# Preventing Electricity Leakage With Insulators

If we charge an object made of insulating material, the charges on it would leak to the medium as the time passes, due to the potential difference. I would like to know if there is a way to prevent leakage and conserve the charges on that object. I think, if we cover the object with an insulator which has higher volume resistivity than the insulator the object is made of, we would be able to make most of the charges stay in place. However, I am not sure if the charge flow is related with the electrical resistivity of materials. Is there a law which simply states that the charge flow could be prevented with good insulating although there is a potential difference? I know that the current in amperes is directly proportional to the conductivity of the material used in a circuit but would there be a way to create nearly no current at all?

• Do you mean that the insulator object has two disconnected surfaces and you place on one surface a charge, and on the other surface an opposite charge? – Sofia Jan 8 '15 at 2:32
• @Sofia I meant that let's say we have a charged object which is made of insulating material. How can we prevent charges to leak away? Would covering the object with better insulators make charges to stay in the object since insulators stop charge flow? – user57144 Jan 8 '15 at 9:18

• The current that flows depends on the electric field and the resistivity of the material. I assume you are familiar with Ohm's law - you can rewrite that in terms of electric field and bulk properties of the material. For a cylinder with area A, length $\ell$ you can write $V=IR$ or equivalently $\frac{E}{\ell} = \frac{I\rho\ell}{A}$ where $\rho$ is the resistivity. What I said above then follows. – Floris Jan 8 '15 at 18:05