SPDT mechanical relay: do NO and NC pins short between each other as pole switches
Your part indicates from the characteristics table on Digikey that it is a DPDT Form C switch, meaning that it is a &quot;break before make&quot; kind of switch, and that behavior should be guaranteed as that is intentional. So, the switch is disengaged from one terminal before contacting the next: there should not ever be a connection. Form D is the &quot;make before break&quot; kind, where a connection between both terminals does occur. Here is a link talking a little more about relays and the different forms: Instructables.com