Hi everyone,

I have the following situation currently:

I have a 13A fused spur going in metal conduit for about 2 metres to a
brick shed. Within that shed I have a 5A fused connection to a
fluorescent light and then three power sockets (computer equipment, low
power usage).

What I would like to do is as follows:

Extend the connection from the furthest power point in the brick shed for
about 25 metres using SWA cable (how far down does SWA cable need to be
dug, AFAIK non-SWA needs 1/2 metre - how about SWA?) to a new wooden shed.
Inside that shed have two fluorescent lights and a number of power sockets.

I know I'm going to be limited to 13A total usage for the whole outside
(due to the fused spur) which is fine - I'll either be in the woodworking
shop or in the "office", not both at the same time.

Any problems aside from this? I need to get an electrician to certify the
work, correct (as Part P covers outside electrics)? No problems with the
length? Can I actually do the work myself and just have him certify it's
connected OK? What would he need to see to certify (can he just check the
connection end or will he need to see the wiring to every circuit in the
shed)?


Cheers,


Andy


--
Andy Jeffries | gPHPEdit Lead Developer
http://www.gphpedit.org | PHP editor for Gnome 2
http://www.andyjeffries.co.uk | Personal site and photos

Andy Jeffries wrote:

I know I'm going to be limited to 13A total usage for the whole outside
(due to the fused spur) which is fine - I'll either be in the woodworking
shop or in the "office", not both at the same time.

A single 13 A supply from a fused spur does not sound adequate for
something described as a "woodworking shop," unless you're only using
hand tools or small portable power tools. You didn't say how large the
brick shed is but you're likely to need 200+ W of fluorescent lighting,
~2 kW of electric heating in winter, plus any fixed machinery and dust
extraction. Even if the total load comes in under 13 A you may find
that motor starting currents give problems, blowing the 13 A fuse at the
house end, plunging the whole works into darkness and taking your
computer equipment off supply.

In fact the fused spur sounds just about OK for your office alone. The
workshop, unless very small-scale, really needs its own submain circuit
from the meter in the house.

--
Andy

On Mon, 16 Jan 2006 15:56:06 +0000, Andy Wade wrote:
I know I'm going to be limited to 13A total usage for the whole outside
(due to the fused spur) which is fine - I'll either be in the
woodworking shop or in the "office", not both at the same time.

A single 13 A supply from a fused spur does not sound adequate for
something described as a "woodworking shop," unless you're only using hand
tools or small portable power tools. You didn't say how large the brick
shed is but you're likely to need 200+ W of fluorescent lighting, ~2 kW of
electric heating in winter, plus any fixed machinery and dust extraction.
Even if the total load comes in under 13 A you may find that motor
starting currents give problems, blowing the 13 A fuse at the house end,
plunging the whole works into darkness and taking your computer equipment
off supply.

In fact the fused spur sounds just about OK for your office alone. The
workshop, unless very small-scale, really needs its own submain circuit
from the meter in the house.

OK, I'll give a sort of answer then ask a question...

The current brick shed has the powertools in it or run from an extension
from there (to be used outdoors) and the fuse never blows. The powertools
aren't industrial things, but small home-workshop type tools. The biggest
things are a 1500W saw (peak I'm assuming) and a 1300W router. They are
never used simultaneously.

Anyway, on to the question. How much do you think it would cost (ballpark
is fine) for a new submain circuit? 25 metre SWA cable run dug by me
(but would now need to be 2x cable length for ring, right). Need say 5
electrical sockets, 2 lights at far end. Ring comes from house wich is
about 28 metres from the shed (brick shed takes 2 metres, plus 1 metre of
metal conduit to house). From that wall there is the kitchen (cables can
be run behind cupboards) then the utility room with the consumer unit in
it.

I know nobody would give a fixed price over the net for something like
this, just after a ballpark. Hundred quid? Couple of hundred quid? A
thousand? I'm just after an idea so I know how feasible this is now I've
got my heart set on it... :-(

Cheers,



--
Andy Jeffries | gPHPEdit Lead Developer
http://www.gphpedit.org | PHP editor for Gnome 2
http://www.andyjeffries.co.uk | Personal site and photos

If I were you I would run 6mm x 3core SWA from the main building to the
first outhouse. In this building install a small metalclad consumer
unit with rcd protected circuits, as a first step.
Then,loop out again to the remote outbuilding in the same type of
cable,terminating at a second consumer unit like the other one.I should
do all the "donkey work" yourself like digging the trenches and
mounting the consumer units on the wall and then employ an electrician
to run a main in through the house to connect to your new cable via a
suitable main switch. Making off swa glands is not reccomended unless
youv'e had previous experience. This will stand you in good stead for
any further expansion of the "garden empire"
Look on ebay for good deals of swa cable.It needs to be buried 18''
minimum.

Andy Jeffries wrote:

Anyway, on to the question. How much do you think it would cost (ballpark
is fine) for a new submain circuit? 25 metre SWA cable run dug by me
(but would now need to be 2x cable length for ring, right). Need say 5

No, the submain would be a single cable run...

electrical sockets, 2 lights at far end. Ring comes from house wich is
about 28 metres from the shed (brick shed takes 2 metres, plus 1 metre of
metal conduit to house). From that wall there is the kitchen (cables can
be run behind cupboards) then the utility room with the consumer unit in
it.

There is no need to take SWA all the way to the CU in the house - you
can revert to T&E for the internal run.

I know nobody would give a fixed price over the net for something like
this, just after a ballpark. Hundred quid? Couple of hundred quid? A
thousand? I'm just after an idea so I know how feasible this is now I've
got my heart set on it... :-(


Well depends a bit on what you already have on the house CU... If there
is a spare way you could populate it with say a 30A HRC fuse in a
carrier, run 6mm^2 T&E through the house to a box where you could go to
SWA and drop out though the wall and to the shed. Say 70 quid for that lot.

At the shed you could stick in a small CU with a couple of ways with 20A
and 6A MCBs for power and lighting circuits, add an earth rod and a RCD
so as to make the shed a TT instalation (i.e. not using the house
earth). Say another £50 for that lot. Add on the costs of any sockets
and lights etc you want in the shed.

So all in you ought to be able to DIY for under £200 in materials (i.e.
ignoring the cost of your time and any associated with any part p nonsense)


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/