To use 1.0mm or 1.5mm wire? (lighting)

[htmark98]

I want to install a light in the shed aswell as deck lights and a garage light, these wont be on the same load. I'm putting a 5 way CU in the shed. But i was going to use 1.0mm for the shed light and can i use the same as that for the garage (2 lights) and decking/outside apprix 5 light. I'd rather use 1.5mm but will this be ok just for one light on it's own?

[Harry Bloomfield]

htmark98 expressed precisely :

Assuming they are all normal lights 1mm would be adequete, but it is more common to use 1.5mm for all lighting circuits. The cost difference is tiny and 1.5mm is more robust.

[Alistair Riddell]

Assuming a normal lighting circuit with 6 A protection, you can use 1 mm2 except in the most improbable of installations. However it will do no harm to use 1.5 mm2 and it does have the advantage of being a bit more mechanically robust.

[Set Square]

Doesn't it depend on what the lights are? There's a bit of difference between a 40 watt glow-worm and a 1000 watt searchlight. Tell us what electrical loads you wish to carry - in terms of watts (and thus amps) and you may get a sensible answer.

[David Hansen]

On 18 Jan 2006 10:38:19 -0800 someone who may be "htmark98" wrote this:-

So far so good.

The same circuit?

Seems a trifle excessive. What is wrong with one way for lighting and one way for power?

Sounds fine, unless it is a very large shed with a very large light.

Do help us. What power are these lights, what sort of light?

Ditto.

I suspect that this question indicates that you don't know enough to do the work yourself.

How will electricity get to the shed? How will it be earthed?

[htmark98]

Hi sorry for not answering all facts

I havent got the lights yet, but the lights will be approx 100w (maybe less) strip lights. So 3 of those, the outside decks lights are 40w each (3 again) and outside lights are 60w max (2 of these).

I was advised to get a 5 way as it'll be set up like this

6.0mm from consumer unit with 40a MCB

Then into the shed with a 5 way RCD

1) 3 Double Sockets on redial (30A MCB 2.5mm) 2) Freezer on it's own circuit FCU (16A MCB 2.5mm) 3) Shed Lights 1 inside, 1 outside(6A 1.5mm) 4) Garage Outlet (30A MCB 6mm SWA) 5) Will be Spare

Then Garage will have 6mm SWA going to it and then inside

A Garage will have a RCD small enclosure with the 1 Double socket, and

1 outside double and lights and decks lights will be from fcu spurs.

[David Hansen]

On 19 Jan 2006 03:00:31 -0800 someone who may be "htmark98" wrote this:-

Without commenting on any other part of your posting, one think leaps out immediately. Unless you intend to use MI cable, 2.5 is too small for a 30A radial circuit.

You still haven't told us how you intend to earth the system.

[Christian McArdle]

A genuine radial, with an individual run of 2.5mm back to the MCB, with no section of cable supplying more than one double socket would normally be OK on a 32A MCB, at least for moderate lengths.

Christian.

[Andy Wade]

Yes, but a 20 A radial circuit would (almost certainly) be entirely adequate for the intended use, and would avoid the need for design calculations. Does the floor area of the shed exceed 50 m^2?!

[Christian McArdle]

Indeed. A 20A MCB would be more appropriate in this case, but I just wanted to make the point that a 32A radial can sometimes be implemented in 2.5mm cable.

Christian.