View Single Post
  #17   Report Post  
Posted to uk.d-i-y
Andy Hall Andy Hall is offline
external usenet poster
 
Posts: 9,122
Default Doubling up underground cable.

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.