Question about cable and security light

[Daz134]

Hello

We have purchased a security light LINK TO LIGHT

Im looking at adding this light with Flex cable of a run no more than 10 meters on a 3 AMP 3 pin plug.

I would have thought that 1.5mm flex cable will be over kill for this light due to the 1.5mm flex being up to 15 amps in current.

Would I be ok using a smaller cable of 1mm or even 0.75mm flex with a 3amp 3 pin plug?

I would appreciate your thoughts

Thanks

 

[Pete999]

Hello

We have purchased a security light LINK TO LIGHT

Im looking at adding this light with Flex cable of a run no more than 10 meters on a 3 AMP 3 pin plug.

I would have thought that 1.5mm flex cable will be over kill for this light due to the 1.5mm flex being up to 15 amps in current.

Would I be ok using a smaller cable of 1mm or even 0.75mm flex with a 3amp 3 pin plug?

I would appreciate your thoughts

Thanks

Beware of the effects of U/V when running the cable/flex outside.

 

[Daz134]

Hi the cable will be protected from the UV light.

Do you have any advice with regards to the cable size etc

Thanks

 

[MFS Electrical]

Hi the cable will be protected from the UV light.

Do you have any advice with regards to the cable size etc

Thanks

What are you planning on supplying the light from? A fused connection unit from a socket circuit or direct from a lighting circuit. And how so you plan to protect the cable from UV?
There are many considerations and where the cable will actually be run and what it passes through and under can affect the final choice of cable used.
Volt-Drop is also an important consideration which will have to take into account the volt drop of the circuit which the light will be connected to as well as the volt drop imposed by the proposed addition.

Edit; I see that I have missed that section and you plan to supply it from a plug. It would be a much better solution to have a Fused connection unit installed by a professional fed from the socket circuit, who should issue a Minor Electrical Installation Works Certificate for the works completed ensuring that the circuit is adequate and safe for alteration. Also since this would be classed as an addition or alteration it would also be required to be protected by an RCD under the 18th Edition Wiring regs (circuits supplying luminaires in domestic premises). Another reason for employing a professional is many manufacturers require proof that an installation was carried out properly, in line with current regs by a suitably qualified and competent person before they will honour warranty claims. It would be a shame if you were to come unstuck with this, particularly as the floodlight isn't particularly cheap to begin with.

One other important point to consider would be, and I may be wrong on this but others will come by and correct me if so, but I believe in England you have to notify Building control of external installations, which would include exterior lighting. (we are based in Scotland hence why we don't know for certain.)

For external lights and the like I'd recommend HO7RN-F flex as it is resistant to weather and UV.

 

[Daz134]

Hi

Thanks for the reply

I'm just going to connect it as mentioned above to a 3amp 3 pin plug.

So I'm going to wire the light using the 1.5mm flex into a 3amp plug.

I was thinking as long as the fues is lower than the rating of the cable there is no chance of fire due to the low fuse rating.

Thanks for any advice

 

[Pete999]

Hi the cable will be protected from the UV light.

Do you have any advice with regards to the cable size etc

Thanks

 

[Daz134]

Hi

Thanks for the reply

But seems a bit much just to put an led security light up in the back year.

The cable is going up the wall through a hole in the wall into a plug which will be 3amp. The cable run is about 3 metres if that.

It's an led light so very little power.

Seems a bit much to get building regs involved to install a small security light with a cable run less than a hair dryer.

I do appreciate your advice though. I was just hoping to put up using a 3 amp fues in a plug with 1.5mm flex.

With a 1.5mm fles less than 3 meters and a 3amp fuse powering a small led lamp surly this is going to be OK isn't it

Thanks again for your advice

 

[Pete999]

How is the cable protected from U/V?

 

[Daz134]

The cable will be going down the back of the drain pipe and held with cable ties and straight into the wall

 

[pc1966]

As already said, you should be using UV resistant cable, or run it in conduit/trunking to keep the sun off. For a few months it may not matter, but a few years can seriously degrade some types of rubber/plastic materials.

While it seems overkill from a current carrying point of view, the simplest choice is 1.5mm H07RN-F cable as that is fairly tough and UV resistant. Unfortunately I don't think they make UV tolerant mains cable smaller than that.

 

[Daz134]

I will get the cable you have recommended with regards to the UV.

Is it OK to run in a 3amp fuse on a 3 ping plug

Thanks

 

[MFS Electrical]

Hi

Thanks for the reply

But seems a bit much just to put an led security light up in the back year.

The cable is going up the wall through a hole in the wall into a plug which will be 3amp. The cable run is about 3 metres if that.

It's an led light so very little power.

Seems a bit much to get building regs involved to install a small security light with a cable run less than a hair dryer.

I do appreciate your advice though. I was just hoping to put up using a 3 amp fues in a plug with 1.5mm flex.

With a 1.5mm fles less than 3 meters and a 3amp fuse powering a small led lamp surly this is going to be OK isn't it

Thanks again for your advice

No problem, if I'm right in what I'm saying regarding the building regs and notification being required. it is a fairly simple process which the Electrician can complete along with certification at no extra cost or hassle to you as long as they are registered with the likes of NICEIC or NAPIT. Thing is if anything ever went wrong the blame would fall on your shoulders for not following procedure as its the homeowner who has the duty to comply with the regulations.

I do appreciate that it may seem overkill to apply all of the factors mentioned above but they are requirements of the IET wiring regs and are designed to ensure that the equipment is installed in a safe manner and will not cause fires etc.

You are correct to a point regarding the fuse rating vs the cable rating but other factors applied from the wiring regs can effectively de-rate the cable which is where the danger of a fire may come in albeit a remote one in the particular circumstance mentioned.
Volt drop as mentioned previously is likely to be the highest concern as the Volt drop from origin allowed for lighting is lower than that of power circuits. If the installation is carried out as planned and the volt drop is an issue it may be that the electronics inside the fitting will not last as long as intended and the manufacturer without proof of correct installation may veto your warranty claim.
One final point to consider is that should the worst happen and god-forbid there was a fire the insurance companies have been known to veto insurance claims if it is found that the electrical installation has been altered or added to by anyone other than a qualified electrician. Thankfully this is rare but it can and does happen.

Anyway I'm not trying to preach to you, it is, after all your house and you will do as you like, as you are entitled to, Please just be mindful of the risks associated with electrical work and ensure you follow safe isolation procedures before carrying out any works.
If in any doubt at all I urge you to contact a fully qualified electrician to help.


N.B H07RN-F is available in sizes from 0.75 - 6.0mm for future reference ?

 

[loz2754]

This work is not notifiable in England.

 

[pc1966]

I will get the cable you have recommended with regards to the UV.

Some places sell it by the meter, whiche helps, but measure twice and add a bit:

Superlec 3CORE 1.5MM 3183P H07RN-F EPR / PCP FLEXIBLE MAINS CABLE - EN60332-1-2

H07RN-F Cable is a non armoured flexible mains and control cable designed primarily as a trailing cable for use in the supply of energy for portable or mobile equipment.The cable is Ideal for use with transformer pumps, welders grinders, temporary lighting cable and feed cables to heavy mobile...

www.superlecdirect.com

Is it OK to run in a 3amp fuse on a 3 ping plug

Yes, it should be fine for a 13A plug and 3A fuse.

Just check the socket feeding the outside stuff is RCD protected. Most installations where the CU (consumer unit = fuse box) was installed/updated in the last decade or so will do, but if not you really need to get RCD protection, either for the whole house (preferred) or for that socket alone.

 

[Daz134]

Thanks for the advice

When buying that cable should I go with 0.75mm, 1mm or 1.5mm

Thanks