What defines a secondary electric supply line?

A secondary electric supply line is defined as a lower voltage electric supply line. This distinction is important because secondary lines typically carry electricity from distribution substations to consumers and are designed to operate at lower voltages compared to primary lines, which carry high voltage electricity over longer distances.

In the context of electrical distribution systems, secondary lines are crucial for delivering electricity to residential, commercial, and sometimes light industrial customers. These lower voltage lines ensure that the electrical supply is safe and usable for end consumers.

Other options refer to different aspects of electrical infrastructure. For example, high voltage lines represent primary lines, which are essential in the transmission of electricity over vast distances but do not serve the purpose of directly supplying power at the usage level. Similarly, lines that connect directly to substations are typically classified as primary lines rather than secondary. Lines dedicated to industrial use are not specifically indicative of voltage levels and can be either primary or secondary based on the infrastructure design and requirements.