Connecting IP44 Dusk to Dawn switch timer on 32A outdoor socket?

[Samsg30]

Hi Guys,

I just want to double check my understanding before I start this small piece of work.

I have got few spike lights setup in the garden which I want to turn on automatically at dusk and adjust the swtiched on time from few hours to dawn. Toolstation is selling IP44 dusk to dawn switch timer which suits my requirement.

I have an outdoor IP54 socket in the garden which is supplied from the mains with 32Amp RCBO.

10 Spike lights are fitted with 3watt LED GU10 bulbs so only 30watts in total electricty is required. However 3amp fuse is just for little additional safety (or false sense of safety ) as opposed to 13amp fuse or no fuse plug

I am planning to connect spike lights via dusk dawn switch to the socket using simple fused plug and I'll put 3Amp fuse instead of 13Amp and leave it on all the time so lights will come on / off via dusk dawn controller.

Can you think of any risk here?

- I assume if there's a short circuit, or current leak via earthing, RCBO at the end of outdoor wall socket will still trip.

- It present no "deadly" hazard if kids accidently touch the light as maximum shock would be 3Amp and that too RCBO 30mA should trip pretty quickly.

- Also in case spike lights develop a leak, I can simply unplug the wire from socket to avoid tripping RCBO when I need it to run lawn mower etc.

Can I use standard 1.5mm black cable (not armoured cable) outdoors as only small end of it will be buried in the ground rest everything will be above ground. Spike lights are all setup with SWA cable.

Thanks for your advise.

 

[ban-all-sheds]

Can you think of any risk here?

Yes - ones which stem from you not knowing how to do this properly.

I assume if there's a short circuit, or current leak via earthing, RCBO at the end of outdoor wall socket will still trip.

Not necessarily - depends on the magnitude and duration of the currents.

Why are you anticipating a "current leak via earthing"?

It present no "deadly" hazard if kids accidently touch the light as maximum shock would be 3Amp

You must have some pretty robust kids - 3A is about 10x the amount of current which can kill an adult.

And if you think that 3A figure is because of a 3A fuse, did you know that one of those will pass 5-6A pretty much indefinitely?

and that too RCBO 30mA should trip pretty quickly.

For most faults yes.

But your attitude is analogous to driving a car with a policy of "Nah - doesn't matter if I crash 'cos it's got airbags".

Can I use standard 1.5mm black cable (not armoured cable) outdoors as only small end of it will be buried in the ground rest everything will be above ground.

No.

Spike lights are all setup with SWA cable.

Really?

Properly glanded at each light? By an installer, or made like that?

What are you going to do with all the other ends of these cables, one per light, running back to your timer?

 

[endecotp]

Spike lights are fitted with LED GU10 bulbs which will require about 30Amps in total electricty.

That's a lot, are you sure? How many lights are there?

maximum shock would be 3Amp

That's a hell of a big shock.

 

[Samsg30]

Thanks for your quick reply.
All garden lights are setup by certified electricial using swa and glands. Well, spike lights comes with soft black cable (non armoured cable) which are connected to one single SWA cable using IP55 junction box with glands and magic gel inside. Junction box, swa cable and some part of soft black cable is all buried underground.
All lights are connected to one circuit supplying security flood light, Patio light as well as garden light. This circuit is also at 10Amp RCBO.
Problem is, one or two spike lights seems to be faulty where some water seeps in during torrential rains and trips the RCBO.
However issue goes unnoticed until I manually turn on spike lights or go out in the garden to find out tripped RCBO and this is actually making security lights useless.

So idea is to separate out spike light and put them in socket (which is only used during lawn mowing) along with facility of auto turning on/off feature using dusk dawn controller. That way, I will know when fault is developed and will only trip socket RCBO, leaving patio and security lights working fine.

However my question on kids touching light accidently is hypothetical as if there is a short circuit or current leak (live touching light body due to water ingress), RCBO will trip long before you'll see lights working.. well that is what it is designed for (as told by electrician who installed them at first place)

So the only question remains, is there any added risk of attaching garden lights to the socket with lower amp fuse and what is the alternative of SWA which I can use to cover a distance of about 3 feet from SWA cable end and socket (with dusk dawn controller inbetween)?

