# Insulation Resistance Calculation

I am trying to calculate the minimum insulation resistance of two parts (a capacitor and box) that are approximately 0.38mm apart or 0.00038m.

I've tried looking at resistivity of air which some people are giving as 1.3 × 10^16 per meter.

Would the equation 1.3x10^16 x 0.00038 = insulation resistance be accurate?

I am guessing no as I imagine the voltage applied and cross sectional area would also have an impact. I need the insulation resistance to be at least 50MOhms @ 50VDC.

• I don't think you will get reliable results with calculation. Measuring would be my choice. 50 VDC seems a bit low for insulation resistance. And can you make sure the distance stays the same and the humidity of the air? Maybe a solid insulator material would be a better choice with just 0.38 mm space. Jul 11, 2017 at 9:52
• Thank you for the reply. The distance will be the worst case scenario. As for the humidity they are assembled in a controlled environment but imagine there will be small differences. 50VDC is per the customer specification. This is not a high voltage so instincts tells me the gap will be okay but i would like to be sure. I've roughly estimated the crosssectional area to roughly 1.5mm x 1.5mm. Jul 11, 2017 at 10:28