Hello and happy holidays.

I am using a WEM3080 single-phase energy meter on a 3 wire system setup as per the following link:

https://www.iammeter.com/newsshow/single-phase-three-wires-system

The issue I am having is the readings reported don't match my utility company readings for grid consumption.  For example: on Dec 8 my utility meter reported 24 kWh while the WEM3080 reported only 16.6 kwH.

Any suggestions will be greatly appreciated.  I already check my cabling. 

Thanks,

David

Hi:

The premise of this method is a balanced consumption in the dual phase. (Please see the reminder in the red rectangle).
If the grid`s consumption is not balanced, this method will not be accurate. 

If you used a dual-phase inverter, you can measure its total output in this way, because the output is balanced.
But for the grid consumption, most of the grid consumption would not be balanced in the two phases, except in some special scenes(only some balanced loads are connected in the grid).

Strong recommend using this method to measure the grid consumption for the dual phase system 

 Monitor the system of 120/240V or 120/208V in North America.

Have a nice weekend.

I now understand I made the wrong decision to purchase a single-phase unit for an unbalanced 3 wire system.   Somehow I don't remember seeing the warning on the solution page.  In any case, thanks

To solve this issue I need a 3-phase meter which is fine.  I am however have a separate 1-phase meter on a sub-panel and reading the power provided by a solar panel system.  Sub-panel is a few meters away.  Hence, I have the follow up questions:

- will the combination of a single-phase meter to measure the PV wattage and a 3-phase meter for the grid cause an issue?

- what would the wiring look like?

- are Visio or power point icons for the meters?  I would love to illustrate my setup.  

Thanks,

-dc-

Hi:

- will the combination of a single-phase meter to measure the PV wattage and a 3-phase meter for the grid cause an issue?

no problem would be caused

- what would the wiring look like?

If you also have a dual-phase inverter, you can install the single-phase  on the inverter output, using the cost-effective method described in  https://www.iammeter.com/newsshow/single-phase-three-wires-system

Because the inverter output is balanced, this method would correct.

- what would the wiring look like?

You can use one WEM3080T to measure the dual-phase grid, and one WEM3080 to Measure the solar inverter output.