IEC 60950-1 was formally withdrawn in 2020, yet many product teams still apply its formula-based voltages without confirming which hipot test IEC standard now governs their design.
The applicable standard is determined by product category, not by mains voltage class. Selecting the wrong one invalidates certification evidence at the test house.
Three IEC standards cover most of the electronic products market: IEC 62368-1 for audio, video, IT, and communications equipment; IEC 60335-1 for household appliances; and IEC 61010-1 for measurement and laboratory instruments.
This article maps product type to applicable standard, specifies the exact test voltages and durations each requires, and draws the routine vs. type test boundary that governs production-line testing.
Part 1 — What a hipot test verifies · Part 2 — How to perform a hipot test · Part 3 — How to prevent hipot test failures
Which IEC Standard Applies to Your Product Type?
The selection starts with product function. Each IEC standard defines a scope, and the product’s primary function determines which scope governs, regardless of circuit topology.
If the product plays, processes, stores, or transmits audio, video, or data for consumer or professional use, the applicable standard is IEC 62368-1.
When the product heats, moves, illuminates, or performs a domestic function, IEC 60335-1 governs. If it measures, monitors, or controls a process in a laboratory or industrial setting, IEC 61010-1 applies.
Medical electrical equipment falls under IEC 60601-1, which sets materially higher isolation test voltages for applied parts connected to patients. IEC 60601-1 is outside the scope of this article.
When a product straddles two scopes, the standard matching the product’s primary function and declared intended use takes precedence. Confirm scope selection with the relevant accreditation body before certification begins.
What Does IEC 62368-1 Require for the Dielectric Withstand Test?
IEC 62368-1 specifies dielectric strength requirements in Clause 5.4. Unlike IEC 60950-1, which used the formula 2U + 1000 V, IEC 62368-1 uses Table 15, keyed to insulation type and peak working voltage.
For a 230 V AC mains supply, the peak working voltage is approximately 325 V. Table 15 specifies approximately 1500 V AC for basic insulation at this working voltage.
For reinforced or double insulation at the same working voltage, approximately 3000 V AC applies.
The type test runs at full voltage for 60 seconds. The routine test, conducted on every production unit, applies the same voltage for 1 second.
Verify the specific routine test clause before specifying production parameters, as sub-clause provisions vary between the second and third editions.
The 3-part hipot testing series on this site covers the fundamentals of hipot testing, how to execute the test correctly, and how to design for compliance from the outset.
This article addresses which standard governs the test and what voltages it requires.
Insulation classification under IEC 62368-1
IEC 62368-1 classifies insulation as basic, supplementary, reinforced, or double. Each type carries a distinct Table 15 test voltage.
Basic insulation provides a single level of protection against electric shock. Supplementary insulation is an independent second layer applied above basic insulation.
Double insulation combines basic and supplementary. Reinforced insulation is a single construction that provides equivalent protection to double insulation.
The test voltage for reinforced insulation is approximately double the basic insulation value at the same working voltage.
This follows directly from the classification: reinforced insulation must withstand the same dielectric stress that two separate layers would together absorb.
How Does IEC 60335-1 Specify the Hipot Test for Household Appliances?
IEC 60335-1 Clause 16.3 covers dielectric strength. The test voltage is set by table, not by formula: for basic insulation at a working voltage up to 250 V, the value is 1250 V AC. For reinforced insulation under the same conditions, the value is 3000 V AC (Clause 16.3, Table 7 in current editions).
Higher working voltages scale to higher table values. For working voltages above 250 V or for products with internal voltage conversion, derive the test voltage from the applicable Table 7 row using the actual working voltage at each insulation barrier.
The type test duration is 1 minute. For routine production testing, IEC 60335-1 Annex A permits an alternative of 5 seconds at the same test voltage, conducted with the appliance held at operating temperature.
The legacy 2U + 1000 V formula is not part of IEC 60335-1. That formula belongs to the withdrawn IEC 60950-1 standard for IT equipment and should not be applied to household appliance certification.
What Are the IEC 61010-1 Hipot Requirements for Measurement and Lab Equipment?
IEC 61010-1 Clause 6.8 specifies electric strength tests using Table 6. The table maps working voltage and Overvoltage Category (CAT I through CAT IV) to a required test voltage.
The Overvoltage Category reflects the transient overvoltage environment the equipment is designed to withstand.
For basic insulation at 250 V working voltage under Overvoltage Category II, Table 6 specifies 1500 V AC. For reinforced insulation at the same rating, the value is 3000 V AC.
CAT III and CAT IV applications carry higher Table 6 values. Determine the correct Overvoltage Category for the intended installation environment before selecting the test voltage.
Applying CAT II values to a CAT III installation is a common error that survives into certification documentation.
IEC 61010-1 also requires humidity pre-conditioning before Clause 6.8 tests when the equipment is rated for use above a defined relative humidity level.
This pre-conditioning requirement does not apply to IEC 62368-1 or IEC 60335-1 dielectric strength tests conducted under standard laboratory conditions.
How Did Hipot Test Voltages Change From IEC 60950-1 to IEC 62368-1?
IEC 60950-1 Clause 5.2.2 derived the type test voltage for basic insulation using the formula 2U + 1000 V, where U is the rated mains voltage. For a 230 V supply, the result is 1460 V, applied for 60 seconds.
IEC 62368-1 does not use a formula. It uses Table 15, keyed to peak working voltage and insulation type.
For a 230 V AC supply with a peak of approximately 325 V, the Table 15 voltage for basic insulation aligns closely with the IEC 60950-1 result.
