In a lightswitch the wire entering is live but once the switch is turned on so to is the wire leaving. Is it my imagination or was it once the practice to place red (at the time) sleeve on the 'leaving' wire to show that it could also be a live wire?
It should have been done then (but the longer you go back, the less often it was) and it should be done now, though with brown sleeving instead of red.
Looking at the switch end for one-way switching, it doesn't matter (if it's two-way switching you're out of luck as I've never seen any suggestion they make all brown 3&E cable).
If you're looking in the ceiling rose end, it will be obvious the permanent live is the brown that joins with the in/out-going lives, the switched live is the brown that goes out to the lamp flex, but doesn't matter which brown is which, it's automatically obvious that cable is the switch and any others must be in/out-going.
No, because the sleeving is just marking the blue (or black) as a live wire, not marking it as being switched, so with brown/brown it's already known as live.
For brown/blue (or red/black) the convention is that the sleeve is on the switched, but I don't think there's anything banning you from reversing convention ...
I think we need a better way nowadays. Is it really beyond the senses to actual make wire sleeving that has more than the three colour combinations? After all after a number of years it would be awfully nice to know if a live is a switched live or not. Brian
I would use a neon screwdriver for the final check though - moving OT
- my mate who works for a well known electrical utility says they are now disapproved of as a bulb failure could give false reassurance. I now test the neon screwdriver at the start of each job just in case (though I suppose a bulb could fail at any time).
I don't think it was ever a requirement that the black with red sleeve be used for the switched live rather than the incoming always live. Some might choose to do it that way for consistency, but all that is implied by the sleeving is that the wire is live under at least some circumstances, and not a neutral connection.
While your practice of testing on a known live and known dead circuit is to be commended, there is no escaping that neon screwdrivers are evil for number of reasons...
There are circumstance where they will give both false negatives and false positives, let alone the direct risk they pose, by using you as one end of a live circuit!
Logic dictates that the switch drop wiring uses the red/brown for the fixed live and the black/blue wire for the returning switched live. However, if such obvious logic can be routinely defied by electricians, I won't be making any assumptions on lighting wiring jobs completed by others any time soon.
The majority of new installations will use a loop in loop out ceiling rose. It would take a very illogical person to feed the switch drop live from the line buss and use the neutral colour. Same applies to using the junction box method.
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