David Hansen wrote:
On 3 Sep 2006 10:59:11 -0700 someone who may be
wrote this:-
what i am uncertain of is i need to switch one light in the kitchen
from two locations and another light from just one.
//snip//
I'm no lemon ( electronic
engineering) but havent done any domestic installations before.
It would seem you need to reorient yourself. There's a major change of
emphasis in electrical theory when you switch to domestic 240V house
wiring from electronics. In domestic cabling the cables may carry
heavy currents & thus get warm & drop appreciable voltage over the run.
Circuit calcs & routes have to allow for this so the cable does not
get overhot (normal limt 70degC) & keep voltage drop to 4%. Likewise
there's concern about fault conditions and protection and circuits have
to cut out within designated limits of time and/or current.
Unlike electronics domestic electrics doesn't usually concern itself
with the characteristics of what is plugged into a circuit (beyond the
current drawn) nor about inductances or capacitance - only resistive
circuit elements are considered. The main focuses are on the contents
of the Consumer Unit and the sizing and route of cables, unlike
electronics where the major emphasis is on the characteristics of
components.
Suggest you look in your library for books by Whitfield and Scaddan: in
the end it is likely you will want the IEE On-Site Guide.
You would also do well to google this group for all manner of domestic
electrical threads, there's a goldmine of information there.
So far as B Regs & Part P go, specify in the plans submitted or B regs
notice the elec work is involved then you are covered for whatever work
you do yourself wherever it is.
Good luck.