- Joined
- 17 Aug 2010
- Messages
- 2,741
- Reaction score
- 453
- Country
They still sell ones with two output sockets and a bulb holder in home depot.
Socket for vacuum cleaner from lighting circuit?!
- Thread starter JohnW2
- Start date
Sponsored Links
Indeed, we all go mad in earthing and bonding to the nth degree as a matter of safety and quite rightly too.
However in some conditions it can actually cause a reasonably "safer" situation to become far more dangerous.
Example - the case of Mary Wherry, the situation might have been risky for quite a while but at that particular time if she happened to touch a earthed appliance the fatality occurred.
If we could live in an all insulated world it could be a safer place.
Exactly, there is always a balance to be struck. In most cases, earthing things will, indeed, 'on balance' be the safer option, but 'unnecessary' earthing can easily have the reverse effect. For example, some people might feel that to earth an outer touchable conductive part of a Class II item is a good (and, they think, 'harmless') idea, as a 'belt and braces' measure in case the 'double insulation' were to totally 'fail'. However, as EFLI frequently punts out, 'on balance' such 'unnecessary' earthing actually creates more of a potential hazard than it protects against.
Very true. If supplies were not earth-referenced (i.e. if they were 'floating'), then everyone would be safer and 'earthing' would be an irrelevant concept. However, I imagine that it was decided that there was no way one could guarantee an absence of an 'incidental' earthing of one side of the supply, so better to 'pre-empt' that by deliberately earthing one side? Or was there some other reason - I just don't know?
Kind Regards, John
From my cellar .... one light bulb (no argument about the word back in those days
) PLUS 3 x 2-pin outlets (one hidden behind, and one a B22 'plug' fed from a single B22 lampholder ... and I've seen worse 'Christmas Trees' than that, hanging from lamp holders, in my time
Kind Regards, John
Sponsored Links
Agreed,
Incidental Earthing and Deliberate Earthing puts us in the mode of needing Earthing .
As you rightly say, necessary earthing is fine but unnecessary earthing can increase danger.
If double insulation etc is of a reliable quality then great.
Incidental Earthing and Deliberate Earthing puts us in the mode of needing Earthing .
As you rightly say, necessary earthing is fine but unnecessary earthing can increase danger.
If double insulation etc is of a reliable quality then great.
Quite so.
It's obviously impractical in retrospect but if, from the very outset, extraneous-c-ps (i.e. anything connected to earth) entering buildings had been 'banned', then (give or take bernard's discussions about damp walls and floors), there would have been no need for anything inside buildings to be earthed, even if the supply were earth-referenced - and, indeed, any such 'earthing' of anything would itself have been 'banned', because it would represent an unnecessary hazard.
However, even if that had been done, there would still have been a big problem 'outdoors' - since there is necessarily plenty of 'earth' there!
... so we're stuck with what we have
Kind Regards, John
Welcome to the forum.
I'm not sure what you are referring to - if the photo I recently posted (of what my grandparents used to use, 60+ years ago), then that doesn't surprise me, but in a few decades' time, people in the UK will probably regard it in the same way as those in the UK do today!
EICRs are undertaken with reference to the current version of the regs (BS7671) (whether one regards those regs as 'wrong' or not
) which explicitly say that BS1363 sockets may be installed on 'lighting circuits' and also allow flexible cable to be used for fixed wiring. Hence, an EICR could only find fault with that arrangement if the flex was not of an adequate size or, possibly (if the flex actually is connected to the terminals of the ceiling rose) on the basis of the ceiling rose terminals not having a high enough 'current rating'.Kind Regardsm, John
Agreed, indeed another problem arises because the earth itself is not very conductive per unit part .
Imagine that it is composed of very small conductive balls and each ball itself is highly resistive.
Each of these small conductive balls is in contact with a few more.
That has the effect that locally it sets of being quite a high resistance/impedance and as we move our test rods/probes away then, exponentially the resistance drops lower because the amount of parallel resistances increases until it becomes very highly conductive to the end of the universe (well to the other side of the world).
If we lived on a massive conductive plate of say copper for example then we would not encounter as many problems of bolting it down to one earth polarity.
Compare it to the length or breadth of a human or the wheelbase of a cow etc and we have some big problems of being conductive but not highly conductive.
So we deliberately earth or bond somethings together to assist in equalising conductivity.
