DCM and Sub-Panels

I just installed my sense about 5 days ago. As it is just starting to discover devices (very cool BTW) I started reading about DCM’s I was wondering about sub-panels. I have a 200A Main Panel, and from that I have a 50A sub-panel and a 100A sub-panel.

The 50A breaker goes to a sub-panel in a small addition on my house that feeds just two rooms and a bathroom (a second master and a family room with a small gas forced air furnace).

The 100A breaker goes to a sub-panel in my
Garage that powers my Tesla 14-50 outlet and one other small outlet (currently) in the garage. I plan on possibly pulling a couple more circuits off of this panel, and eventually a second 14-50 when we get a Tesla for my wife.

In reading about DCM’s, it seems like I can add the DCM and leverage one of the flex cables to each panel.

Here is my question. Would installing DCM’s on the lines that go to the sub-panels be a benefit?

I have a sub panel off my main panel that powers my enclosed sun porch. The baseboard heaters on the porch was one of the first things Sense identified. I don’t see why you would need to add DCM’s to your subpanel.

I would only do so if there is some large load on a subpanel that Sense is not picking up through native monitoring. DCM works best when used to monitor a single load, not a group of loads. But, that rule could be broken if there is one major load on the subpanel (like an EV charger) and the remainder of the loads are inconsequential (garage lights, etc.).

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My 2c. DCM is a benefit on a sub-panel if that sub-panel contains a bunch of devices that you are OK bucketing together into one measurement / bubble. Once you put all those devices contained in the sub-panel onto one DCM, native detections for the same devices need to be merged into the DCM to avoid double counting. So you are (somewhat) giving up tracking individual devices in favor of a much more accurate view on the whole subpanel. I say somewhat, since you can still break them out again separately, at least on a temporary basis - the history for each is collected, but overridden by the more accurate aggregate subpanel measurement when you tell Sense that that device is part of the subpanel.

A caveat - Sense only allows you to monitor 240V with a single sensor CT if your panel is balanced (no neutral). You can violate this rule but your results will lose accuracy in proportion to the current on the neutral wire. Tesla chargers are balanced loads, but other 120V loads on that panel will unbalance it.

My thoughts based on my experience with my 2 Teslas, is that putting your garage on DCM might be useful to see your EV charging more accurately. Sense has scored detections on both my EVs over time, but never really nailed either one accurately.

Thank you all for the insights. I am only 5 days in so my Sense has not developed an affinity to most devices in my house. The 50A panel I have in the addition houses a gas forced furnace A/C and much of out “TV stuff”. The 100A panel mainly is there for the Tesla. I use the 32a mobile charger nightly.

Interestingly, Sense found my well pump first and then my GDO… right now I am trying to confirm if a consistent 1min pulse is from my water heater or my radiant heat motor pulsing to continue to cycle water through the system. I may not be able to “un-guess” that device until my radiant heat boiler goes offline late spring early summer.

I did not realize that if I started monitoring as a DC it would lump everything on the circuit into one group opposed to just aiding discovery of the devices up-stream from the DCM.

I am considering getting the TPLink Kasa power strip for the devices in the TV room to get those broken out. As well as a 115 for each of my fridges and deep freezer… but that may not be necessary based on some of the comments.

I appreciate the information and the community!

The HS300 smart strip is my go-to recommendation for those densely-populated entertainment centers and offices.

Depending on what type of fridge you have, I might recommend giving Sense some time to natively detect it before going to KP-115’s, but it won’t hurt. I’ve noticed that for folks with traditional fridges, compressors are one more our most solid detections.

Given you are still relatively early in your Sense experience, I would recommend waiting a bit since your are going to have a bunch of new detections and a better view of what Sense might be missing after a few months. My advice is to get a KP115 first to use a roamer or traveller. Connect it to Sense by turning on the integration, then plug it in to each device you might want to monitor for a couple day. Sense will give you the history for that period, plus the Always On for that device. Sense has a limit of about 20 smartplugs where an HS300 counts as 6, even if some of the plugs are unused, so the roamer measurements will help you use smartplugs more judiciously with Sense (don’t bother with a cluster of devices that aways add up to between 40 and 60W (my networking closet - I wasted an entire HS300 on that). More wisdom in the thread below.

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One more note - smartplugs and DCM don’t exactly lump all the native detections into their numbers - the user manually tells the smartplug/DCM which native detections are connected via the smart plug or DCM. You’ll want to do this because otherwise Sense will show a bubble for each (panel, plus individual detections) and the usage numbers from the detections will be double counted. But the individual detection are still collected in the Sense history, and the history can be revealed if you temporarily remove the device from the smartplug/DCM

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