Negative 'not_measured' values

[josharmour]

I have very basic setup for now.

Both of my mains are measured and then I have ct’s on several of my breakers (some our doubled because they are a double breaker like my tesla charger).

I have a couple basic ouputs so that I can trace out what is not being measured.

Measured Watts = Breaker_1_3_Dryer + Breaker_5_7_Bathroom_Heater + Breaker_9_11_Oven_Upstairs + Breaker_17_Sub_Panel_Furnace + Breaker_19_Washer + Breaker_21_Upstairs_Kitchen + Breaker_23_Upstairs_Disposal + Breaker_25_Garage + Breaker_27_29_Tesla_Charger + Breaker_28_30_Down_Disp_Dishwasher + Breaker_20_22_Down_Kit_Hood_Fridge + Breaker_2_4_Lighting_Down_Laundry_Bed_Office abs

Not_Measured Watts = (Main_1 + Main_2) abs - (Breaker_1_3_Dryer + Breaker_5_7_Bathroom_Heater + Breaker_9_11_Oven_Upstairs + Breaker_17_Sub_Panel_Furnace + Breaker_19_Washer + Breaker_21_Upstairs_Kitchen + Breaker_23_Upstairs_Disposal + Breaker_25_Garage + Breaker_27_29_Tesla_Charger + Breaker_28_30_Down_Disp_Dishwasher + Breaker_20_22_Down_Kit_Hood_Fridge + Breaker_2_4_Lighting_Down_Laundry_Bed_Office) abs

Total_Usage Watts = Main_1 + Main_2

What I’m noticing is that my Not_Measured is negative once in a while, specifically it seems like when my Tesla charger is going.

I added in the ‘abs’ functions just in case if a negative value is causing an issue, or if I had the values reversed (total usage and total measured)…

Still getting a negative value from time to time on ‘not_measured’.

Maybe doubling one of the wires for my Tesla Charger is wrong?

[josharmour]

[josharmour]

[josharmour]

Actually even when the Tesla Charger is not running, I’m seeing this issue. Example attached.

[overeasy]

It’s hard to put these graphs into perspective because the y axis labels are cropped off. I don’t know if the last plot is just a few Watts or something more significant.

Does your Tesla charger have two or three wires? In other words, is there a white wire in addition to a red and black?

[josharmour]

Yes, it’s an nema 14-50.

[overeasy]

Can you update those graphs, especially the last one, so I can see the Y-axis?

[josharmour]

[overeasy]

That’s not what I was looking for. Can you post a Graph+ of that same time period with the following sources:

Main_1
Main_2
Breaker_1_3_Dryer
Breaker_27_29_Tesla_Charger

Can you click the CSV tab, download it, and upload that file.

Also, can I see your inputs setup page,

[josharmour]

Not sure where the CSV Tab is. Looking for that now.

[josharmour]

I was able to use the file manager to copy the code is the config.

