How many lighting circuits?

On 21 May 2004 08:21:24 -0700, in uk.d-i-y snipped-for-privacy@lineone.net (David) strung together this:

However you like.

Where they are. Split them down the middle, either front to back or side to side, it makes no odds really.

Depends on what you want to achieve. I generally use the loop in method for a standard no frills lighting circuit.

Wherever you want, as long as there not buried in the plaster!

might be worth bearing in mind that when a bulb fails it's inclined to trip an mcb, so, you would then rely on the circuit that's still live - plan accordingly so that you've got at least 'borrowed light' to find your way to the fuse-board. Hugh

I'd try to arrange them so that if one circuit trips, you still get some lighting from lights on another circuit - ie bedrooms on a different circuit to the hall that connects them.

Bob

Personally, whether a house or a bungalow, I prefer random allocation between lighting circuits. The idea of multiple lighting circuits is to ensure that some lights are available in the event that an MCB blows (except when there are loads of fittings and division is required for electrical reasons).

I'd rather have some lights on every floor working. The only disadvantages are that it requires more cable and some cretin might get confused and only turn off one circuit by assuming there is a up/down split.

The methods are basically the same. The loop-in just means that you use the junction box that is integrated into the light fitting. It is best to use loop-in when possible, as you maintain easy access to the junction box for inspection of the screw terminals.

Not near the ceiling rose, as the ceiling rose has a built in junction box that is easily accessed, so you'd just be doing a loop-in circuit without the advantage of easy access. Junction boxes are required either when it is convenient to have the junction box remote from the light fitting (for example, an external light, or multiple fittings on a single switch) or when the light fitting does not have an internal junction box.

Ensure you don't wire any loops into the circuit, by running neutrals and lives in different paths or using the old style strapping system for 2 way lighting. These interfere with hearing aids. If all cables are T&E and run in a tree like formation with no loops at all for any reason, then fundamentally this has been achieved.

Christian.

Contemplation fodder:

Any room with 2 light fitings can be supplied from both lighting circuits. When one pops you dont lose light then.

If this is done the CU should be marked clearly to indicate this, you dont want someone frying themselves.

MCBs cause nuisance trips on light circuits, and this is a risk factor. Fuses or type C MCBs would eliminate this problem.

RCDs on light circuits may well cause more deaths than they prevent.

Under regs youre required to have a certain amount of energy efficient fittings. They make good sense in every way, but there are a couple of pitfalls with them to beware of. Avoid the common mistakes and they will make life easier safer and cheaper.

Regards, NT

That's building regulations as opposed to the IEE wiring regulations. Why not tell us what those "couple of pitfalls" are?

The fact that they are hideously ugly, huge and expensive. I only use compact fluorescent bulbs in my house, but I would not have one of those dedicated energy saving fittings near my property.

Christian.

I should add, that rather than mandating ridiculous non-standard fittings, they should stop attempting to ban lamp shades and just put a 5 pound tax on incandescent light bulbs.

Christian.

eh, Ban lampshades?

-- troubleinstore

The "official" energy saving fittings are about twice the size of a standard bayonet, so lamp shades don't fit.

Christian.

A better idea would be to forget the whole silly idea of mandating energy saving bulbs and fittings altogether, since it is largely political window dressing.

Let those that want to have them buy them and those who don't buy what they want.

Personally I wouldn't have an CFL lamp at all indoors because I find the light sickly.

Fortunately, I don't see anybody taxing incandescent bulbs any time soon.

.andy

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Not at all. Lighting accounts for a large amount of carbon dioxide emissions, because unlike high power appliances, bulbs are on for very long periods. If all incandescent bulbs in the country were replaced by CFL types, then we would reduce CO2 emissions greatly, as well as saving money. I'd rather suffer slight degradation in light quality than be under 20m of water when sea level rises, or enter a UK specific ice age when the Gulf Stream fails.

OK, provided they plant enough additional trees in their gardens to absorb the carbon dioxide they avoidably emit.

Christian.

IMO, energy conservation is the biggest red herring ever - and a total waste of money.

Even if you reduce fossil fuel usage by 50% (probably an impossible goal), all that will happen is that it all gets used up in 200 years instead of 100 (or whatever the current estimate is). In other words, it's all going into the atmosphere anyway, so why worry about how long it takes to do it.

As for the results of all this CO2 - climate changes all the time. Some areas become wetter, some drier, some cooler, some hotter. The change caused by CO2 emissions is not certain to be a bad thing. After all, this CO2 was all in the atmosphere millions of years ago, and it didn't do the planet any harm then. In fact, I expect plants to respond by growing bigger, faster - counteracting it somewhat.

It is the fingers in ears approach that will lead to environmental destruction.

La la la la la la.

The problem is not that we are running out of fossil fuels, the problem is that we keep finding more of the filth. That is the bad thing. What we need is a good shortage of the stuff now, so that it becauses finanicial advantageous to find alternatives.

Christian.

It's not fingers in ears - it's about being able to see further than the green propaganda, and realising that it's all going to be dug up and burnt whatever happens. Trying to stop that happening is futile - preparing to deal with the consequences (and even those are not certain) is what needs attention.

You have a point that we are finding more or the stuff, so the predictions from the past that we will run out in 30 years were wrong, but how much more can there really be? And even if there was 10 times as much as predicted, it's still all going up in smoke.

Bob

I don't think I buy that If you take a typical house, I reckon that the consumption of electricity or natural gas for heating purposes is probably in the range of 10-20 times that of even incandescent lights.

Added to which, if there were more than political tokenism in it, the Building Regulations would mandate that CFL fittings and bulbs or equivalent are used for all lights in new buildings and when wiring is replaced. They are not because the government knows that they wouldn't get away with it and people would rip them out.

It's not very likely to happen and even if it were, it is not high on the pecking order of energy consumption in comparison with other uses.

The trouble is that it isn't a slight degradation. The light from these things is sickly and bilious IME, and the bulbs are plug ugly.

The "whens" about sea level rise and ice ages are "ifs" at this point.

That isn't to say that saving energy isn't a good thing. It is. However, it should be in the correct context and priority and not because the government wants to look good at some conference.

That probably isn't that many if related to lighting use.

.andy

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So, you think it is all hopeless and everything is lost, so there's no reason to do anything about it?

Hopefully, the oil price will continue to rise. I think that financial imperatives are the most likely stimulus to the development of alternative fuels.

Christian.

Actually I think we'll run out of fossil fuels before it's all been dug up - there must be a point where it's not economically viable (more energy / cash in than out). I think that's already the case with some of the US oilfields.

I've always managed to save considerably by replacing all bulbs with CFL. If you average 200W lightbulb consumption over the course of the year, you use

Try more recent designs. I use the GE mini-tech ones, which aren't much bigger than incandescent bulbs and give yellow light. Most people don't even believe they are CFL until they are looked at closely.

Christian.