[Governor Dinwiddie]

The “eco” power sources need to be synced with the grid frequency. In the USA,
if the grid is off by as little as 0.5 Hz, it is enough to trip safety circuitry.

[Tell It Right]

The “eco” power sources need to be synced with the grid frequency. In the USA, if the grid is off by as little as 0.5 Hz, it is enough to trip safety circuitry.

Agree. My solar inverter beeps and disconnects from the grid whenever it detects that the grid power deviates too far from 60 Hz. That happens once every 2 months or so. The idea is to protect my home's electrical system from dirty power.