What to Do If Your Wire or Cable Develops a Leakage Current?

A Professional Guide from a Cable Industry Manufacturer

Electricity is indispensable to both industrial production and daily life. While it brings great convenience, improper use or faulty wiring can lead to serious hazards. Today, we’ll walk through exactly what to do if you discover leakage current in your wires or cables.

Immediate action:​ Cut power and isolate risks first. Then follow the four-step process: Identify → Inspect → Repair → Protect. For concealed wiring, high-voltage systems, or if you are unsure, always call a licensed electrician.

I. Immediate Response (Life Safety First)

Cut Power Immediately:​

Turn off the main breaker or the faulty circuit’s air switch, and unplug any suspicious appliances. Never touch switches or wires with wet hands.

Isolate the Area:​

Stay away from the leakage point. Place dry wooden boards or insulating mats on the floor to prevent step-voltage electrocution.

Stop Using Equipment:​

All appliances on the affected circuit must remain offline until repairs are completed and the circuit passes safety testing.

II. Quick Identification: Circuit or Appliance?

Reset Test (RCD/GFCI):​

After a trip, press the reset button and reclose the breaker.

• Trips immediately again = Circuit leakage​

• Does not trip, but trips when a specific appliance is plugged in = That appliance is faulty

Segmented Power-Off Method:​

Unplug all appliances and turn off lighting switches → Close the breaker:

• Still trips = Circuit leakage​

• Does not trip → Plug in appliances one by one: whichever causes a trip is faulty.

Insulation Resistance Check (Multimeter / Megohmmeter):​

With power off, measure resistance between:

• Live / Neutral vs. Ground (or metal water pipe):

III. Common Causes of Leakage

• Insulation damage:​ Aging, crushing, bending, rodent bites, accidental drilling during renovation.

• Moisture ingress:​ Kitchen / bathroom / outdoor cables, poor sealing at joints or terminals.

• Joint failure:​ Loose connections, oxidation, poor contact, failed insulation tape.

• Overload / Overheating:​ Long-term overcurrent accelerating insulation aging.

• Poor grounding:​ Disconnected, corroded, or loose ground wires.

IV. Step-by-Step Troubleshooting (Easy → Difficult)

1. Visual Inspection (Power Off)

• Check visible cables:​ Cracks, blackening, burn marks, heat damage, unusual odors.

• Check sockets/switches:​ Water ingress, yellowing, oxidized copper parts, looseness.

• Check junction boxes/joints:​ Aged or fallen insulation tape, water inside.

• Check damp areas:​ Kitchens, bathrooms, basements, outdoor cable ends.

2. Segment Localization

• By circuit:​ Turn off branch breakers one by one; when RCD stops tripping = that circuit is faulty.

• By section:​ Disconnect at junction boxes or sockets; when disconnecting a section restores normal operation = that segment is faulty.

• Focus on:​ Wall penetrations, conduit ends, bends, joints, and old wiring (≥ 10 years).

V. Repair Methods (Safety Standards)

1. Minor Damage (No Copper Exposed)

Power off → Clean and dry → Wrap with insulation tape using 50% overlap for 5–8 layers​ → Cover with insulating sleeve or fiberglass tube.

2. Exposed Copper / Joint Leakage

Cut out damaged section → Re-strip → Twist or crimp securely → Seal with heat shrink tubing or waterproof insulation tape → Restore routing.

Joints must be suspended, not touching metal boxes or walls. Use waterproof junction boxes in damp areas.

3. Moisture-Related Leakage

• Minor:​ Unwrap ends, air-dry for 24–48 hours or use a low-heat dryer → Reseal.

• Severe:​ Cut out water-affected section, refit waterproof joints, or replace the entire segment.

4. Serious Aging / Multiple Damage Points

Replace the entire cable run; avoid local splicing. For old circuits (≥ 15 years), consider full rewiring.

VI. Verification & Long-Term Protection

Post-Repair Testing

• No-load closing:​ RCD does not trip.

• Insulation resistance:​ Restored to ≥ 0.5 MΩ.

• Load test:​ Switch on appliances one by one — no tripping, no abnormal heating.

Long-Term Protection Measures

• Install RCD/ELCB with ≤ 30 mA trip current and ≤ 0.1 s trip time.

• Use waterproof sockets + waterproof junction boxes in wet areas.

• Run wires through PVC flame-retardant conduits; keep joints accessible (do not bury).

• Schedule regular inspections: Test insulation yearly in older buildings; replace wiring after 10–15 years.

VII. Safety Red Lines (Strictly Prohibited)

Working live, repairing with wet hands, or using ordinary tape on high-voltage or severely damaged cables.

Removing or bypassing RCD/GFCI, or leaving ground wires disconnected.

Blindly breaking walls for concealed wiring damage — always have an electrician locate faults first.

Conclusion

Leakage current is never a minor issue.

Cut power first. Inspect carefully. Repair to standard. Protect for the long term.​

When in doubt, stop using the circuit immediately and call a licensed electrician.

Provided by Minfeng Cable, a direct factory and one-stop solution provider for the wire and cable industry.