Wiring to shed

[paulfoel]

Shed in question is 10m away from house.

I was going to use armoured cable (6mm?) and just plug into socket in house and drill hole through wall. Route cable along garden fence, into shed, into plug socket.

In shed all I need to power is strip light and small freezer.

Is this safe to do? i.e. use plug socket. Or am I better getting electrician to do this?

[The Natural Philosopher]

I'd be inclined to patch into a fresh RCBO on the CU, or at the very
least into an RCBO equipped spur.


--
Ineptocracy

(in-ep-toc’-ra-cy) – a system of government where the least capable to
lead are elected by the least capable of producing, and where the
members of society least likely to sustain themselves or succeed, are
rewarded with goods and services paid for by the confiscated wealth of a
diminishing number of producers.

[polygonum]

On 06/10/2012 13:05, The Natural Philosopher wrote:
> paulfoel wrote:
>> Shed in question is 10m away from house.
>>
>> I was going to use armoured cable (6mm?) and just plug into socket in
>> house and drill hole through wall. Route cable along garden fence,
>> into shed, into plug socket.
>>
>> In shed all I need to power is strip light and small freezer.
>>
>> Is this safe to do? i.e. use plug socket. Or am I better getting
>> electrician to do this?
>>
>>
> I'd be inclined to patch into a fresh RCBO on the CU, or at the very
> least into an RCBO equipped spur.
>
>

Do you mean having a plug at BOTH ends of the cable? I hope not, but it
is not, to me, 100% clear.

--
Rod

[Tim Watts]

You could - although I'd be inclined to use a FCU (Fused Spur).

You *must* have the cable protected by RCD though.

I would have thought 2.5mm2 would be more than adequate at 10m length - I
can double check this (current rating is fine at 13A max but volt drops are
worth considering).


--
Tim Watts Personal Blog: http://www.dionic.net/tim/

"She got her looks from her father. He's a plastic surgeon."

[paulfoel]

> Do you mean having a plug at BOTH ends of the cable? I hope not, but it
>
> is not, to me, 100% clear.
>

Plug into socket in house. Cable to garage going into socket. Plug into this.

Not cool?

[paulfoel]

> I'd be inclined to patch into a fresh RCBO on the CU, or at the very
>
> least into an RCBO equipped spur.
>

Lost me :-(

[paulfoel]

On Saturday, October 6, 2012 1:22:19 PM UTC+1, Tim Watts wrote:
> paulfoel wrote:
>
>
>
> > Shed in question is 10m away from house.
>
> >
>
> > I was going to use armoured cable (6mm?) and just plug into socket in
>
> > house and drill hole through wall. Route cable along garden fence, into
>
> > shed, into plug socket.
>
> >
>
> > In shed all I need to power is strip light and small freezer.
>
> >
>
> > Is this safe to do? i.e. use plug socket. Or am I better getting
>
> > electrician to do this?
>
>
>
> You could - although I'd be inclined to use a FCU (Fused Spur).
>
>
>
> You *must* have the cable protected by RCD though.
>
>
>
> I would have thought 2.5mm2 would be more than adequate at 10m length - I
>
> can double check this (current rating is fine at 13A max but volt drops are
>
> worth considering).
>

So if I plug into socket in house (with RCD plug) this is OK? As you can see an electrician I am not....

[meow...@care2.com]

Yes, but you'd need to use a more sensible cable size, 6mm^2 won't have any chance of fitting a mains plug. Its not an ideal setup, but will do the job, with rcd protection.


NT

[John Rumm]

On 06/10/2012 13:02, paulfoel wrote:
> Shed in question is 10m away from house.
>
> I was going to use armoured cable (6mm?) and just plug into socket in
> house and drill hole through wall. Route cable along garden fence,
> into shed, into plug socket.

Can't see you needing 6mm for this...

> In shed all I need to power is strip light and small freezer.

In which case a circuit designed to support 13A of total load would be
more than adequate.

If there is already a RCD[1] protecting the circuit, then fit a fused
spur unit with a double pole switch. Drill a hole out the back of this
through the wall. On the outside of the wall stick either a water prrof
junction box or an external socket. Connect the SWA cable to this
(2.5mm^2 two core will do) using an exterior grade gland[2]. Connect the
junction box to your switched FCU with some normal 2.5mm^2 T&E cable.
Run that to the shed and either repeat the trick with the junction box
or take the whole SWA into the shed. Terminate that using a gland into a
surface mounted metal clad double socket. Stick another metalclad
switched FCU beside that with a 3A fuse in, and use that to power the
light. (it can double as a light switch if you want).

> Is this safe to do? i.e. use plug socket. Or am I better getting
> electrician to do this?

Have a read through this:

http://wiki.diyfaq.org.uk/index.php?title=Taking_electricity_outside

[1] http://wiki.diyfaq.org.uk/index.php?title=RCD

[2] http://wiki.diyfaq.org.uk/index.php?title=Terminating_SWA

--
Cheers,

John.

