What to do about more than 14 CTs and a subpanel

I realize that you could just select CTs to monitor just the breakers/circuits you WANT to monitor, but I would prefer to just monitor all of them.

What do you do when you have more than 14 breakers in a single panel, and when you have a subpanel with 8 additional? I understand you could put a CT in the main panel, but I would like to know what breaker/circuit on the subpanel I have concerns for.


You add more IoTaWatt and have them upload to influx or Emoncms to aggregate the data.

If I had a nickel for every variation of this question that has been asked… The sub-panel is a legitimate need, and if not close to the main panel would require another base unit anyway, but my standard advice to anyone that is contemplating monitoring every circuit in the house is to start with one unit and what you can monitor with that, look at the data that you get, assess the need for more detail and add more if appropriate.

There are several methods of combining circuits into one CT, and although the individual circuits loads cannot be identified automatically, most significant appliances can be identified in a daily usage graph.

I’m not in the business of selling a lot units. Rather I would prefer that you get what you need to manage your energy use.

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Personally, I love the granularity as well. That said, on a 42-circuit panel most people would be hard-pressed to identify 14 unique and meaningful individual loads. Example: You need two branch circuits (in the US) for kitchen counters. It is highly unlikely that both are separately meaningful. I have 4 circuits for interior lighting in a panel, same situation. Then there are 240V loads like water heaters, ovens, clothes dryers, and similar that only need metering on one pole.

That said, I do like having a dedicated CT on my garage door opener as it makes for a burglar alarm of sorts. I also like having one on each refrigerator and freezer so I can better watch how they are operating.

Going multiple units for a single panel is a bit of a pain today though… and it can be required if there isn’t enough cable slack to group circuits into a common CT… at which point you can end up running out of spce inside for the CTs.

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My sub panel is actually on an entirely different floor, so I would have to use two units.

Does combining multiple circuits into a single CT require rerouting? I don’t want to change how the box is wired. Sure some of the 15A breakers might be close enough together in the box to do this, but I’m guessing its going to most likely be installed where the wiring routes to leave the box.

One of the main reasons I’m looking at this solution is that I want all of the equipment and data on premises. I haven’t used influxDB in the past, but it appears I could set up up in a vm or in a container and do the data aggregation there.

There are likely some breakers/circuits that have little or no need for monitoring, I’ll have to go through them.

My biggest concern is that I use more power than most of my friends do…and some of them have much larger houses than I do. I’m trying to figure out what gear needs to be reviewed or replaced, or evaluate their purpose and true necessity. I have lots of computer and electronics gear.

The wires for breakers on opposite phases need to be in opposite directions through the CT, which was hard for me to do. It was easy to group same phase into a single CT with the way my wiring was done though.

For me, my network cabinet with router, modem, POE switch, and CCTV DVR uses ~4.5kWh/day, and my office with another switch, three NUCs, two NASs, and some home automation equipment uses 2.8kWh/day. My (subzero) fridge is about 3-3.8kWh/day, despite the EnergyStar value being closer to 1.5kWh/day.

(I run Influx on a Proxmox VM.)