Non-metals in general are poor conductors of electricity.
The elements generally regarded as nonmetals are:
hydrogen (H)
In Group 14: carbon (C)
In Group 15: nitrogen (N), phosphorus (P)
Several elements in Group 16, the chalcogens: oxygen (O), sulfur (S), selenium (Se)
All elements in Group 17 - the halogens
All elements in Group 18 - the noble gases
Phosphorus, sulphur and chlorine are poor conductors as " the outer electrons are not free to move and carry charge because they are held strongly in covalent bonds."