What is a meter main and where is it used?

• A. A device that records only energy usage.
• B. A combined device containing the service disconnect and meter; used in some residential and commercial installations.
• C. A device that isolates ground faults.
• D. A switch that controls outdoor lighting.

Answer: (B)

A meter main is a single enclosure that houses both the electric meter and the service disconnect. This setup provides a central point to measure electricity usage and to shut off power to the entire building with one handle. It’s used in some residential and commercial installations where having the meter and the main disconnect in one unit is practical or required by the layout or utility practices, and it can be located either indoors or outdoors near the service entrance.

This differentiates it from a stand-alone meter (which only measures usage), from devices that isolate ground faults (like GFCIs/AFCIs), or from a switch that merely controls outdoor lighting.