"Mr Fizzion" wrote in message
...
On Thu, 25 Aug 2005 10:13:08 +0100, Cordless Crazy
wrote:

3. What size of cable would be required on this 55m run with, what I
assume will be, a huge voltage drop?

Voltage drop is given by V=IR where I is the current in amps and R is
the resistance of the wires in ohms. The resistance of the wires is
found from the resistivity of copper - 1.68*10^-8 ohm metres: R =
(length in metres * resitivity) / cross-sectional area of the wire in
square metres.

You can use the voltage drop calculator here to find the size of wire you
need.
http://www.tlc-direct.co.uk/Technica...ltageDrop.html

My Dad ran 6mm for 50m to his garden shed to power lights and power tools.
Wire got there in a combination of tacked onto wall and burried underground.
Came from a small CU (holding 63A RCD and 2 MCB's, on for garage) next to
main CU (wired up using 10mm wires) so that you could isolate the supply
easily and if there was a fault would not affect any of the house ring
mains. Ran to another CU in shed with 63A switch and split into plugs and
lighting via two MCB's. Not too sure what was done with earth but I think an
earth rod was used.