Question

why are covalent compounds good conductors of electricity

Answer 1

Covalent compounds do not conduct electricity.
This means that the covalent compounds are non-electrolytes. Covalent compounds do not conduct electricity because they do not contain ions.
Foe example:
Covalent compounds like Glucose , alcohol etc do not conduct electricity because they do not contain ions.

Answer 2

Covalent compounds are not good conductor of electricity because they don't have a free electron. They doesn't have ions, so they are poor conductor of electricity.