Current transformers are passive sensors that are installed around one of the conductors of a circuit. They are insulated from the high voltage of the primary circuit and sense the current in the wire by the magnetic field it creates. A safe low-power proportional signal is sent to the IoTaWatt.
One current transformer is required for each circuit to be measured. IoTaWatt has the capability to connect and measure up to 14 circuits.
It is recommended that where possible, current transformers be purchased with the original kit.