Hi there
we've just got a new concrete garage built - 40sqm, situated about
10m from the house and around 15m from our consumer unit.

I would like to run mains to this garage, to supply lighting and light
power. I only intend this to be for 'domestic DIY' power, no plant
machinery or anything like that.

I'm competent in actually doing the wiring but a little rusty on
modern practice. My plan #1 is to run a new circuit of 4mm 3core
armoured cable to the garage, then fit a 2-way consumer unit and run
lighting and power off that.

Quick question - is this feasible/sensible? & if not, can anyone
suggest a better alternative?

Thanks for any suggestions
Jon N

On 13 Oct 2003 11:18:59 -0700, (Jon Nicoll) wrote:

Hi there
we've just got a new concrete garage built - 40sqm, situated about
10m from the house and around 15m from our consumer unit.

I would like to run mains to this garage, to supply lighting and light
power. I only intend this to be for 'domestic DIY' power, no plant
machinery or anything like that.

I'm competent in actually doing the wiring but a little rusty on
modern practice. My plan #1 is to run a new circuit of 4mm 3core
armoured cable to the garage, then fit a 2-way consumer unit and run
lighting and power off that.

Quick question - is this feasible/sensible? & if not, can anyone
suggest a better alternative?

Thanks for any suggestions
Jon N

Sounds reasonable - It would be a good idea to fit an RCD on the garage socket supply (not the
lights - you don't want them going out when you jigsaw through the cable..!).
Garage supply should have its own MCB in the main house CU

"Mike Harrison" wrote in message
...
On 13 Oct 2003 11:18:59 -0700, (Jon Nicoll) wrote:

Hi there
we've just got a new concrete garage built - 40sqm, situated about
10m from the house and around 15m from our consumer unit.

I would like to run mains to this garage, to supply lighting and light
power. I only intend this to be for 'domestic DIY' power, no plant
machinery or anything like that.

I'm competent in actually doing the wiring but a little rusty on
modern practice. My plan #1 is to run a new circuit of 4mm 3core
armoured cable to the garage, then fit a 2-way consumer unit and run
lighting and power off that.

Quick question - is this feasible/sensible? & if not, can anyone
suggest a better alternative?

Thanks for any suggestions
Jon N

Sounds reasonable - It would be a good idea to fit an RCD on the garage
socket supply (not the
lights - you don't want them going out when you jigsaw through the
cable..!).
Garage supply should have its own MCB in the main house CU

If you can make it sub-main supply from the house with its own switch gear,
then you'll stop any nuisance tripping of the circuits in the house.

It is easily done with use of Henley blocks (16mm Terminal block) to split
the tails from your meter to another single way consumer unit dedicated to
the garage supply.

I would also advise you, if using an RCD, to make a separate earth point
from the consumer unit in the garage and on to a ground spike at the garage
end of the new supply.


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Mike Harrison wrote:
On 13 Oct 2003 11:18:59 -0700, (Jon Nicoll) wrote:

Hi there
we've just got a new concrete garage built - 40sqm, situated about
10m from the house and around 15m from our consumer unit.

I would like to run mains to this garage, to supply lighting and
light
power. I only intend this to be for 'domestic DIY' power, no plant
machinery or anything like that.

I'm competent in actually doing the wiring but a little rusty on
modern practice. My plan #1 is to run a new circuit of 4mm 3core
armoured cable to the garage, then fit a 2-way consumer unit and run
lighting and power off that.

Quick question - is this feasible/sensible? & if not, can anyone
suggest a better alternative?

Thanks for any suggestions
Jon N

Sounds reasonable - It would be a good idea to fit an RCD on the
garage socket supply (not the lights - you don't want them going out
when you jigsaw through the cable..!).
Garage supply should have its own MCB in the main house CU

I did this and used one of those garage consumer units as sold by the likes
of Screwfix.
Now you mention it the lights are fed from the RCD as well as the power....

I would like to run mains to this garage, to supply lighting and light
power. I only intend this to be for 'domestic DIY' power, no plant
machinery or anything like that.

A quick check shows that 4mm should be fine for a 32A radial with cable
length of 20m. This should be run off a separate MCB at the consumer unit.
Probably best on the non-RCD side.

You need to decide on earthing arrangements. A TT might be suggested in
these circumstances as it is really a separate building far from the house.
This requires you to isolate the earth on the cable at the garage end. Then
use a whole garage RCD and an earth rod.

Best is a 100mA Type S for the entire supply and a further 30mA immediate on
the socket circuits. However, you might not bother and just use a 30mA
immediate for the entire lot. Obviously, this cheaper option would mean you
lose lighting when the power trips.

Christian.

Hi Gents
Thanks for all your suggestions - very useful. I meant to suggest
an RCD, and was wondering about using a separate earth, so your
replies are spot on for me.

Thanks again
Jon N

My understanding of the regs is that you must have a separate earth
arrangement for the garage and not connect the earth through the supply
cable from the house.Screwfix do a small garage consumer unit (c£29) and
earth rod.Try and estimate what current you will draw from garage sockets to
ensure you get correct cable size and no more than 4% voltage drop when
fully loaded.
Mark
"Jon Nicoll" wrote in message
om...
Hi Gents
Thanks for all your suggestions - very useful. I meant to suggest
an RCD, and was wondering about using a separate earth, so your
replies are spot on for me.

Thanks again
Jon N