Let's see your setup

Here is mine, the panel is inside a concrete wall, so I had to use the external antenna, when I tried with the antenna inside the panel and the panel closed I was unable to get a wifi signal. so I drill a hole and use the extension cable.

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New Install of Sense + Solar - 200 AMP recessed service with 11Kw 2 inverter PV system fed via 70 AMP 240v breaker. Sense is powered from an existing 240v breaker for a fully electric clothes dryer. I have a gas clothes dryer so that 240v breaker is technically not used.

Installation was fairly simple (about 30 minutes)

This panel is recessed into an exterior garage wall (pretty common in SoCal) Since the mains make a very tight bend (90 deg.) there isn’t room for both sensors above the breaker. I could have placed the main sensors inside the meter enclosure but found there was just enough room for them to sit loose around the unprotected bus bars.

The Solar sensors were actually more of a challenge to fit in, but with a bit of finagling, I was able to get them in place.

Keep in mind it is important that the sensors are completely closed. If there is any gap the current sense will be inaccurate. I had this issue when I allowed the panel cover to bump into one of the main sensors. Once support informed me of the issue, it was an easy fix to move the sensor to the side and close up the panel again.

I ran the wifi extension cable through the back of the panel into the garage since my network is all located on that side of the panel. A quick check test running the wifi antenna outside resulted in a weak signal.

The one thing that took a bit of work was enabling the solar. The first 10 attempts failed during the “Waiting for off” period. Since the PV system takes about 5 minutes to attempt to reconnect after powering down this wasted a bunch of time. For those that don’t know, you need to have PV output (150w or 500w depending on what instruction you read, I assume 500w min. as I had ~250w and it wouldn’t succeed) The setup instructs you to start the process, then shutoff your inverter(s) then if that works and it senses your PV is off it asks you to turn on your inverter(s). Since I couldn’t seem to get past the waiting for off part, I tried turning them off first. Then turned them on for 4 minutes of the 5 minute startup cycle and initiated setup. It was able to see the PV setup, then see it was off, then just when it wanted me to turn it on the 5 minute wait on the inverters was up and they started generating power. Voila!! Success… all up and running.

Finishing my solar install and it looks like I will have MUCH more room in my Solar combiner box than I have in the Main Breaker Panel. I haven’t put the cover back on the main breakers since I got Sense.

Waiting for my sensor extension cord to arrive so I can install the Sense into this box. I’m gonna run the power for the Sense off the 240v breaker that is coming from the solar panels as there is space on both sides of the screw to crimp down on wires. This will mean that the 30 amp main breaker for the entire PV system will be the only thing protecting me from a fire if there is a short in the Sense.

If you talking about using a breaker that is already in use for something else, might want to check on that. That would be “double tapped” and may not pass inspection.
I had originally setup my Sense on my water heater breaker. It will absolutely work but in the event we had a home fire or something and it had not been inspected, insurance could potentially not pay.

If you ha e space in another panel close, you could easily run Sense off dedicated breaker

New QO54 panel with Sense installed. All good so far!

Here’s two Sense monitors in the same load center.

  • One of them is my “main” unit - it has the mains CTs over in the meter box (pre-meter) and the solar CTs next to the solar feed-in breaker.
  • The other one is my “dual 400A unit” - it has CTs on the feeds to both my parallel panels, but does not monitor the solar backfeed so I only see “net meter” results, not Total Usage on that one. Hope to use the unit for other purposes someday, but wanted to help with the 400A beta, since I had been pushing hard for that feature.

Solar backfeed on the lower left.

Inside the meter box - CTs on my pre-meter mains

The $$$ are flashing before my eyes with all those QO AFCI/GFCI breakers you have. I have no doubt you were brought up to code!!!

Another 54 space QO here at my house:

I do have a sense but this Pic is not sense related directly but you guys still may geek out on it so I will sharr



A taplblet running a grafana dashboard switching between amp load and watt draw per breaker

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I’m jealous

I installed Sense last week and it began working immediately without issue. One of the best purchases I’ve ever made. :))

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Mains at the top, solar at the bottom. You can also see a second set of sensors on the mains (black square ones) installed previously by Tesla when they installed my solar.

This worked for 6 hours and then started giving me negative wattage numbers for the mains. The solar numbers always look right. When solar output is zero, the mains sensors display the negative of the actual mains wattage. When solar is nonzero, the mains sensors display some sort of addition of the mains and the solar, but not just a straight addition. Nothing I can figure out. Support has been contacted.