In practice, the type test voltage for basic insulation at mains level is broadly comparable between the two standards. The critical difference is in how working voltage is determined for circuits involving voltage conversion.
IEC 62368-1 requires identifying the actual peak working voltage at each insulation barrier, not applying the rated supply voltage.
A rectified 230 V mains supply carries a DC link voltage above 300 V. This raises the applicable Table 15 row and can increase the required test voltage at secondary-side barriers.
The more significant transition impact for most teams is insulation classification, not test voltage magnitude. IEC 60950-1 used a construction-based model with defined insulation layer counts.
IEC 62368-1 uses a hazard-based energy source classification. Reclassifying a design can change insulation requirements at specific barriers even when supply voltage is unchanged, shifting the applicable Table 15 voltage.
Teams transitioning from IEC 60950-1 should re-derive test voltages from IEC 62368-1 Table 15 for each barrier rather than carrying forward old values. The IEC 62368-1 transition overview covers the full reclassification methodology.
What Is the Difference Between a Routine Test and a Type Test in IEC Hipot Standards?
The type test is conducted once during product certification, at an accredited laboratory, to demonstrate that the design meets the insulation requirements of the applicable standard.
The routine test is conducted on every unit during production to confirm that the manufacturing process has not introduced insulation defects. It is a quality gate, not a certification test.
The duration distinction varies by standard. IEC 62368-1 routine tests apply the same voltage as type tests for 1 second. IEC 60335-1 permits a 5-second routine test at the type-test voltage, with the appliance at operating temperature.
Some manufacturers apply 120% of the type test voltage for a shorter duration as a margin screen. This must be explicitly supported by the applicable standard clause and documented in the production control plan before implementation.
Routine test failures that do not occur during type testing indicate a manufacturing process issue: solder bridges, wire pinching, incorrect insulation placement, or contamination.
A systematic increase in routine test fail rate is a process quality signal, not a design signal.
When Can You Substitute DC for AC in a Hipot Test Under IEC Standards?
IEC 62368-1, IEC 60335-1, and IEC 61010-1 all permit a DC test voltage as an alternative to AC. The equivalent DC voltage is √2 times the specified AC test voltage, reflecting the peak-to-RMS ratio.
For a basic insulation test at 1500 V AC, the DC equivalent is approximately 2121 V. For a reinforced insulation test at 3000 V AC, the equivalent is approximately 4243 V.
DC testing eliminates capacitive charging current, which removes nuisance trips on EMC-filtered power supplies.
Fault location is also more straightforward: the fault current profile at breakdown is distinct from the capacitive baseline.
The limitation of DC testing is that it does not stress insulation in both polarities. AC applies positive and negative peaks in every cycle, revealing certain dielectric defects that DC would not expose.
Where a standard permits DC, document the choice and the rationale in the test plan.
For high-capacitance products, use a DC test set capable of applying the correct √2 voltage. Confirm with the test house that DC substitution is permitted for the specific insulation under test.
Record the substitution explicitly in the production test specification.
The Electrical Safety Compliance Guide provides wider context on insulation coordination and production test requirements across the major IEC product safety standards.
Frequently Asked Questions
Which IEC standard applies to the hipot test for IT and computer equipment?
IEC 62368-1, which replaced IEC 60950-1 in most major markets by the end of 2020. Products certified under IEC 60950-1 must recertify under IEC 62368-1 when the certification is renewed or the design is modified. Test voltages come from Table 15, not the legacy 2U + 1000 V formula.
What voltage does IEC 62368-1 require for the hipot test at mains voltage?
For basic insulation at a peak working voltage of approximately 325 V, derived from a 230 V AC supply, Table 15 specifies approximately 1500 V AC. For reinforced or double insulation, approximately 3000 V AC.
What is the difference between IEC 60950-1 and IEC 62368-1 for hipot testing?
IEC 60950-1 used the formula 2U + 1000 V to determine the test voltage for basic insulation. IEC 62368-1 uses Table 15, based on peak working voltage and insulation type. Voltage magnitudes are comparable for simple mains-to-secondary barriers, but IEC 62368-1 requires working voltage to be determined at each barrier, which can change requirements for internally converted voltages.
Can I use a DC hipot tester instead of AC under IEC standards?
Yes, subject to conditions. IEC 62368-1, IEC 60335-1, and IEC 61010-1 all permit DC as a substitute for AC, with the DC voltage set to √2 times the specified AC value. DC reduces nuisance capacitive trip currents but does not stress insulation in both polarities. Document the DC substitution and its rationale in the test plan and confirm with the test house before use.
What is the difference between a routine hipot test and a type test?
The type test is a certification test conducted once on a design sample. The routine test is a production quality gate on every manufactured unit. Both apply the type-test voltage; the duration varies by standard (1 second under IEC 62368-1, 5 seconds under IEC 60335-1 Annex A).
Conclusion
Product type determines the applicable hipot test IEC standard: IEC 62368-1 for audio, video, IT, and communications equipment; IEC 60335-1 for household appliances; IEC 61010-1 for measurement and laboratory instruments.
IEC 62368-1 Table 15 replaces the IEC 60950-1 formula, and teams transitioning from legacy designs must re-derive test voltages at each insulation barrier from the peak working voltage, not from the rated supply voltage.
The type test and routine test use the same voltage; duration alone separates certification evidence from production quality control, and that duration varies by standard.
IEC 62368-1:2023 is gaining adoption in major markets; verify whether Table 15 values or clause structure have been revised before beginning any new certification programme.
