Bathroom lighting circuit

[Grumps]

Is it acceptable (to wiring regs) to T-off the loft-based lighting circuit (junction box) with T&E and take this to a pull-cord switch, switch just the L keeping the N&E intact, and then take this to the light fixture?

Or do I HAVE to take the T&E to the light fixture, then run a separate piece of T&E to the pull-cord switch, with the blue sleeved with brown to indicate switched L? The ceiling light in question only has terminals for L,N & E, so a junction box would be necessary for the switched L.

[Tricky Dicky]

The methods of wiring lighting circuits is outlined in the DIY Wiki and are all still valid. What you are proposing can be done either with junction boxes or loop-in rosettes. In my daughters new build all the loop in is done with T&E at the switches the advantage of that system is that it provides a Neutral at the switch which some of these smart switches may require.

In my recent rewire I removed a singles based system where the Line looped in at the switches whilst a single neutral simply connected all the ceiling rosettes. Owing to the the low 22deg pitch of my roof and not being able to even stand up in the loft and the prospect of claustrophobic working between trusses not to mention 270mm of insulation to cope with. I boarded a crawl space through the centre of the loft and ran the mains feed through a series of Wago boxes to which the related switch and light fitting connected so all that appeared at the light fitting was N&E and a switched L.

Richard

[John Rumm]

Yup, that is one way of doing it... sometimes its the obvious solution when the switch position is "on the way" to the lamp.

The (probably slightly more common) way would be with a 4 terminal junction box, with separate cables to the switch and lamp positions.

Vis:

So called "loop in" wiring - also acceptable - but not the only way of doing it.

In many light fittings there is space for an additional terminal (e.g. wago or chock block) if required...