RE: Re: Consumer Units

["James Hoye" <james.hoye@xxxxxxx>]

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> I have an alley between my house and next door with the meters fitted
in
> this area, what I was planning was having the house consumer unit
fitted
> there then fit units for the AD10's at my node 0 in the top room (loft
> conversion) the distance between these points will be around 40 feet
so
> maybe too far as mentioned by Dr John.

The few feet limit is the distance between the LEB meter and your consumer
unit.  You can increase this distance, but the LEB will probably stipulate
that you have to use >25mm tails, and a larger earth conductor
(depending on
your earthing system).  This is because their cutout (80 or 100A typically)
is the only thing protecting the tails - and if a fault were to develop
between the cutout and consumer unit, there would be a fault current in
excess of probably 200A before their fuse went.  Under-rated tails would
get
very hot and would pose a significant fire risk.

In regards to your specific question about siting a CU in node zero for
housing your X10 DIN modules, there should be absolutely no problem with
this.  You just need to run a suitably rated cable from an MCB way on you
main CU up to the one(s) in node zero.  The only proviso is that you must
use suitable cable - this means if you are running from a 6A MCB then 1.5mm
will do, 16/20A use 2.5mm and for a 32A you will need 4mm.  The purpose of
the MCB is to _protect_ the cable by limiting the current in the event of
any fault.  One other point is that once you bring your cable up to the
node
zero CU, you _must_ use another suitably rated MCB (typically 6A for
lighting) before you wire in 1.5mm for your X10 and lighting circuits.

If you go _down_ in cable size, then you should use a fuse or MCB at the
'join' to protect the smaller cable.

If you are more interested, then I can recommend reading the IEE 16th
Edition Wiring Regulations On Site Guide as it gives a good overview of
domestic electrics.  There are also tables for derating cables depending on
their fixing method and what materials they pass through.  Remember, safe
not sorry.
http://www.amazon.co.uk/exec/obidos/ASIN/0852969295/qid=970658173/sr=1-1/026
-3724387-8058838

James H




____________________________________
Automated Home UK
http://www.automatedhome.co.uk
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