The main problem is that you are playing with a device that can kill you, that can output 2800 vac and over 1000 watts!
But if you know what you´re doing (?),.. the magnetising current should be near 500 mA (minimum current to the transformer). Suppose 0.1 ohm on primary (50 mV voltage loss) the output could be near 3.8 vac but total power output is only 0.2 volts times 10 amps (the designed current of primary coil) or only 2 watts!, anyway it´s much better to buy a little transformer