Re: ground fault detector
If I were you I wouldn't go into this subject, as you have to remember that there will be great liability from your side to ensure that if something goes wrong, you will be able to provide funds to cover the "to be" victum(s).
You will never be able to predict which component can, hypothetically, give up, but you will be fully responsible for the final product..
So, consider this thoroughly, and if you still want to proceede .. come back ..
Regards,
IanP