Why does Residual Current Device (RCD) trip with an electric hot plate?
Can this behavior be explained?


The hotplate is faulty and leaking more than 30 mA of current to earth (ground). This is dangerous. This is what RCDs and GFCIs are designed to protect you against.

Your RCD is attempting to save your life.


  For currents above 10 milliamps, muscular contractions are so strong that the victim cannot let go of the wire that is shocking him. At values as low as 20 milliamps, breathing becomes labored, finally ceasing completely even at values below 75 milliamps. 


Ohio State University


  Are there any errors in this situation to be corrected?


There's an error in the design, construction or operation of your hotplate. There's nothing to suggest your electrical installation is faulty.

You could report the faulty hotplate to your local equivalent of "trading standards". It is illegal to sell goods that don't comply with electrical regulations.

You could return the hotplate to the seller for a refund.