Sorry, another shed question I'm afraid !

[andy142]

Sorry if this has been covered before (I did search but couldn't find a clear answer).

I need to run electrics to my shed which is 40m from my house, my neighbour is a retired electrician and he has done me a diagram of what he suggests I get installed. (Before anyone jumps on me about this - I will be getting a qualified electrician to do the work, not my neighbour - and certainly not me !).

The thing is that I have already run the SWA from the shed to the house (we had a new fence installed so used the opportunity) but unfortunately the SWA is not long enough to reach the CU so need to "bridge the gap". (It is inside the house, but not near the CU)

The suggestion is that I run 2.5mm T+E from a spare 32A MCB on the RCD side of my CU (Wylex) to a 13A switched fused spur in the house. From this run 4mm SWA to the shed and terminate it in a 13A unswitched Fused Spur. From this, run 2.5mm to a 30A junction box and wire a socket from this.

My question is, does this sound right ? I will get this done properly but I want to get some idea of what I need before I get someone to do the work so I am not paying over the odds.

The only requirement in the shed is to plug in my outside lights and maybe a stereo.

Thanks in advance for any help, please be gentle !

 

[Spark123]

Tbh it sounds awful.
Sub main directly to the shed from the CU would be better to a consumer unit in the shed.
However as you are probably aware the work is notifiable under part p hence why not get your electrician to specify what is required?

 

[andy142]

Thanks for the quick reply. I will be getting the electrician to specify the work required. Well aware of the Part P bit, thanks

Just wanted to put my mind a rest that my neighbours suggestion was a bit, to put it politely, over complicated.

Any Idea what I should be paying ?

 

[Taylortwocities]

The suggestion is that I run 2.5mm T+E from a spare 32A MCB on the RCD side of my CU (Wylex)

If you run 2.5mm from the CU then the maximum CPD is 20amp!

What size is the SWA from the shed to the house? Am I correct in thinking it is 4mm²???

 

[ban-all-sheds]

The thing is that I have already run the SWA from the shed to the house (we had a new fence installed so used the opportunity)

What size?

How deep?

How was the bottom of the trench prepared?

Is there warning tape above the cable?

Did you take lots of photographs showing all the stages of installation, complete with something showing the depth?

Do you have a good expectation that an electrician will now come along and agree to certify the cable you installed?

And why oh why oh why did you install one that wasn't long enough?

 

[sparkwright]

you should extend your 4 mm swa in the house side with 4 mm t+e. this will allow you to use a 32 a mcb at the consumer unit, which will allow for future additions in the shed.

 

[flameport]

Voltage drop over 40m of 4mm cable will be far too large to have a 32A MCB.

 

[Taylortwocities]

Voltage drop over 40m of 4mm cable will be far too large to have a 32A MCB.

Voltage Drop depends on the current drawn. It seems the OP will only have a socket on the end of it with a light and not much else. I wouldn't think that VD is going to be his biggest problem..