What is the tool used to measure the size of unmarked electrical wire?

The tool specifically designed to measure the size of unmarked electrical wire is the wire gauge. This tool is calibrated to determine the diameter of electrical conductors, allowing technicians to accurately identify wire sizes, which is crucial for ensuring the proper electrical load capacity and safety in electrical systems.

Wire gauges typically feature a series of holes or slots, through which the wire can be inserted. The appropriate gauge size can then be determined based on which hole the wire fits into most closely. This measurement helps in selecting the correct wire for applications based on current carrying capacity and resistance, which are vital for safe and efficient electrical installations.

While calipers and micrometers can also measure the thickness of wire, they are not specialized tools for wire sizing and may not be practical in every situation, particularly with unmarked wire. A multimeter is primarily used for measuring electrical values such as voltage, resistance, and current, rather than for gauging the physical size of wire itself.