Wiring a shed for electricity.

DogsBody

DogsBody

DogsBody

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Currently in my house is a fused switched spur (fuse removed)
connected to this is an armoured cable which has been ran to the bottom of the garden, in preperation for my shed arriving.

What do I need in order to utilise the cable (ie to go from armoured cable to consumer plug socket)

I think I would need the following
1 - Armoured cable gland
2 - metal junction box
3 - smallish RCD consumer unit (not sure what rating to have on the main breaker or the socket breaker, but i know 6a is the generally accepted standard for lighting)

beyond this point I am fairly happy with what I need to do, ie wiring and sockets/fittings.

I know I can ask the electrician about all this when he comes to wire up but I would rather get prices myself and buy the stuff myself if I can get it cheaper online than direct from the electrician.
 
Few little things to consider here,

What size is the Armoured cable?
What size is the breaker protecting the fused spur?
Is that circuit RCD protected?
What is it you want to run in the Shed?
 
ZG002 said:
Few little things to consider here,

What size is the Armoured cable? don't know how can I check?
What size is the breaker protecting the fused spur? don't know but is this relevant if the breaker is larger than the 13A fuse in the spur?
Is that circuit RCD protected? it is a new build house so the whole house is on a brand new fuse box/RCD box
What is it you want to run in the Shed? tumble dryer/chest freezer/hifi/power tools/outside lighting/lighting for the shed
Click to expand...
 
You ain't going to fit any smallish RCD consumer unit to a 13amp spur.
And there is no way your going to run tumble dryer/chest freezer/hifi/power tools/outside lighting/lighting for the shed off a spur.:eek:

Your looking at garage consumer unit with something like 1 x 63A 30mA RCD; 1 x 32A, 1 x 6A MCB's, with a supply taken a spare fuse way from your main consumer unit in your house.

Using a 32a MCB would allow you to have a ring main in the shed,( I always prefer a ring main) instead of a radial circuit.

And how far is it to the bottom of the garden, what size is the armoured cable & remember you need to comply with Part P.
 
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Nightglow said:
You ain't going to fit any smallish RCD consumer unit to a 13amp spur.
And there is no way your going to run tumble dryer/chest freezer/hifi/power tools/outside lighting/lighting for the shed off a spur.:eek:

Your looking at garage consumer unit with something like 1 x 63A 30mA RCD; 1 x 32A, 1 x 6A MCB's, with a supply taken from your main consumer unit in your house.
Click to expand...

Damnit.
The electrician has made some weird choices in this house to be fair.

Given what you have just said I can't see why he would have connected the cable to a fused spur, other than the fact the other end is currently still exposed and sticking up out of the floor at the bottom of the garden.

I can't see how I would get a feed direct from the main fusebox now (well not easily anyway)
 
Here I have a 45a MCB, in main consumer unit suppling power to a 10mm SWA connected to a consumer unit in my shed, which has 1 x 63A 30mA RCD; 1 x 32A, 2 x 6A MCB's.
 
supply from the fuse spur is probably assuming you would only want to use 1 socket and a light in the shed, so power tool or 1 x 13a appliance and lighting in the shed, they clearly haven't designed it for much more than that
 
HardwareGeek said:
supply from the fuse spur is probably assuming you would only want to use 1 socket and a light in the shed, so power tool or 1 x 13a appliance and lighting in the shed, they clearly haven't designed it for much more than that
Click to expand...

Is spot on, Which is why I asked those questions.

I'd have a word with your electrician, if he knew you were wanting to run what you say then I'd employ the services of a better electrician.

Nightglow is correct in what he is saying, sorry to say.
 
13A fuse will run over before it blows, so you wont blow at 13A more like 19A+ for instant blowing afaik 1.5x rating for HRC's to blow, pulling more than 13A load would heat up though and maybe damage spur eventually.
 
HardwareGeek said:
13A fuse will run over before it blows, so you wont blow at 13A more like 19A+ for instant blowing afaik 1.5x rating for HRC's to blow, pulling more than 13A load would heat up though and maybe damage spur eventually.
Click to expand...

Good point, OP That is the reason you should not use a standerd spur unit to protect anything you run out of the house, 19A for even a couple of seconds will do a lot of damage, you need to protect the cable going down the garden as the most likely failure is going to be something going through the cable (even armoured) normally someone who moves in after you who does not realise the cable is there so make sure you protect the whole curcuit with an RCD/RCBO and then protect the outside curcuits as well with a consumer unit and relevent RCD's

Also as other have said think about the current rating of your cable, a quick google will give you a rating of mm2
 
I bet the sparky hasn't even put the SWA at the correct depth!

As its coming of a spur from the main fuse board which will most likely be 13amp you will be fine to use the normal power tools etc just nothing to strenuous
 
Renton said:
You need to protect the cable going down the garden as the most likely failure is going to be something going through the cable (even armoured) normally someone who moves in after you who does not realise the cable
Click to expand...

I always try & bury a swa cable x1.5 the depth of a spade's blade, about 450mm minimum, preferably 600mm.

It avoids most of the accidents cutting through a cable.
 
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gijohn2 said:
I bet the sparky hasn't even put the SWA at the correct depth!
Click to expand...

That's only a recommendation, & not a legal requirement, I've seen swa put in at 75mm depth.:eek:

When I poured some new concrete steps here, I put a length of pipe in place, so I could run a swa cable through it, to some lights on hard standing, it went in at 800mm depth.
 
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Are you saying the "shed power" should have it's own MCB in the main fusebox ?

My logic says that if the fused spur is removed and the wire connected dirrectly then it will now be directly attached to some circuit coming from the main fuse board, the only thing I have no way of telling at this moment in time (without speaking to the sparky) is which MCB the wire has been wired to.

To be fair I want to run all the above stuff off it but not neccessarily at the same time, it sounds like so long as I don't do too much at the same time as drying clothes I should never have any problems. I don't spend a huge amount of time in the shed so can't really see it being a problem.

So all the above said (and assuming the fused spur cannot be changed) do I still need an RCD for the shed (at the shed end) if so can I buy one that is rated at 16A ? I only seem to see them rated at 32A+ :)
 
Yes.

The fused spur will be on the ring main, which has a 32a fuse in the main consumer unit.
All you can fit at the shed end is one double socket & a light.

Either your electrician doesn't know his job, or you didn't explain clearly your requirements to him for your electrics in the shed.
 
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Nightglow said:
Yes.

The fused spur will be on the ring main, which has a 32a fuse in the main consumer unit.


All you can fit at the shed end is one double socket & some lights.
Click to expand...

And I think that will actually be enough to be fair, the only real reason for me wanting to fit more sockets is convenience (ie not having to trail a wire accross the shed when I want to use a drill on the other side etc)
 
DogsBody said:
And I think that will actually be enough to be fair, the only real reason for me wanting to fit more sockets is convenience (ie not having to trail a wire accross the shed when I want to use a drill on the other side etc)
Click to expand...

I would say you can have more sockets for convenience like you say as long as you don't pull too much power, cant see a problem there.
 
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