Outdoor wiring question

[Bluenose1940]

Hello folks,
I currently have a waterproof box out in the garden which is fed by an armoured cable from the house. This currently provides power via switches and sockets for a small pump in a water feature and a few lights around the garden, both of these items run off transformers within the box.

I have now installed a small summerhouse some 20 metres from this box and, it is my intention to run a length of armoured cable from the existing box to the summerhouse where I want to install a junction box up under the eaves, to connect to the 2.5mm twin and earth cable in the summerhouse. What IP rating box will I need and what sort of connector will be needed within the box to connect the two cables please.
The power in the summerhouse is needed purely for music (CD player or suchlike) and some fancy fairy lights (my wife's description!)
Once it's all in place I will get it signed off by an authorised person.
Many thanks.

 

[telectrix]

you'll need an IP55 (or better) adaptable box, push fit wagos, SWA glands with banjos or earthing nuts, fly lead for the earth, i assume that you are competent to do this, otherwise get a local spark to do it. most sparks will only "sign off" work that they have done or supervised throughout.

 

[Spoon]

What size is the current armoured cable?
What does this armoured cable wire back to in your house?
What size fuse/breaker is protecting this armoured cable?
What will be the overall length of the armoured cable be, once you have extended it? You only mention that you are extending the current cable by 20 meters.

 

[Bluenose1940]

Thanks for coming in on this Spoon. All I can see of the current cable is that it is twin and earth 2.5mm (15mm O/S dia,) it goes back to a fused spur in the house which in turn goes to a new consumer unit in the garage. The overall length of armoured cable will be approx. 25 metres ( existing 10mtrs + 15 mtrs extension)
Edit: the new extension cable is twin and earth with an O/D of 20mm. It came as a freebie as it was excess to a friends job.

 

[Spoon]

All I can see of the current cable is that it is twin and earth 2.5mm (15mm O/S dia,) it goes back to a fused spur in the house which in turn goes to a new consumer unit in the garage.

Hi mate. Confused now. (doesn't take much)
Is the cable going from your house fused spare to the junction box for the pump an armoured cable or twin and earth?

 

[Pete999]

Thanks for coming in on this Spoon. All I can see of the current cable is that it is twin and earth 2.5mm (15mm O/S dia,) it goes back to a fused spur in the house which in turn goes to a new consumer unit in the garage. The overall length of armoured cable will be approx. 25 metres ( existing 10mtrs + 15 mtrs extension)
Edit: the new extension cable is twin and earth with an O/D of 20mm. It came as a freebie as it was excess to a friends job.

Your 1st post said the cable was armoured now it's 2.5mm2 twe???

 

[Bluenose1940]

Sorry for the confusion chaps. The cable from the house (fused spur) is armoured cable. I referred to it as twin and earth merely because there are three cables within the armour. I assumed Live, Neutral and earth. Apologies.

 

[Spoon]

Your 1st post said the cable was armoured now it's 2.5mm2 twe???

Yep, that's what I've asked as well. We need the OP to clarify things.

OP: More questions that need answering:

What is the installation method of the armoured cable (or twin & earth) from the fused spare to the pump JB? Is it under ground, clipped to a wall/post?

What is the intended installation method of extension cable?

 

[Bluenose1940]

The existing cable is underground. I have a choice with the extension (I think) I can either bury it alongside the fence or I can clip it to the base of the fence. Neither area is easily accessible once the job is done as the area is thick with shrubs.

 

[Pete999]

Sorry for the confusion chaps. The cable from the house (fused spur) is armoured cable. I referred to it as twin and earth merely because there are three cables within the armour. I assumed Live, Neutral and earth. Apologies.

How big it, 4mm 6mm 10mm???

 

[Bluenose1940]

How big it, 4mm 6mm 10mm???

The O/D of the existing cable is 13mm. I can't actually see the diameter of the individual wires without dismantling things.

 

[Octopus]

You need to find a spark too work with and get them to give you instructions and parts suggestions. Best of luck with that

 

[Pete999]

The O/D of the existing cable is 13mm. I can't actually see the diameter of the individual wires without dismantling things.

Can you not see any writing on the cable sheath?

 

[Bluenose1940]

No sorry. I can't see enough of the cable.

 

[Pete999]

You will be restricted to 13Amps as is if the Cable is connected to a Fused Spur, may be best to get an Electrician in to do the job properly Rather than leave it as a DIY bodge.

 

[Bluenose1940]

You will be restricted to 13Amps as is if the Cable is connected to a Fused Spur, may be best to get an Electrician in to do the job properly Rather than leave it as a DIY bodge.

The original armoured cable was put in by the electrician when we had the extension built. On the basis that the water feature pump and the lights are all powered by transformers, down to 12v I think, surely an extension to the armoured cable to provide power for a CD player and some fairy lights isn't going to cause an overload.

 

[Pete999]

The original armoured cable was put in by the electrician when we had the extension built. On the basis that the water feature pump and the lights are all powered by transformers, down to 12v I think, surely an extension to the armoured cable to provide power for a CD player and some fairy lights isn't going to cause an overload.

It's not just a case of overloads, long runs will be subject to voltage drop, earthing will need to be thought about, are you going to have any other services in your Summer House, to top it off I very much doubt if you will fins an Electrician to sign off this installation.

 

[Spoon]

If the existing cable is 2.5mm then a 25 meter lengths should be ok for voltage drop.
You can guarantee the missus will try and stick more stuff onto the circuit once its in. After all, for the general public, if they see a socket then anything can be plugged into it... 2kw heater for winter... dryer...

 

[Spoon]

Once it's all in place I will get it signed off by an authorised person.

If you are going to do this then get the person round before hand. They can check out the existing circuit and let you know if what you want to do is ok.

 

[Bluenose1940]

OK. Many thanks to all for the advice and guidance. I will 'get a man in' asap.

Thanks again.