Dual pole (and multi-pole) circuits are the kinds of circuits in your panel that include two lines (or more) to power the connected appliance/load.
Above: Highlighted dual pole breaker. It is not uncommon for dual pole breakers to have a "tab" that connects the two breaker switches together so if either trips, they both do.
There are two ways these types of circuits can be monitored with a Gen 1 or Gen 2 device:
1.) The first and most accurate method to monitor these kinds of circuits would be to attach a single sensor to each leg of the circuit. This method will accurately capture the measurements of the entire circuit. Right now in the application, they'll show up as separate circuits, but we're working on including the functionality to "combine" circuits within the app for easier viewing.
Above: Two sensors with one CT placed on each leg of the dual pole circuit. No multipliers are required in this scenario.
2.) The other method of monitoring these kinds of circuits involves using a single sensor on one leg of the multi-leg circuit and setting a multiplier in the application. This is a great way to conserve a sensor to use to monitor a different circuit, but it can add some inaccuracy to the measurements as we're "assuming" equal usage on the other leg of the circuit. In many cases this is an acceptable assumption as the difference will be negligible. However, for appliances with a neutral return, the difference can be quite large. Sub-panels can have very large differences between the two lines of service, so it's generally recommended to not use multipliers on these kinds of circuits. More details about using multipliers can be found here.
Above: One sensor attached to a single leg of the two leg, dual pole circuit.
Below: Highlighted screenshot of settings in App to set multipliers for circuits.
To set a multiplier in the app for a specific circuit, we can do the following:
- Select the Menu (☰) in top left corner
- Select Manage Devices under Settings
- Select device you want to make changes to
- Select circuit you want to add the multiplier to
- Change multiplier field to 2.00 (for dual pole breaker) and hit Save
It comes down to a trade-off between accuracy and sensor count. The "correct" implementation is the one that best suits your energy monitoring goals. If you have any questions or would like more clarification on how to monitor a dual pole (or larger) circuit, feel free to reach out to the Emporia Support team directly.
Multipliers for single phase:
If you're in a single phase system, you should not need to use multipliers and can leave the multiplier field at the default value of 1.0.
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.