Why Does Your Low Voltage Switchgear Keep Tripping?

Why Does Your LV Switchgear Keep Tripping?
7 Common Causes and Solutions 

Introduction

Tripping is one of the most common faults in low voltage switchgear. For many customers in Africa, frequent tripping not only disrupts production but also leaves them confused – is it a quality problem? A sizing issue? Or an operational mistake?

The truth is, different types of tripping point to different problems.

This article summarizes 7 of the most common causes and provides how to identify each one and how to fix it. Follow these steps to quickly troubleshoot and reduce downtime.

1️⃣ Cause 1: Overload – The Most Common Cause of Tripping

Problem description:
The actual current in the circuit exceeds the circuit breaker's rated current. This often happens when more equipment is added over time without upgrading the switchgear.

How to tell:

• Tripping occurs when all equipment is running

• The circuit breaker feels hot to the touch after tripping

• A clamp meter shows current exceeding the breaker rating

Solutions:

• Short term: Reduce the number of devices running at the same time

• Medium term: Replace with a higher-rated breaker (must confirm cable size matches)

• Long term: Recalculate the load and add more distribution circuits or upgrade the panel

✅ Advice for African markets: Many factories add equipment gradually. We recommend leaving 20–30% spare capacity when selecting switchgear.

2️⃣ Cause 2: Short Circuit – The Most Dangerous Cause

Problem description:
A live wire touches another live wire or the ground, creating a huge current that causes the breaker to trip instantly.

How to tell:

• Very fast trip, often with a "bang" sound or spark

• Breaker handle usually moves to the middle "tripped" position

• If you reset and turn it on, it trips again immediately

Solutions:

• Disconnect all loads and try to reset the breaker

• If it holds → the problem is on the load side (check equipment, cables, sockets)

• If it still trips → the problem is in the wiring or inside the panel (call an electrician)

⚠️ Safety warning: Do not keep forcing a breaker back on after a short circuit trip. Find the fault first.

3️⃣ Cause 3: Earth Leakage – An Often Overlooked Cause

Problem description:
A breaker with earth leakage protection detects current leaking from the live wire to ground (usually above 30mA) and trips.

How to tell:

• The breaker has a "Test" button or leakage symbol

• Trips often happen in wet conditions (rainy days, water pumps, outdoor equipment)

Solutions:

• Check if any equipment has gotten wet

• Check for damaged cable insulation

• Temporarily disconnect suspected equipment one by one to isolate the problem

✅ Advice for African markets: In humid areas (coastal regions, long rainy seasons), we recommend adding earth leakage protection for outdoor circuits.

4️⃣ Cause 4: Aging Components – Equipment Has Been in Service Too Long

Problem description:
Circuit breakers, contactors, thermal relays, and other components have been in use for many years. Internal contacts oxidize, mechanisms become stiff, and bimetal strips lose accuracy.

How to tell:

• Switchgear has been running for 8–10 years or more

• Tripping becomes more frequent even though the load has not increased

• Breaker handle feels rough or stiff when operated

Solutions:

• Replace aging breakers or contactors

• Gradually replace components on critical circuits

✅ Advice for African markets: Keep spare breakers of common sizes, especially for the main incoming and critical circuits.

5️⃣ Cause 5: Loose Connections – The Most Easily Overlooked Cause

Problem description:
Screw terminals on breakers or contactors have loosened over time. This increases contact resistance, causing heat buildup and eventual thermal tripping.

How to tell:

• Tripping is irregular – sometimes once a day, sometimes once a week

• An infrared thermometer shows terminals much hotter than surrounding areas

• Discoloration or burn marks near terminals

Solutions:

• Disconnect power and retighten all terminals with a screwdriver

• Inspect and retighten every 6–12 months

✅ Advice for African markets: In high-vibration environments (near generators, in factories), connections loosen faster – increase inspection frequency.

6️⃣ Cause 6: High Ambient Temperature – Poor Heat Dissipation

Problem description:
The switchgear is installed in a hot environment (rooftop, outdoors, near heat-generating equipment) or has poor ventilation. This reduces the breaker's capacity, causing it to trip below its rated current.

How to tell:

• Internal temperature of the panel is clearly above 40°C

• Load current is below the breaker rating, but it still trips

• Panel enclosure feels very hot to the touch

Solutions:

• Add cooling fans or air conditioning

• Ensure adequate space for ventilation in front of and behind the panel

• Do not place heat-generating equipment next to the switchgear

✅ Advice for African markets: Summer temperatures can be extremely high in some regions. Install switchgear in a shaded, well-ventilated location. If needed, choose breakers rated for high ambient temperatures.

7️⃣ Cause 7: Harmonic Distortion – The Hidden Killer in Modern Factories

Problem description:
Equipment such as VFDs, UPSs, and LED lighting generate harmonic currents. Harmonics can cause thermal tripping in breakers or nuisance tripping in earth leakage breakers.

How to tell:

• Load current is not high, but breakers frequently trip due to heating

• Earth leakage breakers trip for no apparent reason when equipment is running normally

• A power quality analyzer shows total harmonic distortion (THDi) above 30%

Solutions:

• Add line reactors or harmonic filters in front of harmonic-generating equipment

• Choose breakers designed for harmonic environments

• Group harmonic-generating equipment on a dedicated transformer

✅ Advice for African markets: As factories become more automated, harmonic problems will become more common. If you are unsure, contact us for power quality testing.

8️⃣ Quick Troubleshooting Flowchart

text

Tripping occurs
    │
    ▼
Was there a "bang" sound or spark?
    │
    ├── Yes → Short circuit → Disconnect loads, check equipment and cables
    │
    └── No → Continue
              │
              ▼
Does the breaker have a "Test" button (earth leakage)?
    │
    ├── Yes → Earth leakage → Check for wet equipment or damaged cable insulation
    │
    └── No → Continue
              │
              ▼
Use a clamp meter. Is current above the breaker rating?
    │
    ├── Yes → Overload → Reduce load or upgrade breaker
    │
    └── No → Continue
              │
              ▼
Use an infrared thermometer. Are terminals overheating?
    │
    ├── Yes → Loose connection → Disconnect power and retighten terminals
    │
    └── No → Continue
              │
              ▼
Is the internal panel temperature above 40°C?
    │
    ├── Yes → High ambient temperature → Add fans, improve ventilation
    │
    └── No → Continue
              │
              ▼
Has the equipment been running for more than 8 years?
    │
    ├── Yes → Aging components → Replace breakers or contactors
    │
    └── No → Possible harmonic issue → Consider power quality testing

Conclusion

Frequent tripping in low voltage switchgear is often not a quality problem – it is usually related to sizing, usage, or environmental conditions. By following the 7 causes and troubleshooting steps above, most problems can be quickly identified and solved.

Advice for customers:

1. Do not keep forcing a breaker back on after tripping – find the cause first

2. Inspect and retighten terminals every 6–12 months

3. Ensure proper ventilation around the switchgear

4. Keep spare breakers of common sizes for critical circuits

5. If you have VFDs, UPSs, or similar equipment, pay attention to harmonic issues

We supply complete low voltage switchgear panels and matching components. If you are experiencing tripping problems and cannot solve them yourself, please contact us. We can help with remote diagnosis or provide replacement solutions.

Contact us：
Web: https://yqsxdl.en.made-in-china.com/
Whatsapp：+86 195 1818 9858
Mail: lunahe927@gmail.com/19518189858@163.com