A negative kW reading is usually due to one of 2 things
The Current transformers (CT's) have been fitted onto the cable or busbar the wrong way round.
The P1 side of the CT should be towards the supply and the P2 side of the CT should be towards the load.
Alternatively, if the CT is fitted correctly, the problem could be due to the secondary wiring from the CT to the meter being incorrectly connected.
Please check the wiring diagram of your chosen model to confirm the current inputs are wired correctly.
The Current transformers (CT's) have been fitted onto the cable or busbar the wrong way round.
The P1 side of the CT should be towards the supply and the P2 side of the CT should be towards the load.
Alternatively, if the CT is fitted correctly, the problem could be due to the secondary wiring from the CT to the meter being incorrectly connected.
Please check the wiring diagram of your chosen model to confirm the current inputs are wired correctly.