{
“format”: 2,
“timezone”: “-7”,
“update”: “MINOR”,
“device”: {
“name”: “IotaWatt”,
“version”: 3,
“channels”: “15”,
“burden”: [
0,
20,
20,
20,
20,
20,
20,
20,
20,
20,
20,
20,
20,
20,
20
]
},
“inputs”: [
{
“channel”: 0,
“name”: “Input_0”,
“type”: “VT”,
“model”: “TDC DA-10-09-E6”,
“phase”: 0.07,
“cal”: 10.79
},
{
“channel”: 1,
“name”: “Main_1”,
“type”: “CT”,
“model”: “ECS25200-C2”,
“phase”: 1.7,
“turns”: 4000,
“cal”: 200
},
{
“channel”: 2,
“name”: “Main_2”,
“type”: “CT”,
“model”: “ECS25200-C2”,
“phase”: 1.7,
“turns”: 4000,
“cal”: 200
},
{
“channel”: 3,
“name”: “Breaker_1_3_Dryer”,
“type”: “CT”,
“model”: “AcuCT-H040-50”,
“phase”: 1,
“turns”: 1000,
“cal”: 50,
“double”: true
},
{
“channel”: 4,
“name”: “Breaker_5_7_Bathroom_Heater”,
“type”: “CT”,
“model”: “AcuCT-H040-50”,
“phase”: 1,
“turns”: 1000,
“cal”: 50,
“double”: true
},
{
“channel”: 5,
“name”: “Breaker_9_11_Oven_Upstairs”,
“type”: “CT”,
“model”: “AcuCT-H040-50”,
“phase”: 1,
“turns”: 1000,
“cal”: 50,
“double”: true
},
{
“channel”: 6,
“name”: “Breaker_17_Sub_Panel_Furnace”,
“type”: “CT”,
“model”: “AcuCT-H040-50”,
“phase”: 1,
“turns”: 1000,
“cal”: 50
},
{
“channel”: 7,
“name”: “Breaker_19_Washer”,
“type”: “CT”,
“model”: “AcuCT-H040-50”,
“phase”: 1,
“turns”: 1000,
“cal”: 50
},
{
“channel”: 8,
“name”: “Breaker_21_Upstairs_Kitchen”,
“type”: “CT”,
“model”: “AcuCT-H040-50”,
“phase”: 1,
“turns”: 1000,
“cal”: 50
},
{
“channel”: 9,
“name”: “Breaker_23_Upstairs_Disposal”,
“type”: “CT”,
“model”: “AcuCT-H040-50”,
“phase”: 1,
“turns”: 1000,
“cal”: 50
},
{
“channel”: 10,
“name”: “Breaker_25_Garage”,
“type”: “CT”,
“model”: “AcuCT-H040-50”,
“phase”: 1,
“turns”: 1000,
“cal”: 50
},
{
“channel”: 11,
“name”: “Breaker_27_29_Tesla_Charger”,
“type”: “CT”,
“model”: “AcuCT-H040-50”,
“phase”: 1,
“turns”: 1000,
“cal”: 50,
“double”: true
},
{
“channel”: 12,
“name”: “Breaker_28_30_Down_Disp_Dishwasher”,
“type”: “CT”,
“model”: “AcuCT-H040-50”,
“phase”: 1,
“turns”: 1000,
“cal”: 50,
“reverse”: true
},
{
“channel”: 13,
“name”: “Breaker_20_22_Down_Kit_Hood_Fridge”,
“type”: “CT”,
“model”: “AcuCT-H040-50”,
“phase”: 1,
“turns”: 1000,
“cal”: 50
},
{
“channel”: 14,
“name”: “Breaker_2_4_Lighting_Down_Laundry_Bed_Office”,
“type”: “CT”,
“model”: “AcuCT-H040-50”,
“phase”: 1,
“turns”: 1000,
“cal”: “50.00”,
“reverse”: true
}
],
“outputs”: [
{
“name”: “Measured”,
“units”: “Watts”,
“script”: “@3+@4+@5+@6+@7+@8+@9+@10+@11+@12+@13+@14|”
},
{
“name”: “Not_Measured”,
“units”: “Watts”,
“script”: “(@1+@2)|-(@3+@4+@5+@6+@7+@8+@9+@10+@11+@12+@13+@14)|”
},
{
“name”: “Total_Usage”,
“units”: “Watts”,
“script”: “@1+@2”
}
],
“dstrule”: {
“adj”: 60,
“utc”: false,
“begin”: {
“month”: 3,
“weekday”: 1,
“instance”: 2,
“time”: 120
},
“end”: {
“month”: 11,
“weekday”: 1,
“instance”: 1,
“time”: 120
}
}
}

[overeasy]

@josharmour

Not sure where the CSV Tab is. Looking for that now.

It’s the CSV Data tab below the graph.

For the inputs config was looking for this

and might as well post the same for outputs.

I think I see the problem but need to quantify it with the CSV data.

[josharmour]

Here are my inputs

Here are my outputs

[josharmour]

I’m trying to attach the csv, but it wont let me on the file upload button here.

iotawatt_2021-10-01_1359

[overeasy]

That’s it I have the CSV now.

[overeasy]

That doesn’t appear to be the CSV for this plot:

It has five traces, doesn’t appear to have one of the mains, and I think has your not measured.

Please recreate the plot above and post it again along with the CSV. This is very difficult to follow when things keep changing.

EDIT: You should be able to upload .CSV files now.

[josharmour]

Ok I did my best to recreate it.

Note this isn’t one of the charts that show the negative on my ‘not measured’ output…

Here it is.
iotawatt_2021-10-01_2123.csv (40.1 KB)

[overeasy]

OK, there are a couple of things that I can see. They may not account for all of the variation, but lets see what happens when you address these.

You have a single CT on your dryer and you are doubling it. A dryer uses 240V for the heater, but only 120V for the tumbler motor. You seem to have the CT on the side that is both 240V and 120V, so your dryer input is overstated by hundreds of Watts. See the documentation about the various ways to measure three-wire 240V circuits.

I suspect that the clamp type CT on one of your mains is reading low. With the clamp type this can be because the clamp is not fully closing due to interference. They are shipped with small pieces of paper between the mating surfaces. Sometimes they dont fall out during installation and interfere with the two halves mating properly. I’d suggest you remove and reinstall both being careful to inspect for that paper and being sure they mate and won’t be disturbed when you put the cover back on the panel.

The Tesla has a three-wire plug, but I’m not sure if it uses the neutral. It appears to do so in the CSV, but not conclusively because of the suspected low reading main. If it does use the neutral, you will need to treat it as a three-wire 240V load.

The oven may also be a three-wire load. You should check that.

[josharmour]

Thanks so much for helping here, I do think after reading your reply and reading more about 3 wire 240v in the guides that I am not suppose to be doubling a single leg.

Based on my pics below I think that my Tesla, Oven, and Dryer are all 3 wire 240 volt appliances.

Definitely the Telsa charger, as it has red/white/black that were all wired to the panel with the white on a neutral bar. I suppose that the dryer and oven are also ran the same way, however I can check for sure. The Tesla plugs in to the same exact plug type as a conventional dryer so I think that it is wired the same.

Here are some pics of my panel, the Tesla charger is the lowest on the left side.

[overeasy]

The Tesla charger uses a three-wire plug but may not use the neutral. After you check the mains, it should be possible to tell. For that matter, if you were to move the CT from the black wire to the white wire, you will see zero if it’s not used (while the charger is on of course).