The Current Transformers (CT's) are the sensors used by the Gen 2 to measure power in real-time. They're filled with a magnetic material called Ferrite that contains special properties that allow us to measure alternating current flowing through a circuit line or wire. They're split-core, meaning they snap apart at the sensor itself, so they can be clamped directly around the circuit line without requiring you to detach the circuit line or performing any electrical work.
The "200A" CT's are designed to be placed on the system main lines and will measure up to 250A when installed in the Gen2's top ports. The "50A" CT's will measure up to 75A. If that amperage/current limitation is passed, no damage will occur to either the Gen 2 device or the sensors since they're passively monitoring power, but the measurements will max out at those amounts respectively. One important thing to note is that the amperage limitation is not of the sensor but of the Gen2's device ports. That means that using a 200A CT on a Gen 2 side port (designed for the 50A CT's) will still only reach 75A before maxing out its measurement capacity.
How many 200A CT's are needed?
This depends on the phase count of your system. One 200A CT sensor per phase/live main line. (neutral and/or ground lines are not included as a "phase")
Can I use a 200A CT on a side port?
Yes - you will need a 3.5mm female to 2.5mm male audio jack adapter for the different jack size (to fit the device port) and a 4.0 multiplier on the circuit to adjust for the different sensor size calibrations. Note - will still have a 75A limitation on the circuit (rather than 200A).
Can I use a 50A CT on a top port?
Yes - you will need a 2.5mm female to 3.5mm male audio adapter for the different jack size (to fit into the device port) and a 0.25 multiplier on the circuit to adjust for the different sensor size calibrations.
Flexible Sensors are a good solution for situations where access to the mains is restricted or they're hard to reach. While flexible sensors share many similarities to the regular 200A sensors, these sensors are technically called “Rogowski coils” (as compared to "Current Transformers", or "CT's"). They have a separate 120V power supply required to work properly which is included with the purchase of this sensor upgrade from our shop page.
Similar to the standard CT's, the Flexible Sensor's coil ring separates to allow you to attach the sensor without disconnecting the circuit line. To know if you have enough space for the Flexible Sensors, check the specs here.
Feedback and Suggestions
This knowledge base is pretty new for the Emporia team. Our goal is to provide all of the information we can to help you manage your energy in better ways. If this article wasn't helpful, or we could be more clarifying on any points please reach out to the Customer Support team and we'll certainly work to improve these guides.