Circuit breakers are essential devices in electrical systems that help protect equipment and prevent fires. However, they can malfunction over time and fail to trip when expected. Faulty circuit breakers in commercial buildings must be identified and corrected to maintain safety. Here is a comprehensive guide on troubleshooting issues with circuit breakers in commercial settings.
Safety Precautions When Working with Electrical Systems
It is crucial to follow safety protocols when troubleshooting circuit breakers to avoid electrocution and shock hazards:
- Wear insulated gloves and use insulated tools when working with electrical components.
- Turn off power to the circuit at the main breaker panel before testing.
- Use a non-contact voltage tester to confirm power is off before handling wires.
- Put up warning signs and barricade work areas to prevent accidental contact.
- Never work on electrical systems alone. Have someone ready to cut power or call for help if needed.
Adhering to electrical safety rules is vital to avoid severe injury or death when dealing with commercial electrical systems.
Understanding Circuit Breaker Operation
Circuit breakers function by interrupting the flow of electricity when unsafe conditions occur:
- They trip and switch open during an overload - when too much current flows through the circuit.
- They also trip due to a short circuit - when current takes an unintended path bypassing the load.
- In addition, they trip because of a ground fault - when some amount of current leaks through the grounding system.
Circuit breakers have a mechanism that heats up and bends when overcurrent occurs. This leads to the contacts separating and breaking the circuit.
Knowing the principles behind circuit breaker operation provides insight into potential failure points.
Signs of a Faulty Circuit Breaker
Several visible signs can indicate problems with circuit breakers:
- Frequent tripping - Breaker switches off regularly under normal loads.
- Failure to trip - Breaker does not trip even with major overloads or short circuits.
- Unusual noises - Buzzing, humming or cracking sounds coming from the breaker.
- Hot breaker - Breaker feels abnormally warm to touch.
- Burn/color changes - Discoloration or burn marks on the breaker.
- Corroded/damaged contacts - Visible corrosion or damage to connecting contacts.
Carefully observing circuit breaker issues and symptoms helps narrow down potential causes.
Common Causes of Circuit Breaker Failure
Faulty circuit breakers can result from various factors:
1. Overloading
- Running too many appliances on one circuit results in overloading over time.
- High inrush currents from motors, heaters and other equipment leads to frequent tripping.
- Overloading causes overheating and mechanical issues over time.
2. Moisture & Corrosion
- Exposure to moisture and water can corrode and damage internal components.
- Wet or damp installations such as basements can accelerate corrosion.
- Salt air and humidity in coastal areas also increases corrosion risk.
3. Age & Wear
- Circuit breaker contacts, springs and mechanisms degrade over time after repeated arcing.
- Old breakers lose calibration and may fail to trip as designed.
- Lack of maintenance accelerates age-related wear and tear.
4. Physical Damage
- Impacts or mishandling can bend/damage components and prevent proper operation.
- Insects or rodents may nest inside breakers and interfere with mechanisms.
Inspecting usage patterns, environmental factors and physical condition provides clues to what caused the failure.
How to Test and Confirm Faulty Circuit Breakers
Several hands-on tests can confirm suspected circuit breaker issues:
- Overload test - Temporarily overload the circuit with a heavy load and check if breaker trips. Failure indicates worn out trip mechanism.
- Contact resistance test - Use a multimeter to check resistance across closed breaker contacts. High resistance indicates corroded/damaged contacts.
- Insulation resistance test - Use a megohmmeter to measure insulation resistance between hot circuit and ground. Low values can point to moisture damage.
- Trip current test - Pass measured amounts of current through breaker and check tripping threshold. Inaccurate thresholds mean calibration issues.
- Voltage drop test - Check feed and load side voltages for abnormally high drop across breaker contacts indicating pitting or burning.
Performing systematic tests verifies the exact nature of the underlying problem.
Replacing Commercial Circuit Breakers
Replacement is needed when breakers cannot be repaired cost-effectively:
- Replace breakers with equivalent make/model where possible. Refer nameplate ratings.
- For older panels with obsolete breakers, choose replacement breakers listed as acceptable substitutes.
- Follow local electrical codes and device manufacturer instructions.
- Only use properly rated breakers - avoid oversized breakers.
- Test new breaker thoroughly before returning system to service.
Circuit breaker repairs or replacements should only be done by qualified electricians due to complexity and safety considerations.
Preventive Maintenance for Reliability
Regular maintenance is key to minimizing circuit breaker issues:
- Annual inspections to check for damage, corrosion and calibration.
- Testing trip thresholds every 2-3 years per IEEE and ANSI standards.
- Tracking loading on each circuit to avoid overloads.
- Keeping breaker enclosures clean and dry.
- Ensuring tight wire connections.
- Worker training on electrical safety and proper handling.
Preventive maintenance and overload protection extends breaker lifespan and avoids disruptive mid-cycle failures.
Conclusion
Faulty circuit breakers are a serious issue in commercial buildings and can lead to fires or equipment damage if not addressed promptly. However, with proper safety procedures, testing and preventive maintenance, potential breaker issues can be caught early and corrected. Reaching out to qualified electricians is recommended when replacing or servicing commercial circuit breakers due to their complexity and hazardous nature.