cable to outside shed

[Desie]

Hi guys

I have planned a power system to the brick shed about 4 metres from a house. Can you tell me if it's right?

2.5mm SWA from the house to the shed terminating in the shed in the form of a metalised 13A fused switch. The fused switch then feeds 2 sockets in a radial circuit. In addition it also feeds a light via another 3A fused switch.

The supply will have it's own breaker in the CU. I have a spare 32A MCB at the moment on the RCD side of the CU. Can I use this?

In the house I was planning to terminate the SWA below some kitchen units into a JB. This will then provide a standard 2.5mm T/E feed to the breaker at the other end of the house.

I am planning to use 3 core SWA to provide me with a sleeved earth connection via the junction box as well as the metal FCU with the armour providing a further earth to the metal back box.

Is there anything I haven't thought about?

 

[Adam_151]

You're going about things in a rather strange way, why not just loose the first FCU and use a 20A breaker?

What type of junction box are you planning on using for the SWA?

Is this a wooden shed? What are the earthing arrangements at the main board? TT? TNS? TNCS?

EDIT: btw, this work is notifiable to your local building control office, whether or not you honour your legal obligation to do so is entirely upto you, however failure to notify at this time may hold up a future sale and/or other financal or legal arrangements.

 

[Desie]

Thanks Adam

I wanted to ensure that there was an isolation point in the shed as well as at source. It also gives a convenient point for branching off to the two points for sockets and light.

The shed is actually a brick outhouse.

Inside the house the SWA terminates through a metal gland but with no earth for the shield. Hence the reason I have used the 3rd of the 3 core strands to earth both ends through to the CU via a standard 30A JB. The earth then connects to the metal back box and FCU in the shed earthing the back box, sockets and light system and SWA shield at the same time.

Earthing arragments for the system is PME/TNC-S

Regarding notifying, I am actually PartP'd but tend to do work in domestic internal rather external. I don't do too much using SWA.

 

[Adam_151]

Thanks Adam
Inside the house the SWA terminates through a metal gland but with no earth for the shield.

You should earth the armour at the supply end of the cable, use the banjo for the SWA gland, a brass bolt, and a 'hoop' crimp, of course if the gland is into a metal enclosure if you make sure the metal is bare, etc, its probably not strictly neccessary, but using the banjo gives an added reassurance, if you are using a separate core as the CPC, its unneccessary to connect the far end of the armour to the earth (as the armour is already earthed at the other end), however doing so will reduce your Z's slightly so you may as well do it

Hence the reason I have used the 3rd of the 3 core strands to earth both ends through to the CU via a standard 30A JB. The earth then connects to the metal back box and FCU in the shed earthing the back box, sockets and light system and SWA shield at the same time.

I'm not quite sure I follow, any chance of a pic?

Earthing arragments for the system is PME/TNC-S

Does the shed have other services such as water or gas, or any structeral metalwork?

Regarding notifying, I am actually PartP'd but tend to do work in domestic internal rather external. I don't do too much using SWA.

*grabs some popcorn and sits back* ...

 

[Desie]

Adam

Using the separate core was a way to avoid having to tale the SWA all the way to the supply as it was impractical. I wanted to make sure all of my options were covered for earthing to be safe.

I'm not quite sure I follow, any chance of a pic?

Sorry can't at the moment but needless to say there are lots of earthing options and they are all green/yellow sheathed.

Does the shed have other services such as water or gas, or any structeral metalwork?

No so no need for supp bonding.

*grabs some popcorn and sits back*

Enjoy but no fireworks to watch.

Does anyone have a picci of the correct way to connect SWA at supply and load ends?

Thanks Adam