[Boatanchors] Running European 230 VAC on our AC

[Sheldon Daitch]

As noted, some 240VAC US appliances do need the neutral
to pick up the 120VAC for some 120VAC applications in the
unit.

We have a US built stove which the manufacturer has to add a
stepdown transformer for the export model, since the 230VAC
systems outside the US typically do not have the neutral
centertap.

In our stove, that stepdown transformer was an autotransfomer,
not an isolation transformer and it failed.  I discovered that the
way the transformer was wired and the stove was wired into
our 230VAC system that the common of the autotransformer
was wired to the high leg of the wiring and perhaps that was
the cause of the eventual failure of the transformer.

I bring this up, as running  230VAC equipment which is designed
for a hot and neutral might have some problems if the neutral
leg is actually 120VAC above ground.  In theory, no, but with
polarized systems, the powered unit is normally going to see
near-ground voltage outside the US, but in the US, the neutral
leg would be 120VAC above ground.

(One interesting aspect of many 230VAC systems outside the
US is that many residential systems are three phase, and
with 230VAC phase to neutral, phase to phase voltages are
in the 400VAC range.)

73
Sheldon


On 10/20/2012 4:08 PM, Ken wrote:
> Thanks Glen;
>         All my 240 at work and at home has 2 hots and a bare copper
> equipment ground run back to the panel.  No neutral is run to the
> equipment.
>
> Ken
>
>
> On 10/19/2012 06:18 PM, Glen Zook wrote:
>> Actually, the center is neutral which is connected at the power
>> entrance to ground.
>>
>> Where 3-wire 240 VAC wiring is in place, there is 120 VAC on either
>> side of neutral, which is "almost" at ground potential since the
>> neutral is bonded to the service ground rod at the breaker box.
>>
>> "Modern" requirements are for a 4-wire service in which a separate
>> ground wire is run.  This is the same ground as with 3-wire 120 VAC
>> service.
>>
>> The neutral can NEVER be considered to be "ground" even though the
>> neutral is required to be connected at "ground" at the entrance point.
>>   Due to IR drop, which, of course, depends on the current being drawn
>> through the neutral wire, there will be a voltage above actual ground
>> in the neutral.  At low current, not much.  But, as the current
>> increases so does this voltage difference between the neutral and the
>> actual ground.
>> Glen, K9STH
>>
>> Website: http://k9sth.com
>> ------------------------------------------------------------------------
>> *From:* Ken <ken at wa0sbu.com>
>> *To:* boatanchors at mailman.qth.net
>> *Sent:* Friday, October 19, 2012 4:15 PM
>> *Subject:* Re: [Boatanchors] Running European 230 VAC on our AC
>>
>> None of my 240 is wired that way.  120 on Hot 1, 120 on Hot 2.  And a
>> ground.  240Volt has 2 Hot wires.
>> Hot wires can be Black-Red or Black-White
>> Neutral not required for 240V.
>>
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