Re: [CAD_CAM_EDM_DRO] Re: Re[1]: FYI: Home Depot Good buy on conns/cables 20'...

In a message dated 04-Oct-00 03:32:15 Central Daylight Time,
Ian@... writes:

<< does each house have its own transformer or is power
brought into the house on a four wire system? If the latter it must be
quite expensive to lay service cables compared with ours - a two-cored, lead
sheathed cable - the lead sheathing being connected to earth at the power
station and to other earth spikes at various points. Its also required on
new buildings now to fit a RCCD breaker at the fuseboard (the type that
monitors the current balance between 'live' (hot) and 'neutral' wires and
assumes that any imbalance represents a fault condition and so trips. >>

Ian: Before some licensed electrician answers this with a "professional"
answer, and has you totally confused, lemme tell ya how we Texans do it (our
"rules" for hanging/applying utility transformers "on the pole" are
very-often more modern than those used "up-East"!)

First, no, houses would have their "own" transformers only if they are
separated from others by more than, say, 100 meters or so. In "new"
subdivisions where the houses are all made of ticky-tacky and they all look
just the same, there is often a steel "box" on the earth in the back-yards,
"middle of the block", where the rear property-lines coincide, and that ONE
box will supply four houses. The high-voltage primary to these boxes is
somewhere in the range of 7 to 20 KV; I do NOT know exactly-what, but surely,
not just ONE standard! I once worked for a summer (as a po' student) for a
local electrical utility, and I irritated the "ol' boys on the truck" with
questions, and I learned that primaries were 4, 7, 14, 19.9 KV for
"distribution circuits" ("pole-to-pole", for residences and small
businesses). and anything higher than about 20 KV, up to 500 KV, was
"transmission voltage". A "drop" from the transformer "on the pole" or "in
the back garden" the the meter-panel on the house is usually three-wire; two
black PVC-insulated wires spiralled around a like-size bare
(nowadays-usually-) aluminum conductor.

What you are calling a "RCCD" breaker is here called a "ground-fault
breaker", I think. They are now "code" for such as outlets over bathroom or
kitchen basins, or outdoor outlets (where one would plug-in electric
appliances outdoors). Often, these outdoor outlets are simply "paralleled"
to the GF outlets in the nearest loo. I think there are now GF breakers for
these loads, but I haven't seen any, yet. What WE have is a "funny" outlet
in the loo with two buttons on it, one to "test" and one to "reset". They
would activate if a couple mA of the current flowing in the "hot" did not
flow BACK in that neutral (i.e., through a basin full of water, or a persons
chubby fingers, etc.).

I will leave it for some professional electrician to tell you all about the
NEC and their bureacracy, and how that is NOT a government organization, and
has NO "authority" at all! I am an "alternate" on a "low-voltage panel" of
the NEC, and have been to only ONE meeting years ago, when the "regular"
couldn't attend, and I TELL ya! Those panels for "lighting voltage" must be
sumpin! Thank all Goodness I am not on one of those! I'd quit after 15
minutes of that [deleted]!

Jan Rowland, Yank Troll