But it still means that our incoming earth supply reference could be several volts adrift from the earth reference beneath our feet just because those refence points are actually a few tens of metres away from each other.
We could stop calling them lighting citcuits.
Agreed,
Radial circuits or ring final circuits.
They are all for power (mains power usually).
So "circuits with some lights on and maybe other things" could be one description and " circuits for appliances and other things" could be another description.
At present, a circuit with only fans on might be described as a "fan circuit" but a "circuit with mainly lights on but perhaps a small fan or two" would mostly be regarded as a lighting circuit.
See where I`m going?
Radial circuits or ring final circuits.
They are all for power (mains power usually).
So "circuits with some lights on and maybe other things" could be one description and " circuits for appliances and other things" could be another description.
At present, a circuit with only fans on might be described as a "fan circuit" but a "circuit with mainly lights on but perhaps a small fan or two" would mostly be regarded as a lighting circuit.
See where I`m going?
I wonder if we refered to them as X circuits (x representing the fuse or breaker nominal rating) might be more helpful?
The trouble in the UK is that a 16A cable (more fashionably 20A lately) is for some reason protected by a 6A OPD and called a lighting circuit.
Admittedly it has lights on it but, as you say there are plenty of other things that get connected to it some of which cause consternation to some.
The labels merely listing what is connected; not offering a name for the circuit.
Why is the OPD still 6A? Why not just treat it as a 16A radial for whatever? Surely the oft mentioned "but light roses and switches are only 6A" does not make any difference (installed correctly); no one complains that sockets are only 13A yet on 32A circuits.
Incidentally, here in my flat the 'socket' circuit and the 'light' circuit are exactly the same - 16A.
Since moving I have realise that the UK is very traditional (being polite) in that some things that used to be done for a reason are still done without thought although the reason no longer exists - and, of course, it is thought to be better than the way anyone else does it regardless.
Admittedly it has lights on it but, as you say there are plenty of other things that get connected to it some of which cause consternation to some.
The labels merely listing what is connected; not offering a name for the circuit.
Why is the OPD still 6A? Why not just treat it as a 16A radial for whatever? Surely the oft mentioned "but light roses and switches are only 6A" does not make any difference (installed correctly); no one complains that sockets are only 13A yet on 32A circuits.
Incidentally, here in my flat the 'socket' circuit and the 'light' circuit are exactly the same - 16A.
Since moving I have realise that the UK is very traditional (being polite) in that some things that used to be done for a reason are still done without thought although the reason no longer exists - and, of course, it is thought to be better than the way anyone else does it regardless.
The lighting circuits were usually wired in 1.5mm, whereas 1.0mm was adequate, the reason usually given that the 1.5mm was physically more robust. 6amp was adequate for most domestic premises, but for commercial premises, that could be upped to 16amps.
We could.
However, goodness knows why I am 'defending' him, but I don't think our absent friend's concerns relates to what the circuit is called. I think his concern relates to "a 13A socket being fed from a 6A circuit which also supplies lights (particularly in a loft)".
I don';t think any of us could deny the truth of the theoretical hazard which concerns him. However, I think that most of us feel that any risk (of someone plugging in high-powered load into a socket in a loft) is extremely small, particularly if the socket is appropriately labelled and that, even if 'the worst' were to happen (loft 'plunged into darkness') the probability is low that anyone would come to significant harm as a result.
I also suspect (but obviously do not know) that he might be far less concerned about what we are discussing here than the situation 'in s loft'. Even if the situation is 'as it appears', and even if the circuit is a 6A one (which I doubt), it is incredibly unlikley that anyone would come to any harm as a result of a hotel restaurant (with an essentially 'glass wall', and also with emergency lighting) were to be 'plunged into darkness.
Kind Regards, John
What about my other point of why does the circuit have to (still ?) have a 6A OPD?
Does this also (like rings) go back to BS3036 fuses where a 15A fuse would have to have had a 21A CCC cable?
Therefore they chose 5A with small cable as it was adequate for lighting - so that is what is still (unthinkingly) done.
Does this also (like rings) go back to BS3036 fuses where a 15A fuse would have to have had a 21A CCC cable?
Therefore they chose 5A with small cable as it was adequate for lighting - so that is what is still (unthinkingly) done.
DIYnot Local
Staff member
If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Are you a trade or supplier? You can create your listing free at DIYnot Local
Sponsored Links
