In the process of purchasing a timber garage which will be used exclusively
as a workshop. I am trying to do as much as possible on my own and have just
finished compacting the hardcore prior to concrete pouring (yet to be
What I'd like to do now is dig a trench for a run of armoured cable from the
house to the workshop. I'd like to dig the trench and order the cable and
perhaps a CU?? for the workshop along with several metal sockets and the
internal wiring requirements. The workshop will require 1 strip light and 3
or 4 double sockets - mainly for power tools etc.
My plan is:
Dig a trench approx 600mm deep from house to workshop
After all this I'm going to contact an electrician to quote me for
connecting it all up to the CU in the house! (there are some things I am not
prepared to do at this stage in my quest to learn all things DIY!!). I
expect people to say "let the electrician get all this for you" but I'd
rather do it myself (pun?) - I feel I'll learn more this way ;o)
If anyone in their wisdom could check over my shopping list I'd appreciate
Yep, 450mm -600mm will be ample. Common sense really is all that's
needed, if its going somewhere where it's unlikely that there'll be a
shovel being shoved in the ground then 450mm will suffice.
It depends what size MCB it will be connected to at the house end, I'd
use the 4mm if it were me.
These are cheaper and do the same job.
Yep, looking ok there.
Nearly, you'll be wanting 1.0mm for the lights and 2.5mm for the
sockets. Might be cheaper for the electrician to supply this if you're
not going to need the whole lot.
Depends what you want, I'd use flourescent battens. Depending on the
layout I would conveniently site several smaller fittings rather than
a couple of large ones centrally.
None, SWA is perfectly fine for direct burial.
Ah, in that case with regard to the internal cabling for the workshop
then you may be better of buying what you need by the metre from a diy
store, depends what the saving is between that and buying complete
drums from screrwfix. You could always give the excess from the drums
to the electrician in exchange for a couple of quid off the bill!
It's probably worth you calling the electrician first to see what size
MCB\fuse is going to be fitted at the house end to size the SWA for
the run to the workshop, although 4mm should be fine for what you will
need in there.
This depends on how long the run is, and how much power you need at the
garage. What is the rating of the MCB in your main CU which is going to
feed the workshop? 32A?
I have used one of these in my shed. Very nice.
This gives an answer to the question I posed above. You'll need 3 core
4mm cable (14535).
Again, I've used these, and have no complaints.
This will be fine for the lights, but not at all suitable for the power
sockets. I would use 4mm T&E in a radia circuit.
Also think about a) how the cable will be protected, and b) how it will
enter/exit the metal socket cases. I'd suggest some 20mm round conduit
(screwfix 12389) and appropriate adaptors (screwfix 11010). Don't forget
clips for clipping it to the walls (screwfix 13093).
Fluorescent is good.
Don't forget a light switch.
Might it not be worth increasing the trench depth a little and burying 1 or
2 plastic drainage type pipes? From experience I know that these projects,
like Topsy, can just grow & grow!
Not too far hence you may want a LAN connection, or a phone line, or a
Just my tuppence worth
Indeed, or a little railway system to bring you things from the kitchen.
Beginning to wish I'd gone for more than 40mm conduit to the garage -
and it's empty at the moment.
I realise now that 60mm would have been far nicer to put water in.
With 2*2.5mm t+e (easier than pulling 6mm), 2* coax (satellite, and FM/UHF
(to resite dish and antennae)), it's getting a bit tight.
Not to mention that I meant to add, but forgot about some old 50 pair
phone cable, that might be handy.
50/60mm would have been lots easier.
Though this way of thinking tends to lead to the realisation that
it'd be much easier if you put in larger pipe, with internal lights, so you
could crawl into it and play with the cabling out of the rain.
"Ian Stirling" wrote
| > Not too far hence you may want a LAN connection, or a phone line,
| > or a water supply.
| Indeed, or a little railway system to bring you things from the kitchen.
| Though this way of thinking tends to lead to the realisation that
| it'd be much easier if you put in larger pipe, with internal lights,
| so you could crawl into it and play with the cabling out of the rain.
