VSD trips on earth/ground fault
The drive trips with an earth/ground-fault code — typically the instant it outputs — indicating leakage to earth on the motor or output cabling.
Safety first
An earth-fault trip can indicate damaged insulation and a shock risk. Isolate, discharge the bus, and prove dead before testing output cabling. Don't reset repeatedly into an earth fault.
Isolate, lock out / tag out, and prove dead before working unless a live test is specifically required, authorised, and carried out under proper supervision. Always follow local regulations, your site procedures, and the equipment manufacturer's documentation.
Full detail — causes, the why, and common mistakes.
Likely causes
Ranked from most to least likely.
Premium fault tree
The full ranked causes, test sequence and flowchart for this fault are part of Sparkie Sidekick Pro.
Coming soon — no payment required during preview.
Testing sequence
Work through one test at a time. Expected reading and what each result means.
Full test sequence
The step-by-step test flow with expected readings for this fault is part of Sparkie Sidekick Pro.
Coming soon — no payment required during preview.
Fault-finding flowchart
The same logic as a decision tree.
- 1start
VSD earth-fault trip
→ step 2 - 2decision
Is motor + cable insulation to earth healthy?
Yes→ step 3No→ step 4 - 3decision
Are terminations dry and clean?
Yes→ step 5No→ step 6 - 4result
Low insulation — locate and repair the leakage.
- 5decision
Is output cable length within the drive's allowance?
Yes→ step 7No→ step 8 - 6result
Dry/clean and reseal the terminations.
- 7result
Refer to drive docs on earth-fault detection.
- 8result
Excessive length/capacitance — apply long-cable measures.
Common mistakes apprentices make
- Resetting repeatedly into an earth fault instead of isolating and testing.
- Testing with everything connected and not isolating motor vs cable.
- Overlooking moisture in the motor terminal box.
- Ignoring very long output cables as a cause.
When to stop & escalate
A confirmed insulation fault is a repair (motor or cable) — don't run until fixed. Long-cable mitigation (output filters/reactors) is a design consideration to plan properly.
If you're past your competence, authorisation, or the safe limits of the job — stop and hand it on. There's no fault worth getting hurt over.
Related faults
VSD trips on overcurrent / overload
The drive trips with an overcurrent or overload code — on start, on acceleration, or under running load. It may restart and trip again on the same point in the cycle.
Motor with low insulation resistance to earth
An insulation resistance test on the motor reads low to earth — a sign the winding insulation is degraded, damp, or contaminated, risking trips and failure.
RCD / RCBO keeps tripping
An RCD or RCBO trips repeatedly — immediately on reset, randomly during the day, or only when certain equipment runs. The earth-leakage protection is doing its job; something is leaking.
Learn the theory
How the gear and circuits behind this fault actually work.