I'm about to decorate our dining room, the final step of which will be to
lay some new wooden flooring in the room and hall. Before this is done I
would like to run some trunking from the cupboard under the stairs, where
the CU is, to the back wall of the house so that I can run power to the
garden at some point in the future. It's a straight run from the cupboard
to the outside wall - just over 4 metres. I was planning to fix some
trunking under the floorboards (joists run in the right direction) and drill
a hole through the wall (house c1905, no cavity), covered with a suitable
wallbox, until such a time as I get around to needing to draw cable and get
things wired up. No intention of doing any electrical work at this time.

Are there any special requirements I need to be aware of and what sort of
trunking should I be using?

Thanks in advance.

Mark

Mark Walters wrote:
I'm about to decorate our dining room, the final step of which will be to
lay some new wooden flooring in the room and hall. Before this is done I
would like to run some trunking from the cupboard under the stairs, where
the CU is, to the back wall of the house so that I can run power to the
garden at some point in the future. It's a straight run from the cupboard
to the outside wall - just over 4 metres. I was planning to fix some
trunking under the floorboards (joists run in the right direction) and drill
a hole through the wall (house c1905, no cavity), covered with a suitable
wallbox, until such a time as I get around to needing to draw cable and get
things wired up. No intention of doing any electrical work at this time.

Are there any special requirements I need to be aware of and what sort of
trunking should I be using?

If it's under the floorboards, why do you want to use trunking at all?
Can't you just lay the cable under the floor, with both ends suitably
isolated and marked up clearly as to what they are, so that you or
somebody else in X years' time will know what the cable is?

David

"Lobster" wrote in message
...
Mark Walters wrote:
I'm about to decorate our dining room, the final step of which will be
to
lay some new wooden flooring in the room and hall. Before this is done
I
snip
things wired up. No intention of doing any electrical work at this time.

Are there any special requirements I need to be aware of and what sort
of
trunking should I be using?

If it's under the floorboards, why do you want to use trunking at all?
Can't you just lay the cable under the floor, with both ends suitably
isolated and marked up clearly as to what they are, so that you or
somebody else in X years' time will know what the cable is?

Good point. As I don't know enough about the requirements for outside
wiring I just want to make sure that there is some way to install the cables
without having to lift the floor. If I did run T&E and leave it unconnected
what size would be appropriate - the run down the garden could be up to 60
metres?

Mark

Mark Walters wrote:
"Lobster" wrote in message
...

Mark Walters wrote:

I'm about to decorate our dining room, the final step of which
will be to lay some new wooden flooring in the room and hall.
Before this is done

If it's under the floorboards, why do you want to use trunking at
all? Can't you just lay the cable under the floor, with both ends
suitably isolated and marked up clearly as to what they are, so
that you or somebody else in X years' time will know what the cable
is?

Good point. As I don't know enough about the requirements for
outside wiring I just want to make sure that there is some way to
install the cables without having to lift the floor. If I did run
T&E and leave it unconnected what size would be appropriate - the run
down the garden could be up to 60 metres?

Ah - running power "down" the garden, as opposed to "to" the garden as
you said in your original post - that's a bit different.

Power "to" the garden suggests a waterproof socket on the outside wall
of your house, wired directly using standard cable used for an ordinary
ringmain inside. No exposed cable.

Power "down" the garden is a whole different ball game, as you
suspected, for which you need special armoured cable, and there are alls
sorts of other consideration. However, at this stage, I wouldn't have
thought that's a problem, because you wouldn't be running armoured cable
all the way back to the CU anyway. Somebody else will along soon to
advise you better, this is now out of my comfort zone! but I would have
thought what you should be aiming at now would just be to get ordinary
T&E as far as a special junction box (a metal adaptable box?) inside the
house close to where the armoured cable will exit through the wall for
the garden.

Either way, for 'future-proofing' you want to install T&E under your
floor, to the same position.

David

"Lobster" wrote in message
...
Mark Walters wrote:
"Lobster" wrote in message
...

Mark Walters wrote:

I'm about to decorate our dining room, the final step of which
will be to lay some new wooden flooring in the room and hall.
Before this is done

If it's under the floorboards, why do you want to use trunking at
all? Can't you just lay the cable under the floor, with both ends
suitably isolated and marked up clearly as to what they are, so
that you or somebody else in X years' time will know what the cable
is?

Good point. As I don't know enough about the requirements for
outside wiring I just want to make sure that there is some way to
install the cables without having to lift the floor. If I did run
T&E and leave it unconnected what size would be appropriate - the run
down the garden could be up to 60 metres?

Ah - running power "down" the garden, as opposed to "to" the garden as
you said in your original post - that's a bit different.

Power "to" the garden suggests a waterproof socket on the outside wall
of your house, wired directly using standard cable used for an ordinary
ringmain inside. No exposed cable.

Power "down" the garden is a whole different ball game, as you
suspected, for which you need special armoured cable, and there are alls
sorts of other consideration. However, at this stage, I wouldn't have
thought that's a problem, because you wouldn't be running armoured cable
all the way back to the CU anyway. Somebody else will along soon to
advise you better, this is now out of my comfort zone! but I would have
thought what you should be aiming at now would just be to get ordinary
T&E as far as a special junction box (a metal adaptable box?) inside the
house close to where the armoured cable will exit through the wall for
the garden.

