Triple and earth for two way lights, does it mater which colour?

[ericmark]

In the main it seems grey is separated from brown and black by the earth, so the capacitive and inductive link to grey is less than between brown and black, if L1 is permanent line then L2 is switched line, and Com will alternate with switch positions, so it would seem grey should be switched line so it picks up less capacitive and inductive power, brown permanent line as furthest from grey so black goes to Com.

OK in theory, but in practice is this the case, and if not correct order does it make bulbs glow?

 

[Taylortwocities]

does it make bulbs glow?

Bulbs don't glow, they grow.

 

[JohnW2]

In the main it seems grey is separated from brown and black by the earth, so the capacitive and inductive link to grey is less than between brown and black, if L1 is permanent line then L2 is switched line, and Com will alternate with switch positions, so it would seem grey should be switched line so it picks up less capacitive and inductive power, brown permanent line as furthest from grey so black goes to Com. ... OK in theory, but in practice is this the case, and if not correct order does it make bulbs glow?

As you say, it's all very theoretical (and probably only of relevance for long cable runs) but ...

... (not having thought about this too deeply, so maybe wrong!) I would have thought that, if one was wanting to be 'as careful as possible' (and with either the traditional/old or 'modern' way of 2-way switch wiring), the grey should be the conductor connected to the lamp/bulb - to 'distance' it as much as possible from the other two conductors (either of which could be 'live' when the lamp/bulb was meant to be off).

Kind Regards, John

 

[EFLImpudence]

Isn't that what Eric said?

 

[JohnW2]

Isn't that what Eric said?

It probably was, but I was attempting to present simpler/clearer reasoning, since I was a bit confused by ...

.... if L1 is permanent line then L2 is switched line, and Com will alternate with switch positions ...

Kind Regards, John

 

[ericmark]

So you agree the grey (assuming that is the one on it's own separated by earth should always connect to the bulbous device which emits light (bulb for short) and not to the bulbous unit containing nourishment waiting to take advantage of spring weather (bulb for short).

Although there is a move away from replaceable tubes and bulbs in lamps, so today we do replace the whole lamp or lumenair, however I find the word "bulb" does separate the word for whole unit and device within the unit well, although in this case I can see how I should have called it a lamp as I was talking about the whole unit.

I remember as a young guy not long out of my apprenticeship working in Algeria ordering 2 head lamps, and I got two head lamps, minus the bulbs, not made that mistake again, it is of course historic, the spigot was on the wall or car or railway engine and the lamp be it carbide, oil or gas fitted on the spigot and when electric came along the electric bit which replaced the wick or mantel was bulbous in shape so was called a bulb.

I am sure one could find another name for a tube or bulb, clearly not lamp or lumenair as that is name for whole assembly minus the bulb or tube, however I can't think of a word in common use to replace bulb or tube which so well defines the item.

 

[JohnW2]

So you agree the grey (assuming that is the one on it's own separated by earth should always connect to the bulbous device which emits light (bulb for short) and not to the bulbous unit containing nourishment waiting to take advantage of spring weather (bulb for short).

I do. It's the conductor connected to the bulbous device that emits light that one wants to 'distance' from possible sources of induced potential.

Where I slightly disagree with you is that I don't think it makes any different which way around one connects the other two conductors, since (depending on switch positions) either of them could be 'live' when the light-emitting device is meant to not be 'emitting no light.

I remember as a young guy not long out of my apprenticeship working in Algeria ordering 2 head lamps, and I got two head lamps, minus the bulbs, not made that mistake again ...

As I reported once when we were having this terminological discussion, I tried asking in Halfords for 'a lamp for my headlamp' - and got some very funny looks. Similarly, when I asked in Homebase (or was it B&Q?) where I could find their 'lamps', you can guess what part of the store I was directed to!

It seems that this is one of the attempted changes in technical terminology which the general public (and even many in retail, even wholesale, outlets) are, on the whole, simply ignoring!

Kind Regards, John

 

[Notch7]

The term lightbulb, is more common than lightlamp.........

 

[JohnW2]

The term lightbulb, is more common than lightlamp.........

Indeed so - and I would say that is a major understatement!

'Lightbulb', rather than just 'bulb', seems to be the most common word in use (by all but the technical purists). That avoids any confusion )very rarely possible, in context, anyway!) with 'bulbs which grow', and I really don't see why people should have a problem with that. It certainly avoids the silliness inherent in asking for a 'lamp' for one's head lamp, table lamp, standard lamp, reading lamp inspection lamp or whatever!

Kind Regards, John

 

[DetlefSchmitz]

and I really don't see why people should have a problem with that

I suspect they don't - they just like to stir. It worked - didn't it?

 

[JohnW2]

I suspect they don't - they just like to stir. It worked - didn't it?

Yep, and not just in the past tense - it always does 'work'!

I think that in both the cases of 'lamp' and 'low voltage', it is probably the case that 'they' would be best advised to 'give up', since many years have passed without most of the general public (and many others) showing many signs of 'complying' - so that I somewhat doubt that they ever will!

Kind Regards, John

 

[DetlefSchmitz]

Too right.

 

[ericmark]

It seems USA calls 12v and 24v low voltage, so it depends where the items were to be sold as to if called low voltage or extra low voltage.

 

[DetlefSchmitz]

I have never seen anything sold as 'extra low voltage'.

 

[EFLImpudence]

Potterton have a different view -