Dual breaker boxes

installation

#1

Just installed Sense, first time poster.

My house has two 200A breaker boxes with separate feeds from the meter. One holds all of my 240V items like heat pumps, water heaters, etc. The other is the usual household 110 circuits. I elected to install the sense in the second panel because it is probably the most interesting, but I am very interested in what goes on in the other half as well. So, question:

  1. Is there a way to get a second set of leads so I can monitor this half? Or do I need a second Sense?
  2. If I got a second Sense, is the app smart enough to know that my house has two Sense devices?

Kind of bummed to discover this but still hopeful I can learn some things.


#2

You are going to need a second Sense unit and another Sense account. Currently the Sense app does not support more than one unit, although there have been several request for multiple unit support.


#3

1agkirk2 is correct. Unfortunately right now you would need two Sense accounts to track two different monitors. We do have plans to add multi-monitor functionality, but that’s still at least a few months out.


#4

I have have two 200 Amp breaker boxes and 2 sense units and 2 sense account. I would love to have both breaker boxes in one account.

Ed


#5

Putting on my research-mode EE hat, I’d think that the IDEAL Sense configuration would be to have a set of current sensors (the ‘collar’ device, but smaller than the ones monitoring the main feed) for each single-ended branch circuit.

My assumption is that the information from the main feed will typically be able to identify the devices on the two-phase circuits (ganged breakers) because they are usually feeding a single device (e.g. HVAC, Electric Oven, Electric Dryer, …).

Monitoring the current on the other circuits, though, ought to allow quicker & more accurate identification of ‘similar’ devices, such as ceiling lights on one branch vs ceiling lights on another branch, or the use of a hair dryer in one bathroom/bedroom vs. another bathroom/bedroom (when they’re on different circuits).

That is a rather significant technical challenge, I know, to provide both cost-effective sets of sensor leads (probably cabled in groups for ease of installation and connection), the size of the sensors (so they’d fit in the electrical box), as well as the connection ports to the Sense device itself.

Maybe that’s the “second generation” version of sense. If it could be done for, say, only a 50% increase in price – I’d choose it!

Even if there is only the capacity to monitor, say 16 of 24 branch circuits, by careful choice of which branch circuits are monitored, I’d think the device detection could be much more accurate and faster. (e.g.: I might not chose the circuit for the garage, for example, because the primary items on that branch may be the opener and one exterior light.)


#6

One possible enhancement that would not require hardware changes would be to allow the second set of CT’s supplied in the solar version to be used for a split or second main instead when the home has that but no solar. This would “just” be a programming or software change. You can already intelligently figure out where my solar and mains CT’s are connected from the variety of possible connection methods.


#7

You’re assuming that solar sampling is done at the same rate as the mains. I’m betting that it is done at a lower rate, squeezing in just a little sampling in-between main samples, given the the hardware I’ve seen int the probe.


#8

@Dan.C

While they don’t do device identification based on electrical signatures, there are systems whose installation/setup is similar to what you’ve visualized, such as those sold by Brultech and The Energy Detective.


#9

@Dan.C,

I was considering trying to build a Sense-based “ground truth” probe by doctoring a regular Sense unit:

  • Snip away the insulation into a short thick (industrial) 110V patch cord. One that is thick enough to fit snuggly inside a Sense
    CT.
  • Tap into the hot and neutral lines to power the Sense and supply sampled voltage. Only question is whether to live the second hot tap on the Sense empty or plug the same hot line from the cord into it.
  • Loop one of the CTs around the power cord to collect current info going through the cord.
  • Re insulate the tapped spot on the cord. And voila, a wall plug probe.

But then I speculated I might see heinous start-up issues with both scenarios related to the missing second voltage leg. Either the Sense wouldn’t see any voltage on the second leg or it would see a voltage that is either 180 degrees out of phase/wrong polarity with respect to the other leg or see no voltage.