I am considering installing a cylinder and boiler in a garage. I may
use two 3 kilowatt immersions. I need to take some cable from the
Consumer Unit to the garage underground. Supplying the boiler,
immersion, lights and sockets in there is more than what a direct
burial 2.5mm cable can provide. Doubling up two of these cables is cost
effective as heavy direct burial cable is expensive. Is it within regs
to have these cables on one 42A mcb at the CU and take it to a garage
CU in the garage and then take all the circuits off the Garage CU?
Makes sense to me.

Or is it best to have each cable on an mcb at the CU and no garage CU
with just two isolators as the cable enters the garage?

Any views?

TIA

wrote:

Doubling up two of these cables

If you mean using conductors in parallel on the same circuit, that is
generally frowned on.

heavy direct burial cable is expensive.

1.5mm 2 core SWA £0.88/m
2.5mm 2 core SWA £0.91/m
4.0mm 2 core SWA £1.20/m
6.0mm 2 core SWA £1.60/m

From http://www.tlc-direct.co.uk/Main_Ind...SWA/index.html
seems proportionately cheaper to me

Or is it best to have each cable on an mcb at the CU and no garage CU
with just two isolators as the cable enters the garage?

If you really want to use multiple cables then that would appear to be a
better way of doing it.

Andy Burns wrote:
wrote:

Doubling up two of these cables

If you mean using conductors in parallel on the same circuit, that is
generally frowned on.

heavy direct burial cable is expensive.

1.5mm 2 core SWA £0.88/m
2.5mm 2 core SWA £0.91/m
4.0mm 2 core SWA £1.20/m
6.0mm 2 core SWA £1.60/m

From http://www.tlc-direct.co.uk/Main_Ind...SWA/index.html
seems proportionately cheaper to me

Or is it best to have each cable on an mcb at the CU and no garage CU
with just two isolators as the cable enters the garage?

If you really want to use multiple cables then that would appear to be a
better way of doing it.

Thanks Andy. The 6mm 3 core will be difficult to bend. I intend to take
the cable up from the ground and through the wall. Dark coloured
plastic conduit will make it neater rising and going through the wall.
Do you have any recommendations on the conduit to use?

TIA.

On 28 Dec 2006 08:42:43 -0800, wrote:


Thanks Andy. The 6mm 3 core will be difficult to bend. I intend to take
the cable up from the ground and through the wall. Dark coloured
plastic conduit will make it neater rising and going through the wall.
Do you have any recommendations on the conduit to use?

TIA.

Just drill upward at about 60 degrees, below where you want to mount the CU.
Then cold chisel out the inside bends

Andy

Andy Burns wrote:
wrote:

Doubling up two of these cables


If you mean using conductors in parallel on the same circuit, that is
generally frowned on.

But is this any different from a ring main in essence?

heavy direct burial cable is expensive.


1.5mm 2 core SWA £0.88/m
2.5mm 2 core SWA £0.91/m
4.0mm 2 core SWA £1.20/m
6.0mm 2 core SWA £1.60/m

From http://www.tlc-direct.co.uk/Main_Ind...SWA/index.html
seems proportionately cheaper to me

Or is it best to have each cable on an mcb at the CU and no garage CU
with just two isolators as the cable enters the garage?


If you really want to use multiple cables then that would appear to be a
better way of doing it.

Agreed.

Steve.

In an earlier contribution to this discussion,
wrote:

I am considering installing a cylinder and boiler in a garage. I may
use two 3 kilowatt immersions. I need to take some cable from the
Consumer Unit to the garage underground. Supplying the boiler,
immersion, lights and sockets in there is more than what a direct
burial 2.5mm cable can provide. Doubling up two of these cables is
cost effective as heavy direct burial cable is expensive. Is it
within regs to have these cables on one 42A mcb at the CU and take it
to a garage CU in the garage and then take all the circuits off the
Garage CU? Makes sense to me.

