5kV Insulation Tester — When You Need the Full Diagnostic Voltage

Why 5 kV Is the MV Standard

IEEE 43 specifies test voltage at twice the equipment rated voltage plus 1000 V. For 11 kV cables that is 23 kV in factory acceptance, but for in-service maintenance 5 kV is the practical compromise — high enough to stress aging insulation, low enough to be safely portable. A real 5kV insulation tester like the EK-C350 is the right tool for substation, MV motor, and switchgear maintenance.

1. Three Tests That Need 5 kV

• Step-voltage test: apply 1 / 2 / 3 / 4 / 5 kV in sequence; resistance should be constant. A drop reveals weak spots.
• PI on MV motors: 1 kV is too low to polarise thick groundwall insulation.
• Cable acceptance: XLPE 6.6 kV cables need 5 kV PI / DAR.

2. Output Stability — The Hidden Spec

Cheap testers drop to 2 - 3 kV under load. The EK-C350 holds 5000 V regulated to ± 5 % up to 5 GΩ load — confirmed on the calibration certificate.

3. Built-in PI / DAR Timer

The EK-C350 auto-triggers 30 s, 60 s, 1 min and 10 min timers, computes DAR and PI, and writes to internal memory.

4. Battery Life Under Test

Driving 5 kV at 3 mA short-circuit current takes 15 W. A 5 kV tester needs ≥ 7.4 V Li-ion / 3 Ah; the EK-C350 ships with two 18650 cells delivering 8 hours of continuous test.

5. Safety Features Mandatory at 5 kV

1. Voltage-present warning (live circuit detection > 30 V).
2. Auto-discharge to < 50 V in < 5 s after test.
3. Insulated test leads rated 10 kV CAT IV.
4. Lockable test button (no accidental energisation).

The EK-C350 5kV insulation tester implements all five — request a demo through EK service teams before specifying for your substation fleet.