EDIT: I’ve since figured out that what it’s plotting for Consumption is actually the equation: 2*production-consumption. I’ve described this in a separate post with some screenshots.
EDIT2: Support was able to quickly fix my initial calibration problem.

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Hi Don - that’s a busy box! :))

Although it may be due to the picture or my eyesight, but it appears that the two 50A double pole breakers on the right show evidence of overheating on the wire insulation.

If it’s just the way the picture came out, then great, otherwise I’d suggest:

  1. Turn off the breakers, remove and inspect both the breakers and the wires. Clean as needed, preferably apply a small amount of dielectric grease on the contact areas, then reinstall with good torque on the breaker screws.

  2. Go to the other end of the wires (heaters?) and check those ends as well for overheating. If needed, correct as above.

Resistance is the enemy and wire termination points are the usual culprits. Electricians can get in a hurry or distracted and don’t always tighten the breaker screws as they should. Check all neutral and ground screws as well.

Why does a high resistance, high current connection get hot?

Heat is generated by electron flow across a conductor as it encounters resistance. Because energy is conserved, if some of the current cannot pass through the conductor, that portion of the electrical energy is converted into heat. Those heavy cables feeding your 50A breakers have very little resistance, thus pass most of the electrons with little heat generation. If a breaker screw is loose or the connection is otherwise compromised with increased resistance, that heavy cable effectively becomes much smaller at the point of contact and things heat up. Past a certain point, it will become catastrophic because the increasing heat also increases conductor resistance, which creates more heat, and…

If you do find loose breaker screws, I’d get the service turned off and check the torque on the mains and neutral/ground lugs as well.

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My 2c. 95% of the time, the automated setup Procedure gets the polarities and matching between phases/legs-L’s correct for solar. If not, support will straighten out once the vacation weekend is over.

To: @don.mathis
After @lholland pointed out the damaged wires, I took a closer look for myself. I agree with all of his comments. You need to check that connection immediately. I have installed 20+ residential breaker panels. The one issue that always occurs is getting the breaker screws tight. Copper is a very soft metal. You can tighten the breaker screws to the correct torque, then 30-minutes later you will discover that the metal has ‘oozed’ out and the connection is loose again. I always re-tighten the terminal connections 3 times and will have someone check my work before declaring the work completed. Follow @lholland 's instructions!

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Here is a closer look at those 50a breakers. What do you think? I have no experience with this so I can’t judge. I always call electricians. A year ago I had a new 240v outlet installed for my EV. Then, Tesla installers were here a few months ago to install the solar in the far bottom right breakers. And 2 days ago a local electrician installed the Sense in the two 20a breakers on the right (the only red wire you can see here and the breaker above it. ) Did all three of those visits miss a real problem? If so then they really do just put blinders on, don’t they?

The top 50a breaker goes to my fairly new electric range. The lower goes to a sub panel. When they installed my EV outlet they had to decide whether to run it off the sub panel (which they did not), so they had reason to look at the sub panel connection at that time, I imagine.

What exactly are you seeing in the pics? Is it the shininess at the ends of those wires?

Thanks!!
image|375x500

Exactly! That insulation material is designed not to catch fire, but I’d still shut both those 50A breakers off until it’s repaired. Those breakers only cost about $11 each at Home Depot, so have them replaced. Dcdyer’s post is excellent - I really like that idea of checking breaker screw tightness several times until the wire is fully compressed.

You’re a wise man letting others stick their hands in there - just start checking their work with what you’ve learned. :))

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Well, we looked again and what looks like melted plastic at the end of the wires is some kind of goo that has been applied there. Perhaps it’s the dielectric grease you mentioned. It’s a bit slathered onto the ends, and further along from the end we touched it and it’s a liquid black goo. It would have not been liquid if it had been melted plastic.

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Great news Don - I believe it! :))

I knew I could be wrong when I first posted about this, but I felt like it would be helpful to discuss the issue regardless given the amount of participation around here and the fact that loose breaker screws are a real and common problem.

If you’re like many of us (geeky, into toys), keep that panel cover off for a while and when Sense shows significant power usage, have a look at the breakers and wiring with one of these to find heat problems before they manifest into something worse.

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