Either way, for 'future-proofing' you want to install T&E under your
floor, to the same position.

David


As Mr Lobster says, "There is a lot more to running electricity to an
outside point" so listen up. What are you proposing to run at the other end
of the cable? If it's an outhouse or garden office, then you really need to
do a full sub-mains installations for it to be safe and to pass your local
council testing certification.

If you want a double socket for the pond pump and a couple of small lights,
then you need to place armoured cable to a weather tight box that is removed
from the ground on proper non-corrosive supports, and lifted to a minimum
height of 300 millimetres. A length of 60 Metres will mean you'd need in
the region of a 4 mm *csa' to 6 mm *csa' cable to properly supply a double
socket without losses, safely.

For an outbuilding or garden office, then this will all depend on what you
are placing in and around the build. For a proper outbuilding workshop
area, then you need to run a totally separate sub-mains supply from a
totally separate isolator switch at your present electrical supply head end.
The cable itself will probably need to be in region of a 16 mm *csa' to 25
mm *csa', dependant on the total power you need at the outhouse. This is
not a job for a DIYer, as there is much more to it than just getting power
to the building. It also involves safety earth loops and safety drop-out
gear to be properly and safely used. These all need to pass strict testing
before they are passed on to you by any contractor.

Get back with your needs and I'll try to help further, if you wish. I am
quite busy at the moment, so please allow me at least a day to reply.

*csa' = cross sectional area of the cable conductors

"BigWallop" wrote in message
. uk...

"Lobster" wrote in message
...
Mark Walters wrote:
"Lobster" wrote in message
...

Mark Walters wrote:

I'm about to decorate our dining room, the final step of which
will be to lay some new wooden flooring in the room and hall.
Before this is done

If it's under the floorboards, why do you want to use trunking at
all? Can't you just lay the cable under the floor, with both ends
suitably isolated and marked up clearly as to what they are, so
that you or somebody else in X years' time will know what the cable
is?

Good point. As I don't know enough about the requirements for
outside wiring I just want to make sure that there is some way to
install the cables without having to lift the floor. If I did run
T&E and leave it unconnected what size would be appropriate - the run
down the garden could be up to 60 metres?

Ah - running power "down" the garden, as opposed to "to" the garden as
you said in your original post - that's a bit different.

snip
Either way, for 'future-proofing' you want to install T&E under your
floor, to the same position.

David


As Mr Lobster says, "There is a lot more to running electricity to an
outside point" so listen up. What are you proposing to run at the other
end
of the cable? If it's an outhouse or garden office, then you really need
to
do a full sub-mains installations for it to be safe and to pass your local
council testing certification.

I don't expect that the requirement at the far end will be for any more
than;

* a couple of sockets for domestic garden kit such as lawn mower, hedge
trimmer

* lighting for shed/greenhouse - single fluorescent tube or similar

* automated vents for small greenhouse

* small number of garden lights

If you want a double socket for the pond pump and a couple of small
lights,
then you need to place armoured cable to a weather tight box that is
removed
from the ground on proper non-corrosive supports, and lifted to a minimum
height of 300 millimetres. A length of 60 Metres will mean you'd need in
the region of a 4 mm *csa' to 6 mm *csa' cable to properly supply a double
socket without losses, safely.

That's the tye of setup was envisaging, with the armoured cable terminating
in the shed.

For an outbuilding or garden office, then this will all depend on what you
are placing in and around the build. For a proper outbuilding workshop
area, then you need to run a totally separate sub-mains supply from a
totally separate isolator switch at your present electrical supply head
end.
The cable itself will probably need to be in region of a 16 mm *csa' to 25
mm *csa', dependant on the total power you need at the outhouse. This is
not a job for a DIYer, as there is much more to it than just getting power
to the building. It also involves safety earth loops and safety drop-out
gear to be properly and safely used. These all need to pass strict
testing
before they are passed on to you by any contractor.

Nothing that significant.

Get back with your needs and I'll try to help further, if you wish. I am
quite busy at the moment, so please allow me at least a day to reply.

Thanks for the offer. I don't intend to attempt the outside work myself as
it's well beyond anything I could do safely. What I do want to do is to
make sure that I have the necessary bits in place internally to enable the
above without having to lift the floor to run cable to the CU.

Mark

"Mark Walters" wrote in message
. ..

"BigWallop" wrote in message
. uk...

snipped

Thanks for the offer. I don't intend to attempt the outside work myself
as
it's well beyond anything I could do safely. What I do want to do is to
make sure that I have the necessary bits in place internally to enable the
above without having to lift the floor to run cable to the CU.

Mark



How far from the outside wall is the current mains head end? Wire-Armoured
cable is quite rigid, and it can be pushed quite easily for long distances
under floor voids and things. You do need a tight fitting cap on the end,
two layers of insulating tape wrapped tight, to stop it catching debris, but
it is possible to get a 10 mm csa' SWA(steel wire armoured) Cable to travel
long distances in gaps under floor voids. Easily 3 to 4 metres or more.

So, if you only have a short distance to travel under the floor, then you'd
probably only need to lift a small bit of floor in the cupboard where the
head end is, and push the cable through the wall toward it. Enough hole in
the floor to get an arm through to feel for the cable should be enough. Or
get your head in with a big torch to make life really easy.