"best" way of wiring lighting circuits? Complete re-wire

Fan feed is a fairly big point imho, I'd look to include unswitched live at the ceiling lighting points whatever scheme is used.

If you did it would suffer one of the 2 downsides of the Carter system, which was outlawed in the 1930s. Ie that a switch failure is liable to short out the supply, its a fire risk.

With a tool they could be, ie by unscrewing the light fitting first. Also one can solder inside the jbox, fit the wires in the screw connectors as normal, but leaving long tails, and solder those. The screw cons then provide mechanical restraint for the solder joints.

you can have it anywhere you want by using an extra cable core.

again you get L, swL and N anywhere you want by fitting the necessary singles to provide it.

well, yes :) ... I doubt its what you'd want though.

NT

When I rewired a house for home automation, I ran all the switch and lighting point wires back to central connection points (actually consumer unit shells, because the DIN rail made it easy to mount X10 dimmers and relays). It's easy to change the way things are switched, rather like a Cat5 wiring closet, and (important point for selling) it's easy to strip out the home automation control and revert to manual operation.

All switch drop cables are triple and earth, which allows either to get a neutral to the switch or to add a second switch in the future. Again, many of the lighting points are triple and earth, for future flexibility.

Agreed - don't like this as it bones you if SWMBO gets one of those Ikea fittings with sod all space for terminals.

Pity they don't do a flush ceiling rose but you could DIY one with a round dry lining box and terminal strip...

No! There's no guarantee that the switch is break-before-make (unless it says so) which would result in a rather noticeable bang followed by no lights.

Hager-Ashley maintenance free JBs with spring terminals. The jury is still out on their longevity but the regs allow these, because the manufacturer rates them as fit for purpose. But I personally wouldn't stick then under tiles or laminate just in case! Under floorboards is fine, and under easily liftable floorboards, you could use a screwed JB anyway.

And you'd need either full *continuous*[1] conduit/trunking or double insulated singles. Unenclosed single-insulated singles (wibble) are NOT allowed anywhere.

JBs in a more remote but accessible location? Eg group them in a few locations and have little access panels in the floor. More cable required, but easier to maintain.

As all my lighting is run mostly on one level, with a dormer conversion, I've made up 4 large junction boxes with DIN rain and DIN terminals. One in each quadrant of the house, in the corner voids behind the dormer room walls (where there are large accessible voids).

Not for everyone - costs more (could have used lots of regular JBs for the same effect, but I want somewhere to stick relays for a bit of remote control) and needs more cable. However, not *that* much more in my case due to the layout.

Another option - permanant power to all lights and fit radio controlled units to each one. No cables to the switches. Cool, but costs a fortune. getting more popular though - check out Homebase and B&Q - they seem to be increasing the range of these units.

My lighting is (will be) all wall fittings or lighting outlet sockets. (fortunately my wall fittings are large enough to change the terminal block inside for something with more ways).

I'm doing loop-in to *most* of them, with 3-core droppers to the switches (for the same reasons you suggest).

But I will have to do some loop through connections in back boxes - I'm planning to use single crimps with heatshrink sleeving.

Cool!

How would you handle multiway switching in such a scheme?

Multiple X10 senders (switch) for one address (light)?

Couple more options:

Mains to the light fittings, with the cable to lightswitch being cat5, run on 12v with a relay

- you can then use anything at all for the switches, which much opens up the decorative possibilities

- you can also add no end of extra switch ways later if desired

A ring circuit for lighting gives increased safety and reliability.

Its sometimes worth adding extra cable cores, so that later there is the option to add a greater number of switch ways, enabling easy switching between differing lighting levels.

NT

With home automation, all the switches are momentary action anyway, so I simply wire multiple switches to one of the computer inputs.

If I strip out the home automation, I can fit impulse relays in the consumer unit shell and continue to drive with the existing momentary action switches.

Special thanks to you Tim and also to NT for pointing out problems with this!

Fine upstairs (JBs grouped in loft) but _really_ painful for downstairs lights.

Downstairs I think I'll just loop into switches, join neutrals using a chocolate block (one bit of!), and go from switch to fitting with 3- core + earth to allow me to send unswitched live to fitting later if I need to.

Shall I leave the initially unused strand of 3-core "floating" (I'm worried about it touching something live and causing problems), or parallel it to the switched live both ends, or wire it into the earth both ends to keep it out of harm's way?

Cheers, David.

I usually earth spare cores.

Adam

Yup. Very useful if you decide to add table lights etc switched from the same place at a later date.

I usually leave spare cores unstripped and put tape over each end, so it looks spare, and not a possible replacement to a broken earth.

Toby...

Hang on a second - with standard 3-core + earth (brown, black, grey), I don't have a blue for neutral.

I'm sure I've used 3-core before with one of those colours carrying neutral (interlinked smoke alarms being the most obvious; brown = live, black = neutral, grey - interlink I think) - but where in the regs does it say that this is allowed?

Specifically, the on-site guide says neutral = blue, and that's it.

Brown obviously works for live, and black and grey obviously work for switched live - but black or grey for neutral - where does it say I can do that?!

Cheers, David.

You need some blue sleeving.

Good practice is to sleeve the grey not the black with blue sleeving and use that as the neutral connection where needed.

Adam

You sleeve it blue. All the regs are concerned with is that "live" (meaning live and neutral) conductors are suitably insulated and protected and that the are identifiable at the ends. The only conductor that must not be abused is the CPC/earth. You cannot use a green/yellow marked conductor, nor the bare conductor in T+E cable for any purpose other than the earth (identification and the fact that the CPC in T+E is only protected by the sheath and is also usually undersized).

You can use an otherwised marked conductor as a CPC though provided it is marked (cf using one of the conductors in SWA as well as the armour to transport the circuit CPC (and possibly bonding or earthing conductor

- the roles are different although a single conductor may combine more than one role).

All lights on a radial with electronic control at the fittings X10 being the most common but not the best. Switches are cordless.

X10 spread this way is common when retrofitting home automation, but if you're rewiring anyway, I would question it.

Although I mentioned X10 before, very little of my home automation is done with X10 - actually for main lighting, only one room, and that's because I wanted a dimmer. Other than that, I use DIN mounted relays - much cheaper (and more reliable than X10).

I do have some other bits of X10 - tends to get used when I put something new onto home automation, before I get around to providing what I regard as the more permanent solution (relay switching).

OK - will just swapping the last 1-2cm of the insulation for blue insulation (stripped from a blue wire elsewhere) do? That's what I've done in the past to mark the blue as brown in a switch feed (but back then, no one was checking!).

Why grey not black? (Just interested).

I was going to use brown for the switched live - but then thought "if/ when I want both switched and unswitched live down this cable, brown will definately be unswitched live, so grey (or following your advice, black) will be switched".

Pity there's no proper guide on the use of 3-core colours in various scenarios, including this one. Am I correct in believing this means it doesn't actually matter?

Cheers, David.