What a hipot test proves
“Dielectric withstand,” “high potential” and “hipot” all name the same safety test: a high voltage is applied across the DUT’s insulation and the instrument watches for breakdown or flashover (arcing). It is the final check that catches inadequate clearance, damaged insulation and contamination before a product ships, and high-voltage relays do the switching inside the tester.
What a safety compliance tester contains
A modern compliance tester combines AC and DC withstand testing, typically up to 5 kV AC / 30 mA and 6 kV DC / 15 mA, for electronic equipment, components and insulating materials. Most also include a multi-channel scanner that routes the hipot source to each test point in turn, and that scanner is where the high-voltage relays sit.
What the relay has to guarantee
- Withstand above the test voltage. On a 5 kV AC output the relay has to hold off with margin, or it arcs internally and creates a false failure.
- Very high insulation resistance so relay leakage does not add to the DUT’s measured leakage.
- Long creepage and clearance to survive repeated HV switching without surface tracking.
- Fast, repeatable operation to keep multi-point scan cycles short.
- Long electrical life for production test that runs continuously.
HVR series figures
The HVR high-voltage reed relay is offered in 4/5/6/10/15/20 kV withstand versions.
- Contact switching voltage to 10 kVDC; dielectric (breakdown) withstand to 20 kV
- 3 A switching current; 5 A maximum carrying current
- Pulse current options 5 A / 10 A / 20 A
- Insulation resistance 10 TΩ and above
- Multiple contact forms; PCB through-hole or high-voltage lead-wire mounting
- Operate time 3 ms, release time 1.5 ms
The body is epoxy-encapsulated, with insulation resistance of 1012 Ω and creepage distance greater than 32 mm, covering the AC source, DC source and the scan matrix that distributes either one across the DUT.
Why relay leakage decides the verdict
The point worth stressing is that a hipot tester judges pass/fail partly from the leakage current through the DUT. If the switching relay itself leaks, that current is added to the reading: a good device can be rejected, or a marginal device can look clean. A relay in the 10 TΩ range puts the switch’s own leakage many orders of magnitude below the DUT’s, so the verdict reflects the device under test rather than the instrument. The same logic sets the withstand margin — the relay must never be the component that breaks down during a breakdown test.
About SHR AUTOSENSOR
SHR AUTOSENSOR TECH LIMITED (SHR AUTOSENSOR) manufactures high-voltage reed relays, mercury wetted relays and high-voltage DC contactors. Contact: [email protected] | +86 13761571029 | www.reed-relay.com