On 7/24/2014 9:38 PM, Lloyd E. Sponenburgh wrote:
John B. Slocomb fired this volley in
:

Are you somehow postulating that 110 VAC will kill you less dead that
440 VAC? Or to put it another way, that 440 VAC will kill you deader
than 110 VAC?

Or you just posturing?


Are you perhaps forgetting that the higher the voltage, the more
resistance it can have in the load path with the same current flow? Are
you also forgetting that insulation of a given thickness is more easily
breached by a higher voltage than a lower one?

So, say you're all decked out in slightly sweaty equipment, and your
total resistance including the gloves is 5Kohms. Now 110VAC only can
make 22ma flow through you. 240 can cause 48ma.

So, we better double our insulation to 10K including us. Now 240 can
only cause 24ma to flow. 440 can cause 44ma.

See the relationships?
(besides, unless you're out on the end of a really long rural run with
all sorts of subscribers along it, there's not much 110VAC around
anymore. 120-125 is the 'new' 110.

LLoyd

The problem here is you consider a constant power. Power transformers
can be considered 'infinite'. When the human body is concerned. You
don't need a monster Semi-Trailer size transformer at any voltage.

A transformer with a core of a softball is 100 watts or more. That is
when it starts to heat up. It can deliver more and more but the wire
insulation melts. Then the copper melts...

Around here it is 125 to 135. They try to keep it lower but line loss
and transformer loss grabs the 'extra' when the load goes up for
breakfast and the air conditioning switches on.

I've been in small areas and they use 'swinging transformers'. The are
like swinging chokes in that the current through the secondary drives
the slug in the transformer and it switches a tap to increase or
decrease the output voltage preventing a brown out or over voltage.

The transformers are normally make before break so each winding shorts
out when the switch moves and a shot of unwanted power is sent on the line.

Martin