Team,

can you tell me PLS to where should I put the CT-s of WEM 3080T on in single phase system with backup PLS.

Grid-CT1, Solar Inverter AC -CT2, Solar Inverter backup - CT3 seems to me logical, but will it work? Do you have any special suggestion about implementation PLS.. 

Until now I had an on-grid inverter without backup, where wiring was Grid CT1, Solar CT2 (I have used CT3 for special load, but in general it was a surplus in this setup, but iammeter cloud was able to  calculate Export/import to Grid, Solar production, and Load from it. 

Now I have a hibrid inverter with 2 solar output (AC and Backup). Can I use WEM3080T as mentioned PLS?

Thank you Gabor

Hi Gabor, Yes, your proposed wiring will work. The WEM3080T's three CT inputs are independent measurement channels — the "Grid / Solar / Load" labels in the IAMMETER cloud are just default display names. Each channel simply reports the real-time power and direction it senses, so you can map them to whatever circuits make sense in your installation. For your hybrid inverter setup: - **CT1 → Grid** (bi-directional, same as before) - **CT2 → Solar Inverter AC output** (this is your normal solar feed) - **CT3 → Solar Inverter Backup output** (the emergency/backup feed) A few practical tips: 1. **CT orientation matters.** Make sure the arrow on each CT points in the direction of current flow *from source to load* on the circuit you want to monitor (grid side: arrow pointing from grid to your panel; inverter AC side: arrow pointing from inverter to your panel; inverter backup side: arrow pointing from inverter out toward the backup loads). If a value comes out negative, just flip the CT physically — no reconfiguration needed. 2. **Configure the channels in the cloud.** After wiring, log into the IAMMETER cloud, open your meter's settings, and rename the three channels so they reflect your real circuits (e.g. "Grid", "Solar AC", "Solar Backup"). This makes the dashboard and history readouts accurate. 3. **Total solar = CT2 + CT3.** The cloud will show two separate solar readings rather than a single combined figure. If you want the auto-generated "Self-consumption / Export / Import" calculations to remain correct, add CT2 and CT3 together mentally for total PV production; the grid and load formulas still apply the same way because the meter only knows net power on each CT. 4. **Load calculation caveat.** With both PV outputs metered, the cloud can't independently derive total household load (it doesn't know how the two inverter outputs share loads). If accurate load breakdown matters to you, the standard approach is to meter Grid + the two inverter outputs and accept that "load" is the residual sum. For most users this is sufficient. 5. **Firmware.** Make sure your WEM3080T is running a recent firmware (≥ i.91.065.x) — there have been improvements to bi-directional detection and cloud labeling that make setups like this cleaner. Short answer: your CT1/CT2/CT3 plan is exactly right and will give you Grid import/export, Solar AC production, and Solar Backup production as three independent readings. --- 🤖 Reply auto-generated by IAMMETER bot

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🤖 Reply auto-generated by IAMMETER bot

thanks bot...

Is it possible, that I put CT1 on Grid wire, and I clamp the CT2 on "Solar Inverter Backup and Solar inverter AC" at once... so two wires will run in CT2 what will represent the Solar production. Than I can use CT3 wherever I want (like measure special loads for example..) What is your view PLS, any suggestion or concerns PLS? Thanks

Yes, in principle you can pass both inverter output conductors through CT2 and measure their combined current, provided both conductors belong to the same phase and pass through the CT in the same current direction.

OK, can I configure  CT1 to Grid wire (mark as Type Grid), Ct2 to Inverter AC wire (configure as Type Inverter) and CT3 to inverter Backup(configure as type inverter)? Will it summarize CT2 and CT3 and show as Solar power? Will it calculate export/import and load correctly? Grid- Solar= load? with other words: CT1-(CT2+CT3)= load?

Hi Gabor,

Thank you for raising these points. Your questions have actually pushed us to move forward with a system upgrade.

We will evaluate the details and get back to you as soon as possible.

BR

Laoliu

Hi Gabor,

We discussed today and think the configuration below is the proper mode for you (based on current system`s features)

• CT1: Grid wire → Use Type = Grid
• CT2: Hybrid inverter AC/Grid port → Use Type = Inverter
• CT3: Hybrid inverter Backup output → Use Type = Load

I would not recommend configuring CT3 as another Inverter.

The reason is that the Backup output is actually supplying a separate backup load. If CT3 is configured as Load, Phase C will be treated as an independent special load and will not participate in the Grid/Inverter calculation.

With this configuration:

• CT1 will continue to measure Grid Import / Export correctly.
• CT2 will be used together with CT1 for the normal load calculation.
• The calculated Load in IAMMETER-Cloud will represent the main/non-backup load, i.e. the total load excluding the Backup load.
• CT3 will separately show the Backup load.

So conceptually:

Calculated Main Load = Grid + Inverter AC
Backup Load          = CT3
Total Household Load = Main Load + Backup Load

Please note that the sign of Grid/Inverter power is already considered in the calculation, so it is not simply Grid - Solar.

Also, because this is a hybrid inverter with a battery, the value measured on CT2 should be understood as the inverter's AC-side net power, rather than pure solar generation. Battery charging/discharging can also affect this value.

This configuration should therefore be more suitable than setting both CT2 and CT3 as Inverter.

Best regards,

Laoliu

Hi Laoliu, thanks for your fast response, I will use the suggested setup. (and yes I am aware that we are talking about AC side) 

Let me ask one more question PLS, did you ever try to make measurement on Neutral wire PLS? What do you think, if I put CT3 on N wire (just before PE and N will be combined and leave the house as PEN wire...) Than "special load" CT3  will show the household consumption exactly... what do you think, will it work? (actually it should provide the same result what you told, just I don't need sum up "special load" +"load", but "special load" will show on household consumption immediately..)

Hi Gabor,

I understand your idea, but I would not recommend putting CT3 on the Neutral/PEN conductor at that position.

In a simple single-phase load circuit, the current in L and N is indeed the same magnitude. However, in your system the Hybrid inverter is also connected to the AC bus.

For example:

Household load      = 10 A
Hybrid AC output    = 6 A
Grid import         = 4 A

At the Grid connection, the Neutral/PEN current will also be approximately 4 A, not 10 A.

The reason is that part of the load current is supplied locally by the Hybrid inverter. The main Neutral/PEN conductor only carries the net current exchanged with the Grid, in the same way as the Grid live conductor.

So if CT3 is installed on the Neutral just before N and PE are combined into PEN, it will basically measure another version of the Grid current, rather than the total household load.

There is also another reason I would avoid this point: close to the N/PE/PEN connection, depending on the installation, some current may have parallel paths through PE/PEN or leakage paths, so it is not an ideal point for accurate active-power measurement.

I would therefore keep the previous setup:

• CT1 → Grid, Use Type = Grid
• CT2 → Hybrid AC port, Use Type = Inverter
• CT3 → Backup output, Use Type = Load

Then IAMMETER-Cloud will show:

Calculated Load = Main / non-backup load
Phase C Load    = Backup load

Total household load
= Calculated Load + Phase C Backup Load

So although the total household load is not shown as one single value directly, both parts are measured and available separately, and together they represent the full household consumption.

Hi Laoliu you are right indeed, thanks for highlighting these points,