On Mar 16, 7:46*pm, andrew wrote:
NT wrote:
On Mar 16, 5:46 pm, Dave Osborne wrote:
On 16/03/2010 15:59, NT wrote:

On Mar 16, 10:50 am, Dave *wrote:
On 10/03/2010 21:15, andrew wrote:

Thanks for the input you two it's all interesting and pertinent.

AJH

Here on the other side of the Atlantic I have to agree with a previous
poster to this thread who wrote ..............

"Many "electricians" are sadly far from fully competent or hide
behind
the "safety" mantra when in reality there is no risk once the work is
completed, tested and covers/enclosures replaced."

Often found during a 40 year career in telecommunications, which often
involved power at many voltages and frequencies, that many
electricians knew much about 'wiring methods', how many inches of
slack, what gauge of wires and how many would fit through something
(e.g. conduit) etc. and by 'Rule of thumb' what size of wire or
circuit breaker to use etc. Many/most? had little idea of electrical
theory, or basic AC/DC principles. They definitely knew more than I
did when it came to 'Wiring something'!

But; having been trained in electrical theory, at many frequencies,
from audio to microwaves and how to repair and maintain electronic
equipment we were a little astounded that there was so little
knowledge of 3 phase, or even two phase and the relationships of
voltages. And mention mention 400 hertz AC or DC at say 500 amps, or
some old time wood/paper pulp mill 25 cycle motors or equipment some
of them and it didn't have any impact!

Now many years later my son who is fully trained Instrumentation
Technician (Off shore oil/gas with megawatts of power and very high
pressures) who has also done some teaching, is finding the same. Many
electricians 'may' know rudimentary volts and amps but not much
theory! Something missing in the training/technology courses?

Cos we don't see that deficiency here where there are some pretty
knowledgeable and practical people ready to advise.

Agree don't see why those three heating elements (control switching
aside) can't be paralleled and run at the reduced power. While may
need appreciation of whether the unit comes factory wired for 415 volt
delta or wye/star, should be do-able safely?

I do recall rigging up some sort of European/UK sourced small potters-
craft-maker's kiln (single phase but requiring rewiring for our two
hot 120 volt with 240 between them, as used for out hot water heaters
and cooking stoves) in some way years ago and apparently it worked for
years, safely, with no problems.