[Boatanchors] Running European 230 VAC on our AC

[J. Forster]

In a properly functioning circuit, the sum of the current to and from the
load should be exactly equal. Any difference indicated a ground fault. A
GFCI or GFI senses the current different, and if it exceeds a preset trip
point, the breaker opens.


P              |x| <...  Core
A  ---blk----------------------- To
N  ---wht----------------------- Load
E            |-----|
L            | |x| |
             |     |
            Trip Circuit

The differencing is done with a small current transformer.

-John

==============



> On 10/19/2012 17:50, Albert LaFrance wrote:
>> A basic 240 volt circuit is two hots and a (safety) ground.  The hots
>> can be
>> any color except white (reserved for neutrals) and green (reserved for
>> ground).  Typically they will be black and red.
>>
>> A 120/240 volt circuit will have two hots, a neutral and a ground.  This
>> four-wire circuit is required whenever any part of the load requires
>> 120V;
>> for example a range which puts either 120 or 240 on a heating element
>> depending on the temperature setting.  This can be confusing because, in
>> the
>> past, the National Electrical Code allowed one conductor to serve as
>> both
>> neutral and safety ground in specific cases (ranges  being the one I
>> know
>> for sure), but  now that's prohibited.  The neutral is considered to be
>> (and
>> is!) a current-carrying conductor and must be separate from the ground,
>> which is provided for safety.  The neutral and ground are only
>> interconnected at the service panel.  I believe the reasoning is that,
>> if
>> the neutral carries current, it will have a voltage drop, and if the
>> neutral
>> were tied to an appliance cabinet, there would be a possibly hazardous
>> voltage difference between that appliance and a nearby grounded object.
> Albert,
>
> I love these types of exchanges.. as I always learn something new.
> Thanks for this clear description.
>
> Would you know how neutral is used in a GFCI?
>
> Seems like Neutral would be a good means of detecting protective ground
> issues.
>
> /m
>
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