I wanted to know if I could use a load center rated at 120/240V in a foreign
country where each leg of hot entering the load center is 220V.
If by "foreign" you mean Europe or the countries that follow the
European 220-230 V. 50 Hz standard, be aware that the systems are very
different as is the equipment that is designed for them.
The North American "Edison" system is typically 120/240 V. 60 Hz
single phase with a center tapped neutral at the secondary of the
service transformer. This transformer is typically pole or pad
mounted.
The advantages of this system are as follows:
1. Safety - No voltage over the nominal 120 V. to ground appears on
any conductor entering the house.
2. Versatility - Dual voltages 120/240 are available. 120 for
lighting and small appliance loads. 240 V. for the heaver appliances,
water heaters, dryers, range, air handler, etc.
3. Efficiency - The neutral carries only the difference current
between the two hot legs, thus giving less voltage drop (that of a 240
V. circuit) on the 120 volt circuits.
4. Economical (for the power company) - Only one hot primary and one
neutral are needed to serve distant house and remote farms. It is not
necessary to run 3 phase conductors as is the common practice in
Europe and other lands although in North America, 3-phase power is
readily available for farms and businesses that need it.
In England, for example, you have the "other" system where you have
one hot wire running at 230 Volts or so, one neutral, and one ground
wire. The panel boxes are designed differently to accommodate this
type of configuration with one large hot buss instead of two.
If a typical 120/240 USA cb panel were used on the European system,
for example, it would have to be fed by two (in phase hot wires). The
neutral buss would carry double the current (instead of just the
difference current) All the breakers would have to be rated for 240
and would have to be single pole- non ganged and operable safely on 50
Hz. Not sure that all these parts exist and if it would pass local
codes. I don't think so.
Beachcomber
