Shed Electrics

[Rosebery]

I have an old shed in the garden which was there when property purchased and has electrics for 2 double 13A sockets and a strip light - also in place when bought - long time ago now.

The shed is basicaly falling apart and I want to replace it. Thats the easy bit - its the electrics giving me some concern. The 2.5mm TC&E supply cable goes out through the wall in the kitchen behind one of the units and is impossible to get at to discover its route without demolishing the drawer pack unit. I cannot trace it back to the Consumer Unit as a result and there is no dedicated MCB on the CU (or marked as such) for it. I cannot therefore tell if it spurred off downstairs/kitchen ring but that is what I suspect. The cable must go under the sidepath and come up into the shed through the concrete base. Its impossible to know whether the cable is in conduit (or whatever) without digging up the path although that might come perhaps clearer when the shed is demolished.

The distance from kitchen wall to shed is approx 4 feet.

Inside the shed is a small fuseboard but it has no RCD.

So my question is this. As I have no intention of providing either aditional sockets or lighting will it be OK to remove the shed around the electrics (ensuring its dead first of course) and erect a new shed around the electrics. I would want to put a small modern CU with RCD in place of the fuseboard.

I know that external electrics are Part P but as I'm not actually changing anything (yes I know the present cable isn't armoured) would this count under the like for like replacement category or do you think I need a PArt P Sparks? I'm doing this on rather a small budget and am worried that I might have to shell out a small fortune if its necessary to bring the whole lot up to Edn 17 spec by a Part P sparks.

Yes I know full you don't compromise safety for the purpose of saving a few bob but I'd be grateful for a steer or two from you learned guys.

TIA

 

[Rosebery]

Anyone?

 

[flameport]

If the supply cable to the shed is only 2.5mm, there is no point in putting a CU in there.
Installing a CU will make this notifiable.

Does the consumer unit in the house have one or more RCDs?
If the supply to the shed is already covered by the RCD in the house, an easy solution would be to put a socket outlet on the end of the 2.5mm cable and add a 3A fused spur for a light.

Of course, if the cable is already a spur, you can't do this, so you really do need to establish where the other end of the cable is connected.

 

[conny]

Switch an appliance on in your shed. Then at the house CU switch each circuit off one at a time, when the appliance in the shed goes off you will know what circuit controls it. You can then progress further from there to determine if it is on its own circuit or one of the other circuits.

 

[Rosebery]

If the supply cable to the shed is only 2.5mm, there is no point in putting a CU in there.
Installing a CU will make this notifiable.

Does the consumer unit in the house have one or more RCDs?
If the supply to the shed is already covered by the RCD in the house, an easy solution would be to put a socket outlet on the end of the 2.5mm cable and add a 3A fused spur for a light.

Of course, if the cable is already a spur, you can't do this, so you really do need to establish where the other end of the cable is connected.

Thanks. The "CU" in the house is a 6 way brown fusebox with single circuits for upstairs and downstairs power. It goes Up Lights, Down Lights, Emersion Heater, Up Power, Down Power, Cooker.

There is not a single RCD in the place! Sorry I lie - use a plug in type for lawnmower etc. Apart from the cooker circuit all other downstairs power is on this single Down Power circuit. I had a ferret about in the kitchen and found (eventually at the back of one of the base units) a Fuse Connection Unit which isolates the power out to the shed when switched off. Does this make the shed part of the downstairs circuit or would you call this a spur?

Sorry I wasn't clearer the current arrangement in the shed is that the 2.5mm directly feeds a surface mounted double 13A socket off which the lighting is also taken.

 

[ban-all-sheds]

It's part of the downstairs circuit - the fact that it's a fused spur doesn't change that.

But the fact that it is a fused spur means that you can have as many sockets as you like in the new shed, and a 3A FCU to supply the lighting. I would advise replacing the FCU you found in the cupboard with an RCD one.

The sockets and lighting in the shed do not count as outdoors, not unless your shed building skills are unbelievably execrable

 

[Rosebery]

It's part of the downstairs circuit - the fact that it's a fused spur doesn't change that.

But the fact that it is a fused spur means that you can have as many sockets as you like in the new shed, and a 3A FCU to supply the lighting. I would advise replacing the FCU you found in the cupboard with an RCD one.

Thanks the issue there is that the cupboard is actually a drawer pack and I had to remove the back panel to find the FCU which I had no idea was there previously. Its really rather inaccessible which I guess is a bit naughty. At least it didn't turn out to be a Junction Box!! Would it have the same result as you suggest to put an RCD FCU the other end of the cable - ie at the shed end?

The sockets and lighting in the shed do not count as outdoors, not unless your shed building skills are unbelievably execrable

Ahh Heres one I did for the MIL last year:

 

[ban-all-sheds]

Its really rather inaccessible which I guess is a bit naughty.

Very - contravenes the regulations. If you had a freezer out there, defrosting because you couldn't find the FCU you'd be p****d off.

Try to find a more sensible place for it.

At least it didn't turn out to be a Junction Box!!

It still has screwed connections.

Would it have the same result as you suggest to put an RCD FCU the other end of the cable - ie at the shed end?

You should still have an FCU at the house end.

Find a way to move it.

Ahh Heres one I did for the MIL last year: