Electrical – 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 1.3×10^16 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.

Could you please advise.

Thank you in advance.

Best Answer

In electrical engineering we are more normally concerned about the breakdown strengths of air gaps, not the resistance of air.

But since you are trying to validate that you are meeting a customer's specification, however unusual, you can use the calculation you propose. I would recommend, however, that you ask your customer to agree with your assessment methodology. Due to the unusual specification, they may have something else in mind.