In a residential PV system, production CTs are required to measure PV generation?

• A. 3
• B. 2
• C. 1
• D. 0

Answer: (C)

PV generation in a residential system travels along a single current path from the inverter to the point of connection in the service panel. To quantify how much energy the PV system is producing for metering or monitoring, you only need to measure that one current path. A single production current transformer on the PV feed provides the necessary signal for the meter or monitoring device to calculate production. Adding more CTs would duplicate measurements and add cost without giving extra useful information in a typical single‑phase home installation. If you had a three‑phase or more complex setup and wanted per‑phase data, more CTs could be used, but for a standard residential system, one CT is sufficient.