Why did POWEReasy trip?
During startup the POWEReasy device has identified that the sequence of supply phases has been interchanged. If this site is not a new installation then this has occured from the supplier directly. This reversal of phases is causes the motors to operate in reverse direction leading to unwanted process outcomes and in many cases failures of motors. POWEReasy has disconnected the supply to prevent both of these unwanted outcomes.
What could be the root cause of the phase reversal fault?
Phase reversal is caused due to faulty interconnections from the electricity supplier.
Can you use electricity under some precautions? What are these?
If the site has three phase motor loads, then you can temporarily interchanging the input connections between Y and B phases as well as the output Y and B phase wires. If the site does not have any three phase motors it is safe to use the supply as by interchanging the input Y and B phase wires.