What is Hi-Pot Testing?

Hi-pot (high potential) testing, also called dielectric withstand testing, applies a high voltage between conductors and between conductors and ground to verify the integrity of electrical insulation. It is the most important electrical safety test performed on power cords during production, designed to detect insulation defects that could lead to electric shock, short circuits, or fire hazards. Zhejiang Jinting Nuclear Cable Co., Ltd. performs 100% hi-pot testing on every power cord manufactured.

Test Voltage Levels

Cord Rating	Typical DC Test Voltage	Typical AC Test Voltage
125V cords	1500-2000V DC	1000-1500V AC
250V cords	2000-2500V DC	1500-2000V AC
300/500V cables	2500-3000V DC	2000V AC
450/750V cables	3000-4000V DC	2500V AC

Test Procedure

The hi-pot test is performed on the fully assembled cord set after all manufacturing operations are complete. The test connects the high-voltage source between: all live conductors connected together and the ground conductor (for 3-wire cords), all live conductors connected together and an external conductive wrap or water bath surrounding the cord, and between each individual conductor and the other conductors connected together. The voltage is ramped up to the test level, held for the specified duration (typically 1-60 seconds depending on the test standard), and the leakage current is monitored. The cord passes if no breakdown occurs and the leakage current remains below the acceptance limit.

AC vs. DC Hi-Pot Testing

Both AC and DC hi-pot tests are used in power cord manufacturing. AC testing applies a sinusoidal voltage and measures resistive and capacitive leakage current combined, and is generally considered more representative of operating conditions. DC testing applies a constant voltage with no capacitive current, making it easier to set clear pass/fail leakage limits, and does not stress the cable’s capacitance. DC testing is more commonly used in production environments because the equipment is simpler and the acceptance criteria are more straightforward. Zhejiang Jinting Nuclear Cable Co., Ltd. uses both methods as appropriate for different product types and certification requirements.

Common Failure Modes Detected

Hi-pot testing can detect insulation defects caused by conductor strands piercing through insulation during assembly, insufficient insulation thickness, contamination or moisture in the insulation, damaged or cut insulation during stripping or handling, poor molding causing conductor proximity or movement, and aging or degradation of insulation materials. These defects, if undetected, could lead to shock hazards, short circuits, electrical fires, or premature cable failure.

Production Testing at Jinting

Our automated hi-pot test systems test every cord on the production line. High-speed automated fixtures make rapid connections to plug and connector pins. Multiple test points are verified simultaneously. Pass/fail results are logged with serial number traceability. Failed cords are immediately removed from the production stream for analysis, and batch test data is reviewed for trends that might indicate process drift. This 100% testing regime, combined with our sampling tests and certifications, ensures that every power cord from Zhejiang Jinting Nuclear Cable Co., Ltd. meets the highest safety standards.