I have three grid tie inverters connected to my grid thru standard AC plugs. The system pushes about 1kw to the grid during the day but during the night they draw a total of 45 watts from the grid. This has been confirmed by measuring the ac current in the ac cord with a multimeter and with a current transformer. I even placed a 5 watt resistor in series in the line to see if it would get hot - it did. Now the strange part. I have two of those common plug in the wall "Energy monitors". One shows the approximate 45w, the other shows 0w. I did a test with the mechanical kwh meter mounted on the house to see if it was registering the 45w. I turned all loads off in the house thru the breaker panel except for the breaker with the inverters on it. Then watched the dial on the meter for 20 minutes. It did not move. So I connected a 60w bulb (on an extension cord ) and stood by the meter and it turned about one full turn in 10 minutes. So,the inverters are drawing power from the grid at night but don't appear to be affecting the power companies kwh meter. I work in electronics every day but can't understand this, can you explain what's happening?