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

[Andrew Gabriel]

In article <2ed43b97-f136-4845...@googlegroups.com>,

meow...@care2.com writes:
>
> Yes, but you'd need to use a more sensible cable size, 6mm^2 won't have any chance of fitting a mains plug. Its not an ideal setup, but will do the job, with rcd protection.

No SWA cable will go in a mains plug. You need to join to a
1.25mm² or 1.5mm² flex to make the connection to the plug.
Use a straight-through metal BESA box with an SWA gland in
one side to terminate the SWA cable, and a 20mm cable gland
to grip the flex on the other side. The BESA box needs to be
earthed internally, to provide the earthing for the armour.

I'd really have to question if the OP is going to be up to
connecting this all up correctly, most particulary the
earthing, given the questions. We haven't even discussed
things like exporting earths or not, what type of earthing
system the house is, what RCD protection the house has, how
to split off the lighting circuit in the shed, etc. I would
strongly suggest getting someone competent involved to do it
or check it all out.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

[meow...@care2.com]

On Saturday, October 6, 2012 5:33:09 PM UTC+1, Andrew Gabriel wrote:
> In article <2ed43b97-f136-4845...@googlegroups.com>,

> meow2222 writes:

> I'd really have to question if the OP is going to be up to
> connecting this all up correctly, most particulary the
> earthing, given the questions.

That's very simple

> We haven't even discussed
> things like exporting earths or not, what type of earthing
> system the house is, what RCD protection the house has, how
> to split off the lighting circuit in the shed, etc. I would
> strongly suggest getting someone competent involved to do it
> or check it all out.

I'm not convinced any of that is particularly significant in safety terms


NT

[polygonum]

Much cooler than the very dangerous bodge of putting a plug at both ends
and using that to power up a circuit in the shed/garage. And not far off
what I have done. We only need light, a fan and a laptop charger.

The house end uses a plug-cum-RCD.

--
Rod

[Tim Watts]

paulfoel wrote:

> So if I plug into socket in house (with RCD plug) this is OK? As you can
> see an electrician I am not....

Half the population would run a bit of extension lead down the garden in the
grass or ties to rusty nails along the fence.

At least you are proposing armoured cable and RCD protection, so you're on
the winning team to start with :)

It comes down to physics, and a bit of common sense:

1) The RCD will detect any fault to earth > 30mA and trip in less than 40mS
- these are to do with the probability of the human body staying alive after
such a shock.

2) The RCD will also give you enhanced fault protection for faults to earth
- not wholly relying on the fuse to blow - this can be a problem with very
long cables, but 10m is not that long.

3) You've only got a 13A circuit with a very low expected load at the other
end.

There are some deeply weird technical considerations to do with what they
call "exporting the earth" from the house to an outbuilding, but these are
only a serious concern with metal buildings where the house earth will be
bonded to the metal of the building[1] or similar cases. Assuming you are
talking wooden shed and not metal greenhouse, not really a problem.



Correction on cable size: I am not an encylopedia, so I checked:

http://www.tlc-direct.co.uk/Technical/Charts/VoltageDrop.html

1.5mm2 3 core armoured would be more than adequate at 13A (3kW in the web
page form above).

Worst voltage drop is 3.26V which is neglible and the cable is fine for 13A.


I think the only remaining bit you may need help with is terminating the
armoured cable and making sure the armour is bonded to the earth core at
both ends.

You can use 2 core armoured and use the armour as the earth core (in fact
this is typical) but there's not much in the cost and my incination is to go
for 3 core because if one of your terminations is weak, you will not not
lose integretity of the earth.


HTH

Tim



[1] Under some very weird fault cases, the house earth could rise to some
highish voltage above the actual wet ground outside. Inside the house this
is not a problem (mostly) as metal pipes and Class I (earthed) appliance all
rise together due to the bonding - so there is no potential difference to
stick yourselve across. However, if you cause your greenhouse to rise to
100V above the wet ground next to it, you have a problem.

--
Tim Watts Personal Blog: http://www.dionic.net/tim/

"A fanatic is one who can't change his mind and won't change the subject."

[Tim Watts]

I think the making off of the cable would be his biggest issue. It's not
fantascially hard for someone used to doing minor electrical works, but I
don't know what the OP is like.


There are pre-made kits which amount to basically the same thing, but all
the connections are already done for you and it's all nicely sealed - which
might be a good option:

http://www.primrose.co.uk/-p-2322.html

I know it's out of stock, but it gives the OP something to google for. Had a
feeling B&Q etc sometimes carry something like this?

