Do you have receptacles with reverse polarity in your home?
The majority of receptacles we use in a home today are designed with one slot larger than the other and a space below these two slots where the ground pin can go in. As a result, two (2) prong polarized plugs and three (3) prong plugs then can only be inserted to into them in one particular way. The wider slot on the left side (above the space for the ground) is the side of the receptacle that the white neutral wire is attached to, while the smaller slot on the right side of the receptacle is where the black hot wire is attached. When wired correctly it reduces the potential shock hazard.
Shocks from appliances, scorched receptacles / plugs or an appliance that stops working prematurely are indicators that reverse polarity may be present.
The trouble is, when reverse polarity is present we often get a false sense of security as, for example, when we plug something into a receptacle with reverse polarity they seemingly work…at least initially. So, you need to physically test and or inspect that receptacle.
If you are unsure if your receptacles are wired properly, get them inspected.