[Amps] what is a 4 wire 240VAC service?

[Jim Thomson]

Date: Sun, 3 Apr 2011 17:27:37 -0700 (PDT)
From: Roger Parsons <ve3zi at yahoo.com>
Subject: Re: [Amps] what is a 4 wire 240VAC service?


There are a couple of things I don't understand: :-)

(1) When it became clear, probably close to 100 years ago, that 120V was too low a voltage to efficiently power room (or tubes with handles) heaters and similar equipment, why did North America not follow the rest of the world and move to a 230V system? That is, a 3 wire 230V AC service.

&&&  The 230 vac Un-balanced service you see in the UK and else where is actually just a 2 x wire service.   Think of it as 230 hot...and a  grnded neutral.    It`s sorta  like a 120 vac circuit on steroids. 
&& They didn`t do themselves  any favours  with the 50 hz nonsense either.   60 divide by 50 = 1.2    All their pole pigs, etc,  have to be 20%  bigger .   Ever seen  blower specs  for both 50 +60 hz operation.  Run on 50 hz,
the rpm drops like a rock. and performance sufffers.    Any 60 hz plate xfmr, when  run on 50 hz... runs HOT.   50 hz stuff requires way more wire on the windings, inclusing xfmr`s and stuff like motor windings.

&&& If 50 hz sorta works..and 60 hz is better, they really should have use  a lot higher freq than 60 hz to start with.   You set a standard, then build a  national power grid, it`s  too late to change to plan B. 

&&  I read 2 x yrs ago, there is a new standard in the Pro audio industry..called ... `balanced power`     They ended up  with 60 vac  from each hot side to neutral.   It was recognized by the power co`s too..and has it`s own sub section
in the electrical code.   You can get the same result by running the same audio gear on 240 vac to begin with....if it`s capable of 240 vac operation.  




(2) What bright spark decided that black was a good colour choice for the hot wire?

&&&  who knows, the standards committee is my guess.  Telco`s  use BLACK  for everything.  Each end is well labeled of course. 

Actually, there are many other things I don't understand, but those will do for now.

&&&  here`s  what I don`t understand.   The enviro geeks are all hot  for these silly  all  electric cars....like the new nissan  `leaf`.   Each battery is $18K..and will only be at 80% capacity....after 5 yrs.   They have a range of 100 miles....which of course  drops to just 60 miles  during the summer..with Air conditioning on.  And down to just 40 miles in winter, with heat on.   They haven`t even factored other stuff in..like headlights at night, daytime running lights, stereo gear, power window`s, moon roof,s  power seats, heated seats, rear window electric defoggers, windshield wipers, etc, etc.  They take 22 hrs to charge up..with a 120 vac outlet.....and  7 hrs to charge with a 40 A  240 vac circuit.  the switching supply that puts out 480 vdc is another $2k. ..and of course requires the 240 vac  at 40A circuit.     With 9 x homes to a single 50 kva  xfmr  here in VE7-land...and all  with `200 Amp`   service...even a few of these cars plugged in  will surely sned our now overloaded grid into melt down.   can u imagine 2-3 of these things plugged in at your neighbours, next door.    Do the Grade 6 maths..... it ain`t gonna work.   

&& Now  Tesla motor`s claims their roadster is good for a whopping 350 km  on a single charge...and only requires to be plugged into any 120 vac outlet  for just 2-3 hrs....which of course is pure BS.   They claim they can get 300 Hp  and as much torque..from an AC motor..that`s smaller than a 5 x gal paint can.      $43 K  for a chevy volt...I don`t think so. 

end of rant............ Jim  VE7RF 

73 Roger
VE3ZI