AdvancedHigh risk

Faint tingle or voltage on an appliance frame

A user reports a faint tingle off a stainless appliance, tap, or metal enclosure. A meter shows some voltage between the frame and true earth, but the RCD hasn't tripped.

Start fault-finding Log readingsEnter Job Mode

Safety first

Touch voltage on metalwork is a serious shock hazard — treat it as dangerous and stop people using the equipment. Do not rely on 'it's only a tingle'. Isolate and investigate the earth path before anyone touches it again.

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.

Apprentice mode

Full walk-through — the why, what readings mean, mistakes & safety.

Likely causes

Ranked from most to least likely.

  1. 1

    Lost or high-resistance protective earth

    Most likely

    If the earth to the frame is broken or high-resistance, normal leakage current can't drain away and lifts the frame to a touch voltage without drawing enough to trip protection.

  2. 2

    Accumulated leakage from electronics/filters

    #2

    EMC filters in many appliances leak a small current to the frame. With a poor earth, that leakage shows up as a touch voltage you can feel.

  3. 3

    Partial insulation breakdown inside the appliance

    #3

    A winding or element starting to break down to the frame puts voltage on the metalwork — a developing internal fault.

  4. 4

    Lost neutral raising local earth/MEN reference

    Least likely

    A neutral problem on the installation can shift earth references and energise metalwork — a wider and more dangerous fault than a single appliance.

Reports are saved on this device to reflect what you actually find.

Testing sequence

Work through one test at a time. Expected reading and what each result means.

On the tools? Job Mode shows one test at a time with thumb-sized buttons — your place and readings carry straight over.

Enter Job Mode
Test 1 of 3
1

Stop using the equipment. Safely isolate, then test continuity of the protective earth from the frame back to the main earth.

Expected reading

A low-resistance, solid earth connection to the frame.

If it passes

Earth path is intact — focus on insulation breakdown or wider neutral/earthing issues.

If it fails

A broken/high-resistance earth explains the touch voltage — repair the earth path before re-energising.

Often leads toHigh earth-fault loop impedance / earthing concernLost or high-resistance neutral
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View all expected readings at once
1. Stop using the equipment. Safely isolate, then test continuity of the protective earth from the frame back to the main earth.
A low-resistance, solid earth connection to the frame.
2. With the appliance isolated and unplugged, insulation-resistance test active/neutral to the frame.
High insulation resistance between live parts and the frame.
3. Check neutral-to-earth at a nearby point and confirm the installation's main earthing/neutral is healthy.
Neutral-to-earth near zero and main earthing intact.

Fault-finding flowchart

The same logic as a decision tree.

  1. 1
    start

    Tingle / voltage on appliance frame

    → step 2
  2. 2
    decision

    Is the protective earth to the frame solid and low-resistance?

    Yes→ step 3No→ step 4
  3. 3
    decision

    Is insulation resistance live-parts-to-frame high?

    Yes→ step 5No→ step 6
  4. 4
    result

    Broken / high-resistance earth — repair the earth path before re-energising.

  5. 5
    decision

    Is neutral-to-earth near zero and main earthing healthy?

    Yes→ step 7No→ step 8
  6. 6
    result

    Internal insulation breakdown — remove the appliance from service.

  7. 7
    result

    Local leakage with a marginal earth — confirm earthing and bonding.

  8. 8
    result

    Installation neutral/earthing fault — escalate urgently, keep equipment out of use.

Common mistakes apprentices make

  • Telling the customer the tingle is harmless and leaving the equipment in use.
  • Chasing the appliance when the real fault is a broken protective earth.
  • Not checking whether a lost neutral is energising metalwork more widely.
  • Re-energising before the earth path is proven solid.

When to stop & escalate

Touch voltage on metalwork combined with a neutral or main-earthing problem is a whole-of-installation hazard — escalate immediately and keep the equipment out of use. Stop if the fault extends beyond a single appliance.

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.

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