Answer.
Charged spheres attract each other when: They are oppositely charged
Step-by-step explanation
Like charges do not attract to one another, rather they repeal. However, recent research in physics and mathematics has shown the opposite in that at particular distances two spheres that have similar charge can possibly attract each other. Using the method of image technique to solve this problem, equal charges may attract only possible if the force of gravity between the two charged bodies is way more than the electrostatic force of repulsion. This is to mean that equal charged spheres may attract if charge by mass ratio of the bodies charged is tending to zero.