Insulation Resistance

Try this : http://www.sengpielaudio.com/calculator-ohm.htm

or here : http://www.usbr.gov/power/data/fist/fist3_1/vol3-1.pdf

Or to say it another way, I think you already know the answer to this question. The problem is that you may not have thought about it enough before you asked it.

Let me answer your question with a few of my own.

First, is there more than one type of insulation?

Do each of the insulator types have different characteristics?

Is it reasonable to expect one formula to cover every situation? Of course not. There will be some factors that vary for possible insulator.

Lastly, is the world flat?

But, every insulator have specific insulation resistance at specific temperature.

Here I am asking that for definite voltage level is there any definite insulation resistance to allow limited leakage current.Is there any standards for limited Leakage current for different level of voltages.

Contact manufacturer

1. Every insulator has maximum allowable threshold breakdown electric field [V/mm] (Volts/thickness of insulator). Above this limit breakdown may occur, destroying insulator (lowering alowable voltage, or forming shortage).

2. Below this limit, leakage currents usually exist. Sufrace leakage currents depend very much on humidity (may change several orders of magnitude). Allowable leakage depends on application.