Hi,
One quick doubt : If the Shelly 3EM allows to monitor 3 lines, I could buy and install 2 Shelly 3EM to monitor 6, and so on, right ?
I have the main line and 6 sub-lines I’d like to be able to monitor independently, that would mean 14 CTs to install, I’m not sure this module would be the best / most affordable way… But I am a newby in electricity monitoring so…
Thanks
Yes, you are correct.
I have currently 3 Shelly 3EM. They measure one heat pump, a two log houses independently. To measure the property’s total grid/import/export I use modbus via the my SolarEdge inverter and a meter connected that way.
Ok so I guess I’d also need 3x 3EM for 9 circuits all in all (I have 1 phase at home). Main circuit from public network and 8 sub-circuits in house.
I would not know how to use the modbus but I guess I wouldn’t have to anyway as I would only be monitoring the circuits the simple way (one CT for each, 3 circuits on each 3EM, all of that going to HA and configuring HA to make sense of all the data).
Are there good tutorials on how to connect everything ? I’m no electrician but it does not seem so complicated (apart from knowing where to connect each cable on N, VA, VB, VC, I and O)
@amitfin You seem pretty familiar with the 3 phase version. Can you explain what it going on with mine?
Why is there ‘energy returned’? I have no solar or anything like that .
Why is power negative sometimes ?
Is my house wired wrong?
@ianadd, the wiring is probably wrong. My bet is that VA, VB, and VC are not synchronized with A, B, and C.
I’ve asked a question about 3EM wiring, and you can find in the comments the relevant explanation (here).
Thanks, I’ll try asking questions there.
A small amount of returned energy can be leaked, if you have (like me) a heat pump or something with an inverter connected to the Shelly 3EM. That’s inevitable. But in your case try to just turn the clamps the other way…?
If the clamps were the wrong way round then surely the reading would always be negative. But I can get negative and positive power values on the same channel depending on what I am using. Current and volts always show positive. The shelly app shows the same problem. The issue is not in HA.
@amitfin Having re-read your comment I am going to have to check if the wiring is mismatched between clamps and the device’s three supply lines.
Anyone have installation of 3EM with 4th clamp? I have installed one on neutral to detect possible leakage, but I do not see it anywhere in HA or even not in Shelly web interface. Any special process to ‘activate’ this feature?
OK, the alignment of the power feeds to the clamps sorted the negative numbers.
Still got energy returned sensors showing data. Can’t see that info in shelly app tho’.
Any ideas?
I am in an apartment block and each unit has a separate meter. So I will go read our meter a couple of times next week and see how well it agrees with shelly.
Great to hear! How much returned energy are we talking about?
Should’t that be Watt?
kWh is correct
I don’t think so. Power is W, energy is kWh.
Should compare power (kW) from Shelly dashboard (local web server or cloud) with power from Home Assistant dashboard.
Should compare energy (kWh) from Shelly dashboard (Shelly cloud) with energy from Home Assistant dashboard.
Well, it looks very high to be any type of inverter disturbing the measurements… You do not have any kind of heating/cooling equipment?
