1, how to calculate the distance between the power line and the ground, this look at the national standard is the corresponding width of the provisions. Like I engaged in medical equipment, my standards from the "GB 9706.1-2007 Medical Electrical Equipment Part 1: General Requirements for Safety" in the "creepage distance and electrical clearance" aspect of the above requirements.
2, and then you said that the terminal voltage problems, you can consider direct welding treatment;
3, the overall feeling of your voltage resistance can not be, one does not accurately know the value of the voltage resistance and clearance on the connection, and secondly, you said that the problem of the terminals.