others have said, there's nothing wrong with where your circuits run or which sockets they serve. The only thing wrong is the labelling.

 

[ban-all-sheds]

I assume that's belt n braces?

No - it's just belt. Or braces.

The way to use a lamp like that (or a radio if you are on your own and can't see the socket, or don't want a lot of schlepping back and forth) is:

1. Power on, plug the lamp in, see that it lights up.
2. Power off, see that the lamp goes off.
3. Power on, see that the lamp lights up. This is to ensure that you have got the right MCB, and that it wasn't the case that the lamp coincidentally failed at just the time you switched the wrong MCB.
4. Power off.

But better to equip yourself with these:

 

[Lectrician]

I think you've all missed my point. The CU is labelled up lights, up sockets, down lights, down sockets, cooker. Downstairs isn't left and right either. Upstairs sockets isolates all sockets apart from master bedroom and a spare bedroom. Then when I switch downstairs sockets, all downstairs sockets plus the master and spare bedroom isolate. In other words it looks like a complete hash

I personally think you are making a big deal over this - there is nothing wrong with it other than poor labelling.

 

[John D v2.0]

I'm sure someone on here had two phase in the same accessory, they were coming from different dbs let alone different circuits.
I think after a lot of debate it was decided that even labelling it was not required by the regs!

 

[JohnW2]

I'm sure someone on here had two phase in the same accessory, they were coming from different dbs let alone different circuits.

I don't think I've ever mentioned it here, but I had a few of them when I moved into this house. The three phases are essentially split onto three floors, which means that two-way switching of hall/landing lights brings the 'wrong phase' to a floor, and there were at least a couple of cases in which this happened in 2- or 3-gang switch which also had 'right phase' (for the floor) in it.

I suppose it's not all that much worse than having a similar switching arrangement with a single-phase supply, since there are (usually) still two circuits which need to be isolated to make the accessory entirely dead. However, the two circuits to be isolated are then (usually) in the same CU/DB and I was a little more concerned by the fact that people would have to realise the need to isolate at two different CUs/DBs.

To address that concern, I could just have separated the circuits/phases into separate accessories but eventually decided on the more complicated solution of using 12V relay switching, thereby keeping all phases restricted to their own floors.

I think after a lot of debate it was decided that even labelling it was not required by the regs!

Hving just had a quick look, I think you're probably right. There is a requirement for a label if an enclosure contains voltage(s) >230V relative to earth, but no requirement I can see in relation to'between-conductors' (e.g. phase-to-phase) voltages >230V.

Kind Regards, John

 

[ericmark]

I never actually thought about it before, but the installation certificate should be with the consumer unit, so it is possible the installation certificate does fully identify circuits, however the labels used on the consumer unit are the standard issued ones with consumer unit just giving a quick reference to if lights or sockets.

The Martindale proving unit I found useless as it only gives out 500 volt, so one could get a faulty tester which will only light with 500 volt and not with 230 volt, unlikely I know but the whole idea of a proving unit is to prove the tester works, other makes like the Kewtech have a ram up and step down so will show if the 12 volt lamp will only light with 500 volt, Megger also rams up and down with lights to show the voltage being tested.

And even with the best testers they can't stop it being re-energised after the test has been completed, I had it once with a concrete batching plant, a new plant had replaced the old one, but cables had not been removed, it was my job to remove them, I found a junction box which the old electrician identified as being part of old plant, no lid on the box and open terminals so one would hope it was dead, however just in case I tested every cable, before starting to saw off the cables and remove them.

I left to have my dinner and got called back with reports one cable was sparking, it transpired it feed an augur which was still in use and had not been replace when new batching plant was installed, this was auto switched on by the PLC running the batcher. So there was no way any testing for dead would have found this, after that near miss cables were only removed when the batching plant was not running.

The same applies with a domestic house with items like the central heating, cables supplying motorised valves may only be energised when there is a call for heat. This is why I still use a neon screwdriver, not to test for dead, but to alert if power should get switched on again. With high voltage not only do we prove dead we also ground the cables so they can't become live latter. However we rarely go to those lengths with the low voltage used in a house.

 

[333rocky333]

When part P first came out wasnt it in 2 parts, one regarding things like labelling etc to ensure safe maintenance etc

 

[flameport]

Yes, the other part was:
P2: Sufficient information shall be provided so that persons wishing to operate, maintain or alter an electrical installation can do so with reasonable safety.

 

[ban-all-sheds]

And not only that, P1 was more extensive, and was later reduced in an unfortunate way.