Or is it best to have each cable on an mcb at the CU and no garage CU
with just two isolators as the cable enters the garage?

Any views?

TIA

Surely, one 6mm SWA cable would be best - and probably cheaper than 2 x
2.5mm cables. The problem with doubling is that if a poor contact develops
where they are connected to the CUs, one cable can end up taking all the
current - and will then overheat.
--
Cheers,
Roger
______
Email address maintained for newsgroup use only, and not regularly
monitored.. Messages sent to it may not be read for several weeks.
PLEASE REPLY TO NEWSGROUP!

In article m,
wrote:
Doubling up two of these cables is cost
effective as heavy direct burial cable is expensive.

Good grief.

At TLC prices 2.5mm TW&E is 0.97 gbp a metre. Assuming you want twice the
current carrying capacity, 6mm SWA is 1.60 a metre. And TW&E will require
additional protection.

Seems to me you've been listening to 'two combis' dribble too much.

--
*If you remember the '60s, you weren't really there

Dave Plowman London SW
To e-mail, change noise into sound.

"Dave Plowman (News)" wrote in message
...
In article m,
wrote:
Doubling up two of these cables is cost
effective as heavy direct burial cable is expensive.

Good grief.

At TLC prices 2.5mm TW&E is 0.97 gbp a metre. Assuming you want twice the
current carrying capacity, 6mm SWA is 1.60 a metre. And TW&E will require
additional protection.

Seems to me you've been listening to 'two combis' dribble too much.

I was wondering how the heating pipes were going to be laid between the
house and the garage, if the boiler is going to be used to heat the house.

Adam

ARWadsworth wrote:
"Dave Plowman (News)" wrote in message
...
In article m,
wrote:
Doubling up two of these cables is cost
effective as heavy direct burial cable is expensive.

Good grief.

At TLC prices 2.5mm TW&E is 0.97 gbp a metre. Assuming you want twice the
current carrying capacity, 6mm SWA is 1.60 a metre. And TW&E will require
additional protection.

Seems to me you've been listening to 'two combis' dribble too much.

I was wondering how the heating pipes were going to be laid between the
house and the garage, if the boiler is going to be used to heat the house.

Adam

Thanks to all. I will use one 6mm cable and a garage CU. I assume this
can enter via an angled hole through the footings rather than up from
the ground and through the wall. Is that so?

I am thinking of taking the water pipes underground through a 110mm
plastic pipe, with the water pipes being plastic, fully insulated and
500 mm deep. It will be simple enough to do, apart from some digging,
and save a lot of space in the house. It looks to be well worth it for
the space gains.

Thanks and happy new year to everyone on uk.d-i-y.

On 2007-01-01 18:13:24 +0000, said:


ARWadsworth wrote:
"Dave Plowman (News)" wrote in message
...
In article m,
wrote:
Doubling up two of these cables is cost
effective as heavy direct burial cable is expensive.

Good grief.

At TLC prices 2.5mm TW&E is 0.97 gbp a metre. Assuming you want twice the
current carrying capacity, 6mm SWA is 1.60 a metre. And TW&E will require
additional protection.

Seems to me you've been listening to 'two combis' dribble too much.

I was wondering how the heating pipes were going to be laid between the
house and the garage, if the boiler is going to be used to heat the house.

Adam

Thanks to all. I will use one 6mm cable and a garage CU. I assume this
can enter via an angled hole through the footings rather than up from
the ground and through the wall. Is that so?

I am thinking of taking the water pipes underground through a 110mm
plastic pipe, with the water pipes being plastic, fully insulated and
500 mm deep. It will be simple enough to do, apart from some digging,
and save a lot of space in the house. It looks to be well worth it for
the space gains.

Thanks and happy new year to everyone on uk.d-i-y.

A few tips here (because I've done it)....

