A few questions:
1) What are you doing for a GFCI?
2) What type of element do you have? A 240v element requires H-H-G, so 3 wires, not 4.
3) Do you need the neutral for your control panel to run a 120v circuit?
4) You will make sure that any power cord you have terminates with a female receptacle end, not a male plug which could be live, correct?