I came across a tweet recently:
Don’t even THINK about using a 2-prong plug in a 3-hole slot! Use
only the required number of slots in an outlet or power strip.
Below was a picture of a burned-out grounded extension cord.
I'm hesitant to argue with anyone in the business of keeping our food, shelter, clothing and loved ones from combining with oxygen, but this seemed quite strange; I can't think of any possible way this could be a fire hazard.
The NEMA 5-15 wall receptacles in Canada are grounded by default, for reference.
Best Answer
The Fire Dept is wrong - it is perfectly normal to plug a device with a 2-pin plug into a 3-hole socket.
Breaking the ground pin off a 3-pin plug, then plugging that into a 2-hole or 3-hole socket may produce an electrical hazard - possibility of a shock.
If a high-current load, like an electric heater, was plugged into that burned outlet, and the contacts made poor contact, that would cause the overheating and resulting fire, whether the heater had a 2 or 3 pin plug.