A normally closed (NC) contact is a type of electrical contact that, under normal conditions (without applied voltage or external action), is closed, allowing the flow of current. This means that when the contact is not activated (for example, not triggered by a switch or a relay), the circuit is complete and the current can flow. When the contact is activated (for example, with an excited relay), the normally closed contact opens, interrupting the current flow and thus opening the circuit. In practice, an NC contact is used in situations where a circuit should be active until a certain mechanism or condition is activated, causing the contact to open and interrupt the current flow. It is the opposite of a normally open (NO) contact, which is open when not activated and closes when triggered and it is the green Normally Open NO contact our code 73005T.