Insulation resistance & leakage calculator

Turn an insulation-resistance reading into the leakage current it allows: enter the megohms and test voltage, and read the leakage current plus a pass/fail check against common thresholds.

Readings

Insulation resistance

Reading from your megohmmeter

Test voltage

Megohmmeter test voltage (usually 250 or 500 VDC)

Acceptable threshold

IEC 60512-2-1 style guidance for many connectors and cables

Leakage current & verdict

Leakage current: 5.00µA
Verdict: PASS(R ≥ 100 MΩ)

Below ~1 MΩ usually indicates moisture or insulation damage — treat the part as unsafe to energise.

About insulation resistance

Insulation resistance is usually measured with a 250 or 500 VDC megohmmeter, and the reading is temperature- and humidity-dependent. A low reading after a damp period should be re-checked once the part has dried — a reading that stays low when dry points to real insulation damage.

Related parts

Browse related parts:

cable connectors heat-shrink

Frequently asked questions

How do you convert an insulation resistance reading into leakage current?

Leakage current follows I = V ÷ R: with the resistance in megohms and the test voltage in volts, dividing the two gives the leakage directly in microamps. With the defaults — 100 MΩ at 500 V — the leakage is 5 µA, and the part passes against the 100 MΩ threshold.

What insulation resistance is acceptable for a connector?

The tool compares the reading against an acceptance threshold you pick — 10, 50, 100 or 500 MΩ, or 1 GΩ — using IEC 60243 / 60227 style guidance common for connectors and cables. As a rule of thumb, a reading below about 1 MΩ suggests moisture or insulation damage.

Why use a 500 V megohmmeter test voltage?

Insulation resistance is usually measured with a 250 or 500 VDC megohmmeter, and the reading is temperature- and humidity-dependent. The calculator defaults to a 500 V test with a 100 MΩ threshold — a low reading after a damp period should be re-checked once the part dries.

How it works

Leakage current follows I = V ÷ R: with the resistance in megohms and the test voltage in volts, dividing the two gives the leakage current in microamps. The reading is then compared against the selected acceptance threshold — IC Source Direct uses the IEC 60243 / 60227 style guidance common for connectors and cables. As a rule of thumb, a reading below about 1 MΩ suggests moisture or insulation damage.

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IC Source Direct provides this tool for reference only.

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