15/10/2026
A CT meter is an electricity meter that uses external current transformers (CTs) to measure high-current supplies safely. Instead of sending the full load current through the meter, CTs reduce it to a small proportional signal—commonly 1 A or 5 A—which the meter reads and multiplies back to calculate actual consumption.�
How it works
CTs are fitted around the main incoming conductors.
For example, a 300:5 CT reduces 300 A of actual current to 5 A at the meter; the meter applies a multiplier of 60 to calculate the real value.�
The meter records energy in kWh using this scaled current, so your bill reflects the actual electricity consumed.�
Where it is used
CT meters are typically used for larger commercial, industrial, apartment-common-area, or high-load connections—often where the service current exceeds about 100 A.�
Why it matters for solar
If you install rooftop solar on a CT-metered connection, the installer and utility must account for the CT ratio/multiplier in net-metering or billing. Otherwise, generation and import/export readings can be recorded incorrectly. CT metering is a system of CTs, a CT-rated meter/socket, test switch, and enclosure—not just the meter alone.�
