Do you use multi-outlets?
Some multi-outlets are not grounded.
Leakage current also can flow to the refrigerator door if house wiring is not grounded.
How to fix
For housing wiring, contact an electrician for grounding.
When using a multi-outlet, use those with ground terminals.
Products with rated capacity over 15A should be used.
Outlets on walls are recommended for using refrigerators.
Plugging in many products into a multi-outlet can cause fire or electricity leakage.