Originally Posted by mpoulton
Have to be very careful with this. It's a great solution if the load is lighting only and always constant. But if there is any variation in the load this will result in unacceptably high voltage when the load is minimal.
Yes, you have to get a xformer with good regulation such that at zero load you're maybe +10% above nominal value and at 20A you're at -10%.
PoCo's xformer is right outside my house so a 20A load drops the 240V by 0.4V measured at the panel so that's probably the best regulation you can reasonably expect.
CFLs or LED lighting may not be nearly as sensitive to overvoltage as incands.