Reason I am asking for SWA alternative is I don't have this cable anymore and no store is giving me 1-2 meters of this cable. However I have black 1.5mm cable with suitable outer layer which is as robust as the soft black cable supplied with spike lights.

Here are the steps: -

1) 10 SPIKE lights (with soft black cable) ----> already attached to one long SWA cable using glands, junction box and gel and buried underground

2) Attach other end of SWA cable to first end of "recommended alternative of SWA cable" using gland, junction box (all IP55 and above ratings) and bury in the ground

3) Attach second end of soft cable to Dusk dawn control and install it 2 feet above ground

4) Run a small piece of cable from Dusk Dawn (supply connection) to socket using 3Amp plug

5) Job done.


Hope this makes sense?

 

[Samsg30]

That's a lot, are you sure? How many lights are there?

I meant to say 30 watts 3 watt x 10 lights

That's a hell of a big shock.

Yep.. understood that .. hope RCBO will will take care of that before situation of electric shock arises.

 

[endecotp]

I'm sure you can find someone on ebay who will sell you SWA by the metre.

 

[EFLImpudence]

Already answered. I missed it.

 

[Samsg30]

Already answered. I missed it.

I edited the post as I meant to say 30 watts. However fuse size is not of a concern here.. just mentioned that in case if it will provide any safety as opposed to using default 13amp fuse or no fused plug.

 

[FrodoOne]

You must have some pretty robust kids - 3A is about 10x the amount of current which can kill an adult.

With AC, 3 A is about 50x the amount of current which can kill an adult. (http://hypertextbook.com/facts/2000/JackHsu.shtml)

 

[Samsg30]

any suggestions guys or the intended setup I specified looks OK?
Understood all about danger of 3amp and I am proposing mainly in case of short circuit, fuse blows up quickly enough than buring wire etc
Necessary safe guards are provided by RCBO at the end unless you think otherwise and have better suggestion to improve.

Also can't think of a reason for not using black outdoor cable (not swa) for last 3 feet when there is no apparent reason to dig there and all spike lights have similar cable buried underground already to the junction box connected with SWA cable at the other end.

 

[ban-all-sheds]

all spike lights have similar cable buried underground already to the junction box connected with SWA cable at the other end.

That's wrong.

Dig it up and do it again with armoured cable.

 

[ban-all-sheds]

All garden lights are setup by certified electricial using swa and glands. Well, spike lights comes with soft black cable (non armoured cable) which are connected to one single SWA cable using IP55 junction box with glands and magic gel inside. Junction box, swa cable and some part of soft black cable is all buried underground.

Then whoever did that was not much of an "electrician", and the certificate he gave you is false.

Problem is, one or two spike lights seems to be faulty where some water seeps in during torrential rains and trips the RCBO.

Either poorly installed (do it again), or carp lights (replace them).

I have black 1.5mm cable with suitable outer layer which is as robust as the soft black cable supplied with spike lights.

The cable supplied with the lights must not be buried and must not be concealed.

 

[ban-all-sheds]

1) 10 SPIKE lights (with soft black cable) ----> already attached to one long SWA cable using glands, junction box and gel and buried underground

What sort of gland was used for the cable to the lights?

2) Attach other end of SWA cable to first end of "recommended alternative of SWA cable" using gland, junction box (all IP55 and above ratings) and bury in the ground

There is no recommended alternative. And if you bury an IP55 junction box it will leak.

3) Attach second end of soft cable to Dusk dawn control and install it 2 feet above ground

Do you mean the other end of the cable installed at #2? That will be SWA, so it will need glanding into the timer. And this doesn't look like it can accept a gland. (Did you read the review of that timer, BTW?)

4) Run a small piece of cable from Dusk Dawn (supply connection) to socket using 3Amp plug

5) Job done.

No, job not done.

TESTING.