Garage Power Question


Postby Purple » Wed Jul 18, 2007 6:42 pm

Hi All

Read a few posts on this subject and digested much however, there are still a few question marks. Whilst I have no intention of doing this work myself, I would like to run power to my garage, which is detached from the house.


[b]Where I currently am[/b] - with a few basic tests I've established that the downstairs ring is protected by an RCD (stamped 80A ~30mA) so I'm hoping I can spur off a kitchen socket. The cable distance is likely to be about 40 metres.

[b]What I hope to do[/b] - run a spur from a kitchen socket with some armoured cable (buried) to the garage and have a second smaller CU with its own RCD and MCB for lights and power. I'm likely to want to run a fridge, a freezer and a few other small items like a battery charger and maybe a PC

[b]What do I need[/b] - Whilst I'm not going to undertake the work myself I'd like to source some or all of the components, as I think I can get them cheaper by shopping around. My main question is the armoured cable. Given the distance and power requirements, what would the recommendation in terms of core size?

Any other issues I've not foreseen welcome too!

Many thanks all[/code]
Purple
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Postby BLAKEY1963 » Thu Jul 19, 2007 10:33 pm

[quote="Purple"]Hi All

Read a few posts on this subject and digested much however, there are still a few question marks. Whilst I have no intention of doing this work myself, I would like to run power to my garage, which is detached from the house.


[b]Where I currently am[/b] - with a few basic tests I've established that the downstairs ring is protected by an RCD (stamped 80A ~30mA) so I'm hoping I can spur off a kitchen socket. The cable distance is likely to be about 40 metres.

[b]What I hope to do[/b] - run a spur from a kitchen socket with some armoured cable (buried) to the garage and have a second smaller CU with its own RCD and MCB for lights and power. I'm likely to want to run a fridge, a freezer and a few other small items like a battery charger and maybe a PC

[b]What do I need[/b] - Whilst I'm not going to undertake the work myself I'd like to source some or all of the components, as I think I can get them cheaper by shopping around. My main question is the armoured cable. Given the distance and power requirements, what would the recommendation in terms of core size?

Any other issues I've not foreseen welcome too!

Many thanks all[/code][/quote]

PURPLE
FIRST OF I DO ACKNOWLEDGE U R NOT DOING THIS WORK
YOUR SLEF.
GOING BY YOUR STATEMENT, WITH A 40 METRE RUN FROM THE
HOUSE FEEDING YOUR FRIDGE, FREEZER , A FEW OTHER SMALL
ITEMS SUCH AS BATTERY CHARGER , PC , AND GARAGE LIGHTING, YOU
WOULD NEED MORE THAN A 13 AMP SPUR OFF YOUR KITCHEN RING
YOU WOULD BE LOOKING AT A MINIMUM OF A 20 AMP RADIAL CIRCUIT
FOR YOUR SOCKETS AND 6 AMP FOR LIGHTING AS U SPECIFY SMALL
C U WITH RCD AND MCB S FOR LIGHTS AND POWER. SO A 30 AMP
SUPPLY WOULD BE MORE REALISTIC AND COMING DIRECT FROM YOUR
MAINS BOARD IN THE HOUSE. THIS PROBALY INCREASES THE RUN
SO AT LEAST A 10 MM2 ARMOURED WOULD HAVE TO BE LOOKED AT.
OBVIOUSLY THIS IS GOING BY YOUR INFO, THE BEST THING TO DO
GET A FREE QUOTATION FROM YOUR PART P SPARKY ( MOST BONA FIDE
WILL GLADLY ADVISE FREE OF CHARGE ) .
FAIR COMMENT U WANT TO GET MATERIALS , ASK SPARKY TO GIVE U
A LABOUR CHARGE ONLY QUOTATION.( OBVIOUSLY MATERIAL PURCHASED MUST BE TO BS 7671 ) SEE HOW U GET ON .
BLAKEY1963
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Postby sparx » Thu Jul 19, 2007 10:49 pm

Hi Purple,
You can run as you say bearing in mind total load on a ring only 32A, so would be better if u could run from CU in pvc/pvc tw/e then change to swa but I know not always practical to do.
Main ? would be load/distance as you note, If u could limit total load to 13A [fridge/freezer abt 3A each] PC negledgable but printer abt 5A
Average there less than 13A. then you could run via a fused spur from ring, this would give isolation point in house.
What u gonna do come winter? got a 'super ser' gas heater?
Anyway 13A X 40Mtrs X 11mV /1000 = 5.72Volts dropped if using a 4mm2 swa, plus some volts dropped in ring should still be in spec.
If no water/gas services in garage then you could run 3core wsa & rely on earth from house plus house RCD using swa+ 3rd core & go direct to sockets, then to FCU,with 3A fuse for lights.
However much better to run 2core swa, earthed only at house end, then fit RCD CU in garage with own earth rod [T.T.]
On a final note I doubt very much u will get swa cheaper than your Part P leckie can! I look in all 'sheds', catalogues, etc , & laugh at quoted prices I would never get any work if I paid those prices!!!
Regards SPARX
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Postby Purple » Fri Jul 20, 2007 7:32 pm

Cheers Guys

Some more questions - please excuse my ignorance.

First off, some acronym deciphering... swa, "pvc/pvc tw/e", "T.T." help?!

Secondly some clarification - realistically, I would run 1 freezer, 1 fridge, 1 PC (prob laptop so no monitor and no printer), lighting for single garage, occasional battery charger.

Thirdly - SPARX, not sure what you mean re winter? For clarification, I have no plans to use electrical heating in the garage.

Thanks for the advice guys - very much appreciated.
Purple
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Postby Purple » Fri Jul 20, 2007 7:34 pm

Cheers Guys

Some more questions - please excuse my ignorance.

First off, some acronym deciphering... swa, "pvc/pvc tw/e", "T.T." help?!

Secondly some clarification - realistically, I would run 1 freezer, 1 fridge, 1 PC (prob laptop so no monitor and no printer), lighting for single garage, occasional battery charger.

Thirdly - SPARX, not sure what you mean re winter? For clarification, I have no plans to use electrical heating in the garage.

Thanks for the advice guys - very much appreciated.
Purple
Rank: Labourer
Progress to next rank:
50%
Posts: 3
Joined: Wed Jul 18, 2007 6:27 pm

Postby sparx » Sat Jul 21, 2007 7:53 am

Sorry Purple but by tone of your question I assumed too much;
SWA= Steel Wire Armoured cable-it's proper title.
Pvc/Pvc = normal domestic type twin& earth cable also known as 6242Y.
[T]erra-[T]erra = method of earthing an installation (or part of) by use of an earth rod & not connecting to main earth, but must use RCD then,
I meant not to forget need warmth in winter & not electric.
B.W. SPARX
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