Date: Sun, 03 Apr 2011 10:51:58 -0700
From: Jim Brown <jim@audiosystemsgroup.com>
Subject: Re: [Amps] what is a 4 wire 240VAC service?
On 4/3/2011 7:57 AM, Charles Harpole wrote:
> Maybe being in Thailand, where 230vac is supplied with TWO wires, makes me
> ask.... what is 4-wire 240vac service?
## In Thailand,.... and the UK, etc,,..sure they give you 230 vac from the
street..BUT one of those
two wires is GRNDED at the pole. In essence, you have 1 hot and one
neutral/grnd coming in off
the street. So you are getting UB balanced 230 vac, Here in nA, we get 240
vac balanced power....and the sec
of the pole pig is the neutral..which is also bonde to grnd....and also bonded
to the return wire of the 14.4 kv.
## IE: the 14.4 kv pair of wires coming dowen the street.... the lower one is
grnded.
Charles,
There's a tutorial on Power and Grounding for Audio and Video Systems on
my website that explains most of what you want to know, and it covers
variations in practice over most of the world.
http://audiosystemsgroup.com/publish.htm
Inside buildings, an appliance like a clothes dryer that needs 240V
power, would get both sides of 240V plus the ground. IF that appliance
also needed 120V power, the neutral wire must also be connected, and the
120V load must be connected between one side of 120V and neutral.
### here's where they scrwed up with 30A dryer circuits imo. They shoulda
just used a 240 vac motor to turn the drum instead of a 120 vac motor. Then
the neutral
wouldn't be required. These days, dryers have several heat settings..and the
neutral is used.
Jim VE7RF
The same standards (and laws of physics) apply in your part of the
world, except that voltages are multiplied by two and currents are
divided by two for the same load.
73, Jim Brown K9YC
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