Thats how i read it at first but it said borrowed/shared neutral
Thats how i read it at first but it said borrowed/shared neutral
Sponsored Links
This is the second time you've said this. I'm not sure what distinction you're making between "borrowed" and "shared" - I wrote "borrowed/shared" words since some people seem to use the terms interchangeably, to mean the same thing.
The important thing in the context of this discussion is surely that we're talking about a situation in which a neutral in one circuit may also carry current from another circuit - whether one calls that "borrowed" or "shared".
Kind Regards, John
Now we know that it was only switched off at a light switch, I agree.
Kind Regards, John
Was the OP not just asking about borrowed neutrals, thinking he would not have got a shock unless it was?
Sponsored Links
That's theoretically true but, as I said, I know the electrical installation of my house well enough to know that there are no such problems.
Other than at the origin of the installation, there is almost nowhere where wiring of one phase gets anywhere near wiring of other phases - in general, each floor only has one phase. The only place where the phases 'come together' is in an enclosure which contains 'phase failure relays' (which provide a little lighting, from another phase, in the event of failure of the floor's phase) - and I was very careful about constructing and (internally) labelling that.
I am certainly sufficiently confident that I would never bother killing the other two phases when I was working on a circuit on the third phase.
Kind Regards, John
He probably was, and that 'took some of us in' (certainly me) - since at the time he asked, he was the only person who knew that he had not switched off the circuit at the CU.
Kind Regards, John
Oh i see i thought you meant borrowed as in neutral for 2 circuits or shared as in shared between other lights on the same circuit, apoligies for the confusion
.....
Oh, I see. Unless (very unusually) each light has its own separate supply from the CU, it is surely inevitable that the lights on one circuit will "share" a neutral path, isn't it?
Anyway, I'm glad if you now understand what I meant!
In any event, this whole discussion has been confused by the fact that at least some of us (not the least myself!) made assumptions about what the OP had done which have proved to be incorrect. The most important lesson is surely that one should never work on a circuit without 'isolating' it at the CU, coupled with the warning that even that may not render it safe (despite satisfactory results of initial 'testing fro dead' procedures) in the presence of a 'borrowed' neutral.
I wonder how many people actually do 'test a neutral for dead' after (carefully!) disconnecting it?
Kind Regards, John
- Joined
- 11 Jan 2004
- Messages
- 42,795
- Reaction score
- 2,648
- Country
I would think that this has been considered over the years, but a different colour could not be agreed upon.
Strange that a decision could not be made. In Australia in the red/black days switch wires were white. Not sure what is used now. In France switch wires are usually purple and a second one (travellers in 2 way switching) is orange.
All seems sensible to me.
Of course not. Ask ten people what colour it should be and you'll probably get eleven different answers
Indeed it does - but in reality only works when using singles. If using T&E or 3C&E you'd need lots of different rolls of cable for the different possibilities - and you may have noticed how few sparks can be bothered to use twin brown T&E for switch drops. Oversleeving other colours doesn't really help with the initial installation thing of identifying multiple cables in a switch back box if they weren't labelled during first fit.
I would not say can't be bothered; I think twin brown is of no benefit and an actual disadvantage.
I imagine that is the case.
For what it's worth, as a purely personal thing, in my own house (or those of "family/friends"), I have always adopted the convention of adding a small bit of yellow sleeving to identify a S/L - usually heat-shrunk over the brown {or black} over-sleeving (when required).
I think I originally arrived at yellow, many years ago, because of the way in which I sometimes used 'old-colours' 3C+E - using red for L, blue (over-sleeved black) for N and the yellow for S/L.
Kind Regards, John
In Australia, the Red/Black days are still with us.
(Please see https://en.wikipedia.org/wiki/Electrical_wiring)
If you look at this you will find that Red (Line) and Black (Neutral) is “permitted” but Brown (Line) and Blue (Neutral) is preferred – for “Building Wiring”
However, no manufacturer in Australia makes TPS Twin and Earth cables with Brown and Blue insulated conductors (they are still Red and Black) and no such cable has ever been imported into Australia.
There is available (and always has been - at least since WWII), TPS two wire cable (without Earth) in which the conductors are insulated with the colours Red and White - for connecting to switches from ceiling lights. (White being a "Switched Live" conductor and Red being the "Live" conductor.)
There is also available "double insulated" TPS sheathed single wire cable, both Red and White insulated. This is because it is NOT ALLOWED in Australia to re-purpose any conductor as something else, simply by slipping a piece of coloured tubing over it's insulation.
(However, the flexible leads and cables now sold here do have insulated conductors of Brown, Blue and Green/Yellow.)
Last edited:
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
