Lighting circuit

[tabbypurr]

the meaning of that is not clear

and that is making nonsense up.

NT

[tabbypurr]

I've just fitted new ones, they aren't that way. I think you have to pay tu ppence extra for that.

NT

[tabbypurr]

some of it, I needed to get upto speed on the changes, not that it's relevant

I just fitted new ones that don't have that feature, they're still allowed

they have. The point was that you're convinced it's necessary.

Yet again, decades of experience of all types of light fittings on unearthed circuits shows otherwise. It was wholly reasonable to insist on earths when disintegrating rubber wiring was common, today it's not like that.

I wouldn't choose to leave the chandeliers I had years ago unearthed. That's all historic equipment though, not modern regs compliant.

That's unrealistic. Lots of people come up with lots of ideas to save money. Some work out, some don't. It's one of the major drivers of improvement of quality of life.

NT

[tabbypurr]

not the most convincing of points. Try again.

[tabbypurr]

If you think all BR must be followed in order to have a safe effective house, there's an awful lot you don't know.

NT

[tabbypurr]

either give us a page or don't

both occur. Are you claiming to not be aware of this?

that must have come from a thread here as I don't have the info at my end.

which has been given already

that's a choice for each builder & electrician, depending on how often that happens for them

NT

[John Rumm]

Indeed I am, as are many informed people. Necessary on two levels - the regulatory; that is what the regs say, so that is what you need to do, but also practically, that you will reduce the number of electrical injuries, and house fires as a result of the measure.

The only justification you seem to be able to produce for this claim is that there is not a substantial death rate directly from electrical installations. However that was also the case in 1966. So why do you suppose the requirement was introduced then?

Rubber wiring was not commonly in use in 1966, and the 14th edition was not going to apply retrospectively.

Ah, realisation dawns.

Does all this historic equipment suddenly vanish, or is it still out there?

Class I fittings are still "regs compliant" anyway, and still freely available for sale. In many cases the quality of the available gear has not improved.

Well lets leave this one shall we. I am sure I am not going to change your mind.

Personally I feel you are flogging a dead horse here. ISTM that using bell wire or similar in mains installations would have negative safety implications, and more importantly end up costing more overall rather than less in real life. It would also make house wiring less easy to adapt and extend.

[John Rumm]

I did not say that so move on.

I asked you to cite a requirement from BS7671 that you believe is now redundant and should be removed.

Now that is true. Its why I keep learning.

[tabbypurr]

the existence of a regulation is not an argument for that regulation to be needed

I've yet to see data that demonstrates that

or that

On the contrary in '66 most wiring in houses was rubber insulated. The chan ge to pvc was at that time recent-ish.

the existence of historic noncompliant equipment is hardly news. It's only refitted in a tiny percentage of cases.

you've not seen the historic light fittings I have then. I'm familiar enoug h with China specials, but many things of the past were much worse.

The latter point is true, but I don't think people for whom 360w per circui t is plenty are likely to start installing excessive lighting levels. 500w halogens are history now. Also as the years roll by lighting power will dro p a lot further as LEDs get much more efficient.

NT

[tabbypurr]

I assume you don't think that, in which case you dont' believe all BR rules are necessary for safety. That was the point being made.

erm... something about lighting earths?

The requirement for 9.5mm clearance from plug pin to plug outer edge is another, albeit from a different BS. It made good sense when pins were unsleeved, now it's redundant.

NT

[John Rumm]

Whether you believe its necessary or not does not matter, you still need to comply with the requirement.

And, at this stage 50 years later you are not going to either...

Are you going to hazard a guess as to why the rules were changed then?

Most *existing* housing stock in '66 may have had at least some rubber.

There would not have been much new rubber going in by that date as PVC had been available for quite number of years at that point.

However its a moot point, since new rubber insulated cable does not have any of the failings that we associate with it now (i.e. its not installed in its "disintegrating" state). So rubber insulation alone would not have been a justification for adding a CPC to lighting circuits.

From the mid 50s

That will be mostly true, but its not not a justification for a lower spec of cable than 1.00 mm^2 T&E IMHO, since that is really the minimum you need for adequate robustness to survive both installation and use.

Class I fittings will remain, so the CPC must also be retained.

The trend for ever better insulated and more air tight housing will increase the requirements for forced ventilation. Combine that with the rules on bathroom electrics, and it still makes the lighting circuit the ideal to take power for things like extractors and shaver sockets. So extra capacity on lighting circuits is not a bad thing.

Lastly from an installers point of view, having to carry yet another size of cable is just more hassle and more money tied up in stock. (some electricians don't even keep 1.0mm^2 in stock, and opt for 1.5 as their minimum).

[John Rumm]

I would have said so if I did.

You flip from the specific to the general as if that in some way supports the specific.

For example Part P is a BR "rule" that I believe has little or no benefit for safety. Earthing lighting circuits however I feel was a very worthwhile rule change. The fact that I don't believe part P is a good idea, does not change my opinion on lighting circuits.

Can you find anyone else to support the idea that we should go back to unearthed lighting circuits?

Pin clearances are also intended to make it impossible to plug the earth in upside down, thus opening the shutters. (a reason many 4 way extension leads are not actually compliant)

[tabbypurr]

that is not relevant

It's a moot point. I don't have any difficulty in believing it was down to the widespread existence of disintegrating rubber cable insulation with con sequent hazard, a situation that has vanished today never to return. But it 's moot.

sure it was. The experience with pvc & polythene insulated cables was at th at time limited to a decade or so, no-one knew how the cables would survive long term. So precaution againt the widespread serious problem of disinteg rating cable looked highly realistic at that time.

Lots of houses have had low voltage (ie not mains) wiring installed with mu ch thinner conductors out of reach that has proven reliable over time.

I'm sure you're already familiar with why that is a nonsequitur.

Sure. Extractor fans are in the region of 20w or so, running part of the ti me. Shaver sockets ditto, with some running 24/7 charging toothbrushes. Tho se have no difficulty running on a 360w circuit.

Some see it that way. The reality though is that lots choose to install bel lwire in situations where they could have used 1mm or 1.5mm^2 T&E.

NT

[tabbypurr]

No. But really I think this has been explained more than once already.

I've not looked. Years ago I did find one person that talked of going back to bare iron wire buried in plaster. I looked at that & concluded it was not safe or energy efficient.

it simply does not do that. I'm talking about the required distance from the plug pin to the outer edge of the plastic plug.

And afaik people trying to open shutters to stick bare wires in is another issue relegated to the history books, at least in this country.

NT

[Steve Walker]

But if you can't do that, how can you plug your shaver in in an emergency? ;)

SteveW

[dennis]

Doesn't help much though. You still can't see where you want to.

[tabbypurr]

it's standard practice to have at least 2 lighting circuits, idea being the house/flat doesn't descend into complete darkness.

NT