Good points by Derek.
In Europe, their services have just one hot leg which is 220V @ 50 hertz and a return. Their single phase is actually "single" phase (one hot). And so it is very important that everything has a dedicated neutral.
EMF is electro-motive force, or, voltage, right? You must be talking about eddy currents or very strong magnetic fields...
I also am not an engineer but the only thing I can think of is the same thing Derek mentioned last: One hot in a conduit with nothing to balance it out, or dangerous inbalances.
