I have a DC circuit that runs 1 A current in it when it is closed. When I close the circuit, i notice that there is a spark between the terminals of connection when they're brought close enough, just before completing the connection. I understand that this is due to the electrical breakdown of air but the air is such an excellent insulator (breakdown voltage=3000V/mm).
- Is this sparking dependent on the closed circuit current (higher current, higher probability of sparking) or the potential difference between the terminals or some other factor?
- How would there be a difference in potential if it's just two broken ends of a circuit which are going to be joined together to make it live?
- If it is dependent on the closed circuit current, what is the threshold current to cause the sparking?