Is it legal to have a 4 wire machine connect to a 3 wire service. The machine is 240 V for all components in it except a 120v heater. L1 goes to one side of the heater and a neutral is connected to the other. The is a ground to the heater housing also. The neutral is bonded at the entrance to the machine to ground. Only 3 wires leave the machine. L1 L2 and Ground.