- 110mm pipe will not be large enough to fit two 22mm pipes with a
respectable amount
of insulation. The recommended amount of insulation is at least the
diameter of the pipes
so this comes to 66mm all up for each one. Standard insulation
thicknesses appear to be 9, 13, 19
and 25mm. You would have to go down to 9mm, which is not enough.
I used 160mm and there was then plenty of room.

- I used plastic barrier pipe in coil form and threaded it through so
that there were no joints in the underground
section. There needed to be one pipe elbow at one end and two at the
other. To assemble everything, it proved easiest to insulate and tape
each pipe and then to tape the two together at regular intervals to
make a bundle.
This was easy to thread through the underground soil pipe. The elbows
were put on afterwards with the pipe having been warmed wih hot water
first. It's much easier this way than trying to thread the individual
pipes through or to push or pull the bundle though.

"Andy Hall" wrote in message
...
On 2007-01-01 18:13:24 +0000, said:


ARWadsworth wrote:
"Dave Plowman (News)" wrote in message
...
In article m,
wrote:
Doubling up two of these cables is cost
effective as heavy direct burial cable is expensive.

Good grief.

At TLC prices 2.5mm TW&E is 0.97 gbp a metre. Assuming you want twice
the
current carrying capacity, 6mm SWA is 1.60 a metre. And TW&E will
require
additional protection.

Seems to me you've been listening to 'two combis' dribble too much.

I was wondering how the heating pipes were going to be laid between the
house and the garage, if the boiler is going to be used to heat the
house.

Adam

Thanks to all. I will use one 6mm cable and a garage CU. I assume this
can enter via an angled hole through the footings rather than up from
the ground and through the wall. Is that so?

I am thinking of taking the water pipes underground through a 110mm
plastic pipe, with the water pipes being plastic, fully insulated and
500 mm deep. It will be simple enough to do, apart from some digging,
and save a lot of space in the house. It looks to be well worth it for
the space gains.

Thanks and happy new year to everyone on uk.d-i-y.

A few tips here (because I've done it)....

- 110mm pipe will not be large enough to fit two 22mm pipes with a
respectable amount
of insulation. The recommended amount of insulation is at least the
diameter of the pipes
so this comes to 66mm all up for each one. Standard insulation
thicknesses appear to be 9, 13, 19
and 25mm. You would have to go down to 9mm, which is not enough.
I used 160mm and there was then plenty of room.

- I used plastic barrier pipe in coil form and threaded it through so that
there were no joints in the underground
section. There needed to be one pipe elbow at one end and two at the
other. To assemble everything, it proved easiest to insulate and tape
each pipe and then to tape the two together at regular intervals to make a
bundle.
This was easy to thread through the underground soil pipe. The elbows
were put on afterwards with the pipe having been warmed wih hot water
first. It's much easier this way than trying to thread the individual
pipes through or to push or pull the bundle though.

Matt, you have been on the new years pop. You said you taped the pipes
together and pushed it through. Is that so? You can get larger plastic
undergound pipes than 110mm. Put on the thickest lagging you can and fill
the large conduit pipe with vermiculite. It would be beneficial to cover
the underground conduit pipe with underground Jablite foam to prevent heat
loss to the colder earth on the top of the pipe.

Another minor point. If the mains water pipe enters a detached garage,
then underground to the main house will it need a stop cock entering
the house as well as the garage?

wrote in message
ups.com...
Another minor point. If the mains water pipe enters a detached garage,
then underground to the main house will it need a stop cock entering
the house as well as the garage?

Yes.

On Tue, 2 Jan 2007 00:53:58 -0000, Doctor Drivel wrote:

wrote in message
ups.com...
Another minor point. If the mains water pipe enters a detached garage,
then underground to the main house will it need a stop cock entering
the house as well as the garage?

Yes.

Talking to yourself Drivel? It's a sign of madness. As to be honest are
each of your posts to Usenet.

wrote:

Another minor point. If the mains water pipe enters a detached garage,
then underground to the main house will it need a stop cock entering
the house as well as the garage?

