Emporia Energy Community › Support Center › Hardware and Installation › 2 large A/Cs ?
- This topic has 11 replies, 3 voices, and was last updated 3 years, 2 months ago by
waterboyz.
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jj613
MemberI have an upstairs and downstairs A/C. I’d like ideas about the best way to sense these.
The two blowers each have a 240V 15A circuit. I’d hate to use 4 clamps for these, and I’m pretty sure I gathered from other posts that I can clamp just one side of each fan in the breaker panel and double it in the app … is that right?
The compressors have a 70 amp breaker feeding a subpanel outside with two 30amp breakers in it. Any suggestions about that? The subpanel is very far. The two devices might not use more than 50 amps together, so the Vue might function on the 70 amp breaker but it won’t distinguish between the two units.
Could I extend a pair of Vue sensors to the subpanel using phone wire? Would that work? Or are the sensors sensitive to cable length, noise, etc?
I can’t install a Vue outside for various reasons.
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Member
Actually, since they use audio connectors, I guess my approach would be off-the-shelf audio extension cables rather than phone wire. But aside from that the question is …. will that work and how long can they be?
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waterboyz
MemberJJ613 ssaid:
But aside from that the question is …. will that work and how long can they be?
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I have another device that uses CTs. That vendor said I could extend the wires to their CTs up to 36″. That may be an option.
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Member
I have a heat pump with a HUGE toaster as the backup heat. My system has 2 60amp double pole breakers plus the 30amp double pole for the outside unit.
So…..
That is currently burning up 6 CTs. I just got mine installed so I’m still learning it and collecting data. Probably I will run the individual CTs for a few weeks to get a pattern. Then I will use one CT for both poles of the breaker.
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@waterboyz you almost certainly don’t need to sensor both sides of these devices. You may as well prove it to yourself now that you have done it but you’ll be able to recover 3 of the sensors for something else, just remember to set the remaining ones on the 2-pole circuits as “2x” in the app.
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Member
In response to my own question: I learned that you may not run sensor wires, audio or telephone wire etc from the Vue to far away places outside the electric panel. The Vue and all its sensors and wires need to be treated as live AC power lines, and as such if you want to put sensors far away you need to run wires in conduit or to use NM/MC etc electrical cable to extend into another proper box. And then you have the issue of distance. I don’t know if I’ll end up trying this.
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Member
JJ613 said:
“you almost certainly don’t need to sensor both sides of these devices. You may as well prove it to yourself now that you have done it but you’ll be able to recover 3 of the sensors for something else, just remember to set the remaining ones on the 2-pole circuits as “2x” in the app.”
It has been less than a week but here are my results so far:
A/C – 1 = 52.942 A/C – 2 = 52.592
Water Heater – 1 = 22.089 Water Heater – 2 = 21.934
Well Pump – 1 = 1.097 Well Pump – 2 = 1.088
So, yes, I could pull one CT and use the multiplier on the other but I think I will let it play out a bit longer. I’ll be glad when the update to the app will allow combining but separate. As a technical OCD person, I just want to know just-in-case.
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Member
FYI the only 220V device where I thought I might need two sensors is my combo washer/dryer that has a neutral too, and according to its manual has some 120V circuitry inside, like the timer and the light in the dryer. So I did the same test as you. If I look as second/minute data I see differences but the week/month data is very balanced and I’m going to take one sensor off. 35.887 / 35.070. 1kWh/month difference, 2% .. not worth the sensor.
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Member
jj613 said:
FYI the only 220V device where I thought I might need two sensors is my combo washer/dryer that has a neutral too, and according to its manual has some 120V circuitry inside, like the timer and the light in the dryer. So I did the same test as you. If I look as second/minute data I see differences but the week/month data is very balanced and I’m going to take one sensor off. 35.887 / 35.070. 1kWh/month difference, 2% .. not worth the sensor.
I’m curious, does the multiplier have to be exactly 2x vs say 1.8x?
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scrambler
MemberAs far as I know you can set the Multiplier to whatever you like.
From what I read, this was actually used for Gen1 that used a fixed 120V reference to compute power, allowing people to correct the power calculation to account for a different value than 120V.
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Member
@waterboyz if I understand your suggestion, it’s a good one. I believe the app will let you set whatever factor you want. So I think you’re suggesting I monitor the laundry for a while and hopefully determine that actual total usage in practice is some specific factor of either A or B side, and so I pick the side and the factor and get better accuracy than 2X? I’m already set up to try that so away we go.
There will be some small inaccuracy, for example, the dryer light is on one side and if someone leaves the door open that will break the assumption but if I measure this over a couple of months, hopefully it will work out pretty accurate including averaging in typical events like the door being left open.
And I was just about to go repurpose one of the leads … I’ll leave it for a couple of months.
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