Driveway Lighting

[p33kev]

Hello peeps, need some help with my driveway lighting. Got the boys in now to build up my walls and soon they will be laying the type 1. So need a quick answer regarding external lighting please.

I am looking to put around 7 walkover lights around the perimeter (area where car will not traverse) and maybe 2 wall lights. The intension is to run a radial type circuit straight to the consumer unit via a switch mounted outside of the understair cupboard.

Questions
1. What size cabling will i need? i am thinking 1.5mm2 as it is only lighting with relatively small load.
2. Will the cable be 3 or 4 core?
3. Is radial the best circuit?

thanks,

kev

 

[rjm2k]

Can the boys not provide a qualified electrician?

I'm not qualified and I'm sure someone who is will be along soon, however:-

1. What size cabling will i need? i am thinking 1.5mm2 as it is only lighting

I believe that you will need to use SWA cable, with RCD protection etc

How long will the run be? You may need to take account of Voltage Drop, but then again maybe not. However, think about future proofing, is there a chance that in the future you may want to run a socket off this circuit say for cutting the grass etc, if so I would save myself a job in the future and use cable suitable for that too.

2. Will the cable be 3 or 4 core?

Will you want all lights operated off a single switch or separate switches? You will need a single neutral plus a live core per switch, so if only one switch then it's 2 cores plus earth. If you want 2 way switching that adds more cores.

3. Is radial the best circuit?

Probably, but then like I said, I'm not qualified and I'm sure there's a host of issues I've not thought of and someone who knows better will be along shortly.

Oh and since you are adding a new circuit and it's in a special location you need to read up on part p and notification/self certification, even if you choose to ignore both.

 

[PrenticeBoyofDerry]

Questions
1. What size cabling will i need? i am thinking 1.5mm2 as it is only lighting with relatively small load.

Providing the distance is no more than 39 metres then yes if greater than that then 2.5mm should be used.

2. Will the cable be 3 or 4 core?

I assume the cable is being routed under ground, so SWA preferred using three core would allow you to take live, neutral and earth from the cores and also additional earth protection from the armoured braid. I would also run a duct for cable containment.

3. Is radial the best circuit?

yes

 

[PrenticeBoyofDerry]

I believe that you will need to use SWA cable, with RCD protection etc

As this is a lighting circuit, RCD protection would be required if the cable was not mechanically protected at any point or not surface mounted/ less than 50mm within walls. So if cable was buried within wall less than 50mm for say switches in t&e then that part would require RCD protection.
So if the correct provisions are taken RCD protection could be omitted.
Unless of course it is a TT system then it would be required.

 

[p33kev]

wow, thanks for the prompt responces.

The length will be below 39m and the armoured cable will be withing the type 1 make up layer.

1 no. switch will be fine to work for all lights.

i just wasn't sure where you would need the 4 core cable and wanted to ensure it wasn't applicable here.

 

[rjm2k]

Again, not sure but in some buried installations you are supposed to run warning tape above the cable.

 

[p33kev]

ok now I need a further help please...

I have laid the swa and looped all 6 lights back to the consumer unit. I have now also bought the light fittings but not sure about the glands and how to terminate the swa.

The light fittings have built in glands at the base 2 locations for 2no. cable entry, but will only take the 1.5mm/2.5mm cable and not large enough for the swa. There are 2 entry points at the base sides within the outer casing where the cable is supposed to enter horizontally. Given that these horizontal entry points are close to the vertical glands, my guess is that the armour is supposed to terminate outside, as the angle is too sharp to bend the stiff swa cable. The section between the outer casing and gland is not sealed and is open at the base, ie section of unarmoured cable exposed to water in the ground. Is this an problem?

Ok so my question is whether i need a gland for armoured termination at the outer casing as the section between here and the gland is not watertight?

 

[ban-all-sheds]

Sounds as if you have bought lights which are not fit for purpose.

You do not want water getting into them, so not using proper exterior glands (CW) is not on.

If you don't use proper SWA glands you won't terminate the armour properly, this is also not on.

As well as having to have room for the glands, the lights have to have room inside for banjos or earth nuts so that you can run a flylead from one to the other to maintain earth continuity - not doing this is most definitely not on.

You really should have used an electrician.

 

[p33kev]

Lights are not installed yet and just want to understand how it will fit together.

I have attached the instruction sheet as perhaps i did not explain myself property.

Just need to know whether i need additional glands to what is already supplied.

In my view the armoured cable is just there for protection and damage and not for any other reason, therefore does it really need a gland termination?

Untitled

• p33kev
• 31 Jan 2013
• 1

 

[bhm1712]

In my view the armoured cable is just there for protection and damage and not for any other reason, therefore does it really need a gland termination?

Yes it does.

The protection is not just mechanical, but also electrical when using the correct glands. If somebody was to dig and chop through the armour and into a live conductor, the properly terminated SWA glands will provide a continuous earth path through the armour.

 

[p33kev]

Great thanks, i will then install glands to the outer casing and use the existing supplied gland for the unarmoured entry into the IP protected area.

 

[ban-all-sheds]

So you are going to have SWA glands on a curved surface below ground?

Good luck with that.

Shall we organise a sweepstake for how long before the first one stops working?

How do you plan to measure the armour continuity once the lights are in situ, BTW?

 

[RF Lighting]

I'm yet to see a successful pavement / driveway uplighter installation.

All I can advise is that the lights are fed from a double pole isolator so that you can completely isolate them when they fill up with water and put a fault on your installation.

 

[SimonH2]

This work is notifiable BTW. Had you not started before April 6th then it wouldn't be.

Apart from the reliability issues, I can't see what the point of these lights is. All they do it shine light up at people and dazzle them - they don't shed any light on where you need it, ie where you are putting your feet.

If the units themselves won't take the cable, then you'd need to terminate the SWA into a separate sealed box and use a short section of different cable to the light fitting. This will be difficult for buried systems.

 

[p33kev]

Putting aside peoples personal view on whether there is any point installing the lights, how do you connect a gland to a 15mm hole in the outer casing. Can you get a 15mm gland? or can i terminate the swa before the outer casing therefore have the inner cable go through the hole.

BTW this will be on a separate isolated circuit with its own breaker.