3 phase 415V vs 2 phase 208V
@ozzie908
You have to first understand several things.
First, you have to understand that alternating current is a sinewave. That means the voltage fluctuates from a positive peak voltage through 0V to a negative peak voltage to 0V back to the peak voltage, 50 or 60 times a SECOND respectivley.
The voltage given is the rms (root mean square, fancy engineering speak) voltage which is - loosely put - the voltage that averages out of that wave form.
So for 220V the peak voltage is somewhat higher (like 315V or something like that), for 110V in the US as well (that should be at 180V to 200V or such).
That dosen't matter to loads as the time spent at exactly 0V is indefinetly small and any capacity in a design can perfectly well buffer that out.
Second, these voltages are always relative to 0V.
You need a refference to which you measure the voltage, that's why a multimeter has 2 probes: You measure one point relative to another.
In your supply you technicly have 2 0V refferences: neutral and earth.
So (don't do this) if you would measure any phase to neutral or to earth the measurement should be 0.
TECHNICLY neutral and earth should be 0V to each other. That however is not really ever the case, so don't think you can just touch neutral and be fine.
Side note there: The reason we don't just use neutral as ground is that a fault to a true ground basicly always has an infinetly smaller resitance than the way to neutral.
Last, you have to understand that both the US and EU power grid are fare more simmilar then you imagine.
They have 5 wires max: 3 phases, all at the same voltage to neutral; neutral and earth.
Only difference is that that voltage is once 110V rms and once 220V rms.
Now the magic: These 3 phases are shifted to each other so that they alternate at reaching their peak voltage.
As said before, measuring voltages is done between 2 points as a refference to each other.
So, if don't measure to 0V neutral but to a different phase, you suddenly have a different voltage.
It still has the same frequency, but is shifted differently again and has a higher peak and thus a higher rms voltage.
Your circuit breaker dosen't care much as it just checks for total current and there is no fault to ground, so the RCD dosen't care.
Measuring power usage and makeing sure no one phase is ever overloaded is a little more complicated thus these systems are mainly regulated by the power company and used only when need.
Makes that more expensive as well.
Most equipment using all 5 connection in a house enviroment is usually not really grabhing the higher voltage but just refferencing each phase seperatley to neutral for 3 seperate circuits.
A lot of ovens or especially cooktops do that and split the usual 4 zones in 2 subdevisions with one large and one small burner plus the oven seperate.
In the US, they use it to get higher voltage.
It is also verry advantageous for running fixed speed motors as these 3 phase each single refferenced to neutral already produce a stable enough rotating magnetic field, perfect for example for industrial compressors.
On the option of an aditional rinse only:
Been using a short cold cycle of appropiate design as a stand in for a rinse only on many machines.
Over here that is often better and quicker then a true rinse only cycle.