Garden electrics and Part P compliance

[jamespascoe]

Hi all,

Firstly, thanks to those who responded to my previous post - your advice was very much appreciated.

Ok, my project is progressing well, but I would like to ask some further questions:

I need to bury about 3m of SWA which feeds a CU in my shed. In order to comply with Part P, do I need to bury the cable in conduit ? Also, to what depth should I bury the cable to be compliant ?

Also is it ok to clip my SWA feed to a fence ? I have a section that is 2m long which I would like to conceal behind a fence.

When connecting up to my main CU, which breaker should I use ? My shed CU consists of a 63 amp RCD plus a 16 amp MCB (sockets) and a 6 amp MCB (lighting). My main CU does not have RCD protection. Would I be right in thinking that I need a 16 amp RCD ?

Thanks for your help,

James

 

[securespark]

No.

450mm min.

No.

Depends on cable size, amongst other factors.

You should not have two standard RCDs protecting the same circuit.



What supply type have you got?

 

[jamespascoe]

Hi,

Thanks for the reply - much appreciated.

Off the top of my head, I do not know what the supply type is. If it helps, the house is 20 years old and in Bristol. I'll check and let you know.

The cable is 23 amp 3 core SWA. The only RCD I have is in the shed CU. From memory, I think my main CU is populated entirely with MCBs. So, if something goes through my SWA feed, it will not be RCD protected. That is why I was going to run my SWA feed from a 16 amp RCD in my main CU. Is that not correct ?

Also, is it a good idea to run SWA into my main CU or should I use twin and earth in the CU and bring it out to a junction box ?

What are the compliant alternatives to running the feed along a fence ? Can I run it along the gound instead ?

Thanks very much for your help,

James

 

[comms]

So, if something goes through my SWA feed, it will not be RCD protected

Submain doesnt need to be rcd protected.

Also, is it a good idea to run SWA into my main CU or should I use twin and earth in the CU and bring it out to a junction box ?

I tend to do the latter (adaptable box & t/e into cu), but no reason why you cant terminate the swa gland into the cu housing.

What are the compliant alternatives to running the feed along a fence ? Can I run it along the gound instead

Bury it or if left on the surface the cable will need to be visibly marked/labled along it's length.

I was going to run my SWA feed from a 16 amp RCD in my main CU. Is that not correct ?

If you do this you will have two rcd's in series not a good practise, either use one at the house or one at the shed.
If you use one at the house & it trips it's a walk from the shed to the house to reset the rcd.

 

[jamespascoe]

Hi there,

Thanks very much for the reply.

Ok, so to sum up, I will have a 16 amp MCB in my main CU, run t/e out to an adaptable box and connect up to my SWA externally.

I'll run the SWA along the ground behind the fence and mark it with tape. unfortunately, I cant bury it here because the ground is solid concrete.

Is it compliant to clip the SWA to the house ?

Also, who do I contact to arrange certification ? The local building authority ?

Is this all ok ?

Thanks guys,

James

 

[Taylortwocities]

Ok, so to sum up, I will have a 16 amp MCB in my main CU, run t/e out to an adaptable box and connect up to my SWA externally.

OK re adaptable box.
What is the size of your SWA cable in mm. You said 23amps and cable isnt rated like that. It might be able to carry 23amps but we need to know the cross sectional area.
The fuse/cb in the house needs to be larger than the 16 amp in the outbuilding or you wont get discrimination

I'll run the SWA along the ground behind the fence and mark it with tape. unfortunately, I cant bury it here because the ground is solid concrete.

OK as a last resort

Is it compliant to clip the SWA to the house ?

Yes

Also, who do I contact to arrange certification ? The local building authority ?

Yes. Call them and pay their fee before u start work