Table of Contents
The power monitor supports six total current sensors. Here are three different monitoring approaches (you can combine all three of them)
Only AC sources can be monitored with this project.
For whole-home monitoring, you don’t need to monitor every circuit. You can capture your entire home’s usage just by measuring the main feed (or both main feeds if in North America). The “mains”, as they’re referred to, connect from the electrical meter to the main breaker in your panel. I will assume that you are in North America with a 120V, 60Hz grid connection, delivered over two legs. If you are outside North America and have a grid voltage of 230V at 50Hz, you will only have one main (unless you have three-phase service).
If you are more interested in specific usage for items like electric-vehicle chargers, air-conditions & heat pumps, etc, make sure you can identify the circuit breakers that power those specific circuits.
The power monitor supports monitoring production sources, like any grid-tied solar inverters, generators, or wind turbines. The data from these sources are used to calculate your net power, by default, but you can track them separately. When planning to monitor production sources, make sure to identify the breakers that connect to those systems.
As mentioned above, whole-home monitoring requires only to measure the mains. So, note the rating of the big main breaker that feeds the panel. The labels are often stamped directly into the toggle switch of the breaker, or on the circuit breaker body itself.
Next, make write down the rating of any additional circuits you want to measure. Also make note of the “width” of the breaker (is it 1-pole, or 2-pole?) You should have something like this:
- Mains: 200A (typically always 2-pole in North America)
- Solar Inverter: 80A (2-pole)
- AC Unit #1: 30A (2-pole)
- Master Bedroom: 15A
- Electric Vehicle (EV) Charger: 60A (2-pole)
The list above will be used as a sample configuration throughout the rest of the documentation.
With the two mains, and four additional circuits, this will fully populate the monitor’s six inputs.
Next, your electrician will need to de-energize the panel and remove the panel cover to check the diameter of the mains. Even with the main breaker turned off, the mains are still live, so the electrician will still need to excercise extreme caution in working around the mains. The diameter of the mains is important to check so you know what size sensor to purchase.
The final part of the plan is the location to install the power monitor. The sensor wires are only 2 meters long, but they can be extended by attaching the leads to a shielded cat5e cable. The Power Monitor needs two outlets - one to power the Raspberry Pi, and one to measure the grid voltage via the 9V AC step-down transformer. I highly recommend mounting a 200mm H x 155mm L x 80mm D ABS plastic junction box near the panel and an existing AC outlet to house the power monitor and cabling. The enclosure should not be installed in direct sunlight to prevent overheating, so indoors is ideal.
Now that you have your plan, you’re ready to purchase the hardware.
If this page did not answer your questions for planning, please see the FAQ.