Cheers,

Tim

--
Tim Watts Personal Blog: http://www.dionic.net/tim/

[paulfoel]

> Half the population would run a bit of extension lead down the garden in the
>
> grass or ties to rusty nails along the fence.
>
>
>
> At least you are proposing armoured cable and RCD protection, so you're on
>
> the winning team to start with :)
>
>
>
> It comes down to physics, and a bit of common sense:
>
>
>
> 1) The RCD will detect any fault to earth > 30mA and trip in less than 40mS
>
> - these are to do with the probability of the human body staying alive after
>
> such a shock.
>
>
>
> 2) The RCD will also give you enhanced fault protection for faults to earth
>
> - not wholly relying on the fuse to blow - this can be a problem with very
>
> long cables, but 10m is not that long.
>
>
>
> 3) You've only got a 13A circuit with a very low expected load at the other
>
> end.
>
>
>
> There are some deeply weird technical considerations to do with what they
>
> call "exporting the earth" from the house to an outbuilding, but these are
>
> only a serious concern with metal buildings where the house earth will be
>
> bonded to the metal of the building[1] or similar cases. Assuming you are
>
> talking wooden shed and not metal greenhouse, not really a problem.
>

Tim - thanks....

Its a wooden shed so I guess I'm OK.

[paulfoel]

> I think the making off of the cable would be his biggest issue. It's not
>
> fantascially hard for someone used to doing minor electrical works, but I
>
> don't know what the OP is like.
>
>
>
>
>
> There are pre-made kits which amount to basically the same thing, but all
>
> the connections are already done for you and it's all nicely sealed - which
>
> might be a good option:
>
>
>
> http://www.primrose.co.uk/-p-2322.html
>
>
>
> I know it's out of stock, but it gives the OP something to google for. Had a
>
> feeling B&Q etc sometimes carry something like this?
>

Plan is:-

RCD plug in house
Armoured cable runs through hole in wall
Into waterproof socket via cable gland

Another armoured cable with plug on end.
Runs 10m into garage
Into normal socket box.

Am I right in saying that even if I use 2.5mm armoured cable I still might have an issue with the electrical connections? Its not as simple as standard electrical cable?

[paulfoel]

Would this sort of thing do?

http://www.joesaquaticworld.co.uk/blagdon-powersafe-armoured-supply-kit-15-mt.html

[Tim Watts]

paulfoel wrote:

> Am I right in saying that even if I use 2.5mm armoured cable I still might
> have an issue with the electrical connections? Its not as simple as
> standard electrical cable?

No it's not.

http://www.youtube.com/watch?v=ZFnNDuCSz-8

That's slightly different to the usual sort of gland, but the making off
process is basically very similar.

Then you should bond both glands (one at each end) to the earth wire using a
"banjo" tag (included) or Piranha nut (optional extra):

http://www.tlc-direct.co.uk/Products/TLB20S.html

(buy the right size of gland for the cable!)

If you do not bond the armouring wires to earth, you gain no real advantage
of using SWA cable.

--
Tim Watts Personal Blog: http://www.dionic.net/tim/

"History will be kind to me for I intend to write it."

[Tim Watts]

Yep - at that price it would not be too much worse than amassing the bits.

All you need to do is bury the armoured cable the right way:

more than 2 (3 in a flower bed) spade's down is a good guideline, the soil
must be free of large stones - either sieve a bit of soil back or line with
soft sand.

Half bury, cover with supplied warning tape and complete burying (so tape is
found well in advance of someone is digging).

Or you can put a line of bricks or paving stones over the cable route then
the tape for extra robustness.

The leaflet suggests clipping the cable to a rank old wooden fence - do not
do this, it is a crap idea - fences fall over. Brick walls are OK though.

But basically, your hardest job becomes the digging if you need to bury it.

[John Rumm]

On 08/10/2012 11:28, paulfoel wrote:
>
>> I think the making off of the cable would be his biggest issue.
>> It's not
>>
>> fantascially hard for someone used to doing minor electrical works,
>> but I
>>
>> don't know what the OP is like.
>>
>>
>>
>>
>>
>> There are pre-made kits which amount to basically the same thing,
>> but all
>>
>> the connections are already done for you and it's all nicely sealed
>> - which
>>
>> might be a good option:
>>
>>
>>
>> http://www.primrose.co.uk/-p-2322.html
>>
>>
>>
>> I know it's out of stock, but it gives the OP something to google
>> for. Had a
>>
>> feeling B&Q etc sometimes carry something like this?
>>
>
> Plan is:-
>
> RCD plug in house Armoured cable runs through hole in wall Into
> waterproof socket via cable gland
>
> Another armoured cable with plug on end.

You can't put a plug on the end of armoured cable. Firstly its too thick
to go in the plug, and secondly you have no way of terminating the earth
(armour wires).

> Am I right in saying that even if I use 2.5mm armoured cable I still
> might have an issue with the electrical connections? Its not as
> simple as standard electrical cable?

See the link I posted elsewhere on SWA terminations.

[paulfoel]

Cheers Tim. Bought this kit now. Seems the easiest and safest option LOL.

[ARW]

As the OP is not buring the cable why not use Hi Tuff cable?

--
Adam

[John Rumm]

On 08/10/2012 18:02, ARW wrote:

>> See the link I posted elsewhere on SWA terminations.
>
> As the OP is not buring the cable why not use Hi Tuff cable?

That could work, although I expect it would still be a bugger to get
into a plug.