The Node Label component may be placed only upon an electrical wire. Its express purpose is to provide a unique name for a particular electrical node, which will be both displayed on the schematic, an used as a unique identifier in the project source code. Electrical nodes that are not associated with a node label (or named by a component) are given a generic name when the project source code is constructed (ex. NT_1, NT_33, etc.). See EMTDC System Dynamics for more.
The node label also includes an optional voltmeter to measure node-to-ground voltage.