30 AMP OPS

[John Suter]

Hi Gregory,

It is not a good idea to try to mix and match dual
power sources, as in the following:

> I wonder if there is a way to hook into 110 30 amp
> and use the
> inverter to make the other leg for the cooktop?

These type connections (especially in motorhome type
applications where the grounding is minimal at best
and degrades with age) are prone to back-feeding where
a source of power can pass through an appliance
(without activating it, which would visually notify
the user) and continue on to another location where
someone might come in contact and become injured.

Simply said, don't mix and match sources unless you
are an accomplished electrician, and then label
everything so workman will also know what has been
done.

Not to belabor the point, but to provide an example
of the "lack of visual clues" some Forum folks may not
be aware of.

Typically, the 110V light over the table uses a
"dimmer" switch. In the "maximum dim" position, the
light will not illuminate. Yet, should one come in
contact with the hot wire of the light fixture, a
nasty/possibly fatal surprise awaits. 110V is
present. The dimmer has simply temporarily reduced
the amperage below the amount required for
illumination, but the 110 volt "electrical potential"
is fully available, just like a duplex (plug-in) wall
socket.

John Suter


--- Gregory OConnor wrote:

> Pete, "With your 30 amp 220 breaker at the house you
> have 30 amp
> available on each leg (red , Black) but not at the
> same time. " you
> can draw 30 amps through that breaker total. ie; '30
> on one leg and
> zero on the other' or '15 and 15'. or run a total
> of 30 X 110 =
> 3,300 watts. By design the breaker will trip if you
> draw more than
> 30 amps in any combination. You could simply
> replace the breaker
> with a 50 amp if you have proper rated wire leading
> up to the bus.
> Nothing wrong with leaving it 30 and managing the
> watt/ amp usage in
> the bus.
>
> I wonder if there is a way to hook into 110 30 amp
> and use the
> inverter to make the other leg for the cooktop?
>
>
> If you hook into 110 30A and turn on the cooktop, I
> wonder if the
> electricity will pass to appliances on the other
> leg? I have seen
> this happen, the cooktop rehostat became a light
> dimmer for lights on
> the dead leg.
>
> My electrical certification is limited to a merit
> badge and education
> I credited to a 'how to do it book'. Titled "Don't
> be shocked by the
> shorts"
>
> Gregory O'Connor
> 94ptRomolandCa
> Eagle'74
> --- In WanderlodgeForum@yahoogroups.com, Pete
> Masterson
> wrote:
> >
> > Gregory,
> >
> > I followed your explanation except for the part
> quoted below. The
> 30
> > amp 220 circuit in my home that I "stole" for the
> coach originally
> > served an electric stove (or oven, I forget which
> -- we converted
> the
> > house stove to natural gas). So what I don't
> understand is why the
> 30
> > amps available would be only on one leg or the
> other but not both?
> > The circuit is served by two breakers (switches
> tied together with
> a
> > metal bar) and wired with a red, black, white and
> green wire.
> White
> > is neutral, green is ground, I thought the black
> and red were each
> a
> > 30 amp "leg" of the circuit -- or am I missing
> something. (I'm not
> an
> > electrician, so "three phase" wiring isn't my area
> of clear
>
>
>
>
>


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