Wiring freestanding lamps into lighting circuit

[Tom W]

Hi,

I'm in the process of updating and rewiring the dining room in our house - I want to add a couple of 5A round pin socket outlets on the lighting circuit to accomodate either freestanding floor lamps or perhaps shelf lighting in the alcoves - decorating decision pending. I'm going to be replacing the existing single switch at the room entrance to a double dimmer (with LV compatible dimmers), one of which will control the main ceiling pendant, and the other of which will control both 5a sockets.

My question - which I suppose is not related only to what I'm doing - is what's the best way to connect the cable to the two 5a sockets. As I see it there are two options: a) serial or b) parallel. Which is the correct one?

Many thanks in advance,

Tom

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[Christian McArdle]

I think with a question as basic as this, I would perhaps consider using the services of a qualified electrician. At least you should consider one to check your circuits afterwards, do the required insulation resistance checks, write the installation certificate etc.

Christian.

[Tom W]

Thanks for your reply. I do intend to get a qualified electrician to provide a thorough check after I have finished the work, but in the meantime I just wanted to check this (simple) question, as it's the only part of the work that I'm doing that isn't clearly documented in any of the books that I have that cover the subject.

Cheers

Tom

[Tom W]

I've just re-read my question, and thing that the confusion may have arisen from my misuse of the terms 'serial' and 'parallel' - what I meant to ask was:

a) connect both fittings to the light switch via a junction box, or b) loop in to one socket then on to the other.

Cheers

Tom

[Christian McArdle]

OK, they are wired in parallel. Almost nothing that consumes power is wired in series, except in electronic circuit design and some dangerous designs of Christmas tree lights. Switches are often wired in series, though.

Other things you should know:

1. You should use 1.0mm or 1.5mm twin and earth cable. DO NOT USE FLEX.

1. Earth conductors should be present. The earth connection should be sheathed in yellow/green striped sheathing intended for the purpose.

2. If neither the switch nor backing box have an earth terminal, do not cut off the earth, as they may be replaced in the future with fittings that require an earth. Fold the earth back on itself and sheath the whole lot, so no metal protrudes.

1. When burying cable in walls, you may only bury them in a line vertically from the fitting/switch upwards. You may not bury them in the wall behind the skirting. You may run them horizontally adjacent to the ceiling, or right up inside an internal corner. You may, but only if absolutely necessary, run them horizontally from a fitting/switch, but try not to. This is most likely to be acceptable for sockets above a kitchen worktop, or where fittings are close together.

Christian.

[Christian McArdle]

That would certainly explain it!

You may use method, depending on what is more convenient.

Firstly, remember that any screw terminals must remain accessible for maintenance. This may affect the method chosen.

Your real choices are:

1. Junction box, switch cable, light output cable socket. 2nd socket either daisy chained off first, or with separate cable from junction box.
2. Use switch as junction box. Requires chocolate block to connect up neutrals. Sockets either daisy chained, or run from separate cables from switch.
3. Use one socket as junction box. Requires chocolate block to connect up permanent live.

If using (2) or (3), use a nice deep backing box to allow space for the connections.

Christian.

[Tom W]

Thanks again - it was the daisy chain vs. separate cables (from switch or junction box) option which I was unsure about. It sounds like it's just a matter of convenience, so daisy chain it is for me.

This is part of a major rewiring project which I've been working on for a while, and for some reason the (presumably pretty common) task of running more than one light, or light outlet, from a single switch is the first thing that I've not found covered in any of the books I have on the subject.

Thanks for the help

Tom

[Richard Porter]

Unless you're wiring two 110v lamps to 220v mains you have to wire them in parallel, but that may not be what you mean. You probably need to bring the lighting supply to one socket, run a cable to the switch and then link the second socket to the first.

[Christian McArdle]

Don't dismiss the non-junction box options as possibilities, though. It can be quite difficult finding an accessible, yet hidden, location for a junction box.

Christian.

[Dave Plowman (News)]

And given that connections are the most likely source of trouble in any installation, the less the better.

[The Natural Philosopher]

Unless you ae running massively powerful lamps, it makes bugger all difference.

you meant 'star wired' versus 'daisy chained'

[Tom W]

[Martin Pentreath]

Now *I'm* worried. Is this right? Am I misunderstanding your meaning?? How else do you get cable from beneath the floorboards to a location just above the skirting?

[Andy Hall]

You're allowed to run a cable vertically or horizontally directly to a wiring accesory (i.e. wall socket, switch etc).

So running the cable vertically up from the floor to a socket is allowed

You can run cable in a 150mm wide band adjacent to a corner or top of a wall.

You may not run the cable in a horizontal band 150mm up from the floor. Basically this is because skirting boards are typically nailed.

.andy

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[Richard Porter]

I assume he means horizontally, behind the skirting board. My question would be how are you going to fix the skirting board? Nails?

On the other hand if I was specifying a new house I would want to have trunking instead of the skirting board so that all wiring (mains, phone, ethernet, etc.) is fully accessible and adaptable.