The minimum gap distance between two electrodes is ideally zero, but practical applications require a safe distance to prevent sparking, which depends on the materials used and the potential difference. In this case, the electrodes are made of copper and silver rivets, and the user is working on a power relay with normally open (NO) and normally closed (NC) connections. The challenge lies in ensuring a safe distance for the NC connection to avoid sparking when the NO connection is open. The shape of the electrodes can influence the gap distance, with one rivet having a flat surface and the other a slight curve. For further understanding, referencing "Paschen Curves" is suggested for calculating the breakdown voltage in gases.