Add some barbed wire fences, searchlights and alsations roaming about the
garden to keep out the local lowlife ... Were you a prisoner-of-war in a
former life ;-)
I would suggest going for more than one light if you are going to be
using power tools in there. It helps if you have light from several
directions so that you never end up working in your shaddow.
Judging by the size of the base I would expect four or five 5' strip lights!
Off the top of my head (and thus in no particular order):
Place the workbench along the major axis of the building so that you can deal
with long lengths of (say) wood in any bench vice.
Twenty quid was the cost of a 700mm by 2400mm sheet of twinwall polycarbonate
that I bought a month or so ago to install in the flat roof above my own
workbench - you can't beat natural light.
The consumer unit will cover lights and sockets but some day you might want
to put (god forbid :-) a freezer in the building thus an RCD protected supply
might not be the best for such an appliance. So a small four-way consumer unit
might be better.
Run extra cables and/or a length of string in cheap 40mm drain piping along
with your mains supply cable to the workshop. Wrap the drain piping in some
stripey tape to warn the next punter whats in the pipe.
The extra cabling for alarm, intercom, wired network access, wired phone
extension, etc etc.
Use four-core for the mains feed - this allows switching of a separate line
from the house - you may want to switch a shed-mounted light from the house,
or you may want to switch off a shed-mounted PIR security light on a windy
night when the light switches on and off regularly.
Rainwater barrel to collect the runoff from the roof?
P.S. Silly question, but do you plan to bolt the shed to the concrete base?
If you dont, you run the risk of losing the shed when damaging storm winds
Add some anchor points before you pour the concrete?
Will you be using some sort of polythene membrane over the hardcore before
pouring the concrete?
Keep the hardcore about 50mm short of the shuttering boards so that the
concrete goes down the full face of the shuttering boards and thus it forms
a complete cap over the hardcore (when you remove the shuttering boards
you shouldn't be able to see hardcore at all).
I'd suggest running a plastic pipe with rope threaded through for stuff you think of
(phone, doorbell, network, TV aerial etc. etc....) - blue water pipe perhaps.
..and maybe water as well while you're at it....
I ran 4" soil to my workshop and it's now getting really hard to pull more stuff
I hope you aren't suggesting running a blue pipe across to the
workshop for the cables to go in, blue is for water, black is for
power, yellow is for gas, some other colours including green, purple
and grey are for communication cables.
Well, I was only saying there's a right way and there's your way! ;-)
I personally couldn't care less what you put under the garden, but
people come here to ask for the correct way of doing things, if they
didn't want to know how to do it properly, they wouldn't bother asking
in the first place.
I'm sure most people are after the most pragmatic solution, in terms of cost,
and a whole host of other criteria, and few would consider spending any additional
time, money or
effort to make something 'correct' just for the sake of being correct where there are
safety or other concerns.
If you do something like this in a non standard way then it can become
a safety issue for somebody coming along later who is not aware of
what was done.
For example, I could wire with live on the green and yellow wire and
neutral on the red. As long as I remember what has been done, then
there is no safety issue. Somebody else may have a different
I agree with Lurch on this point. If there is a standard published
way to do something, especially with electricity, it is there for a
reason and should be followed.
There are always bodges and generally the cost and effort between
doing a job properly and bodging it is very little.
Running power cables in blue water pipe can be described in no other
way than a bodge.
One is free to do whatever one likes as long as one is prepared to
accept the consequences.
To email, substitute .nospam with .gl
Of course I agree that this would be a clear safety issue, and should be done
I never suggested running power cables in blue pipe - the OP said he was running
armoured for power,
which I would agree with, and I suggested blue pipe for everything else : phone,
data etc., so
there is no safety issue.
In the overall case, placing warning tape above the trench would be far more
important than what
services were what colour, to alert any potential digger that there is 'something'
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