Can you not reply in thread instaed of posting a new one.

Dave

"Dave Plowman (News)" wrote in message
...
In article m,
wrote:
Doubling up two of these cables is cost
effective as heavy direct burial cable is expensive.

Good

You need to eff off. This is for your own good.

In article ews.net,
Doctor Drivel wrote:

"Dave Plowman (News)" wrote in message
...
In article m,
wrote:
Doubling up two of these cables is cost
effective as heavy direct burial cable is expensive.

Good

You need to eff off. This is for your own good.

You need to seek treatment if your only contribution to a thread is this.
We all know you had some form of breakdown when you threatened to 'set'
the police on me. Perhaps it's time to go back to the doctor.

--
*Of course I'm against sin; I'm against anything that I'm too old to enjoy.

Dave Plowman London SW
To e-mail, change noise into sound.

"Dave Plowman (News)" wrote in message
...
In article ews.net,
Doctor Drivel wrote:

"Dave Plowman (News)" wrote in message
...
In article m,
wrote:
Doubling up two of these cables is cost
effective as heavy direct burial cable is expensive.

Good

You need to eff off. This is for your own good.

You

You really do need to eff off. It will do you the world of good.

Doctor Drivel wrote:
"Dave Plowman (News)" wrote in message
...
In article ews.net,
Doctor Drivel wrote:

"Dave Plowman (News)" wrote in message
...
In article m,
wrote:
Doubling up two of these cables is cost
effective as heavy direct burial cable is expensive.

Good

You need to eff off. This is for your own good.

You

You really do need to eff off. It will do you the world of good.

I agree. Dave Plowman should eff off as he is only of nusiance value.

wrote:
I am considering installing a cylinder and boiler in a garage. I may
use two 3 kilowatt immersions. I need to take some cable from the
Consumer Unit to the garage underground. Supplying the boiler,
immersion, lights and sockets in there is more than what a direct
burial 2.5mm cable can provide. Doubling up two of these cables is cost
effective as heavy direct burial cable is expensive. Is it within regs
to have these cables on one 42A mcb at the CU and take it to a garage
CU in the garage and then take all the circuits off the Garage CU?
Makes sense to me.

Or is it best to have each cable on an mcb at the CU and no garage CU
with just two isolators as the cable enters the garage?

Any views?

TIA

two 2.5mm cables in a ring main can be protected by a 32A MCB not 42 if
you really meant that. Or did you mean 45? IME you should use one 6mm
subject to volt drop considerations.
Why do you plan to use two immersion heaters especially if you have a
boiler? You need to investigate diversity I think.
Have you thought out your earth / protection system?

In article m,
writes:
I am considering installing a cylinder and boiler in a garage. I may
use two 3 kilowatt immersions. I need to take some cable from the
Consumer Unit to the garage underground. Supplying the boiler,
immersion, lights and sockets in there is more than what a direct
burial 2.5mm cable can provide. Doubling up two of these cables is cost
effective as heavy direct burial cable is expensive. Is it within regs
to have these cables on one 42A mcb at the CU and take it to a garage
CU in the garage and then take all the circuits off the Garage CU?

No.

Or is it best to have each cable on an mcb at the CU and no garage CU
with just two isolators as the cable enters the garage?

Any views?

You have to conform to the "conductors in parallel" part of
the regs. In this case, you could probably do it by using
a pair of ganged breakers at the CU (so if one trips, it
switches off the other too). For more than two cables, you
would normally need a set of ganged breakers at both ends
of the parallel run. However, you will have to sit down and
work out all possible fault scenarios, and that the protective
devices are effective. The harder ones to meet are a short in
the cable near the CU, where the fault current is being back-
fed via the other conductor.

Another factor is that you will have to derate the cables
if you lay two together (derating factor) as they'll heat
each other up.

As someone else already said, you really don't want to go
this route...

--
Andrew Gabriel