Troubleshooting Uncommon Electrical Problems in Commercial Buildings

I have been an electrician working on commercial buildings for over 20 years. In that time, I have encountered my fair share of unusual electrical issues that required some creative troubleshooting. Here are some of the more interesting cases I have worked on, along with how I went about diagnosing and resolving the problems.

Faulty Emergency Lighting Systems

Emergency lighting systems are critical safety components in any commercial building. They provide illumination during power outages so people can safely exit the building.

One uncommon issue I have seen a few times is an emergency lighting system that seems to randomly fail - some lights work while others do not. Troubleshooting steps I take:

• Check the circuit breaker and fuses - ensure they are not tripped or blown. Reset breakers and replace fuses as needed.

• Inspect the battery - emergency lights have rechargeable batteries that must be maintained. If the battery is dead or corroded, it can cause operation failures. I replace defective batteries.

• Test the charging system - emergency light batteries are kept charged by a dedicated charging system. I use a multimeter to check the voltage at the battery to confirm proper charging voltage is present.

• Check the lights themselves - faulty lights can cause sporadic outages. I replace any emergency lights that are flickering, dim or fail to turn on when tested.

• Verify proper grounding - ground faults can impact emergency lighting operation. I check grounds with a multimeter and repair any issues found.

With persistent issues, I dig deeper into the wiring itself, inspecting connections and junction points. The specific causes vary, but methodically working through these troubleshooting steps allows me to zero in on the root of the problem.

Power Surges in Select Circuits

Power surges or unexpected increases in voltage can damage equipment and disrupt operations. Isolating the source of these surges is important.

If elevated voltages affect only certain circuits, I inspect:

• Connections to affected circuits - loose wiring can cause arcing and voltage spikes. I tighten all connections and replace any damaged wires.

• Circuit loading - overloading circuits strains the system and can lead to surges. I evaluate the devices on affected circuits and redistribute load if needed.

• Shared neutrals - when a neutral serves multiple branch circuits, an imbalance can cause surges. I check for shared neutrals and rewire if found.

• Proximity to heavy-draw equipment - large motors, compressors, elevators etc require high startup current, which can spike voltage on nearby circuits. I reroute any affected circuits if possible.

• Damaged transformers - faults within a transformer can cause poor voltage regulation. I isolate and test suspect transformers, replacing any with internal faults.

Paying close attention to which specific circuits are impacted helps narrow down the potential causes quickly. I also use multimeters to check voltages and current draws throughout the system to aid troubleshooting.

Intermittent Ground Faults

Ground faults occur when electricity leaks to the grounding system rather than following the normal circuit path. Intermittent faults that come and go are especially tricky.

To find the source, I:

• Check ground connections - loose connections can arc on and off, causing intermittent faults. I verify tight, corrosion-free connections at panels and devices.

• Inspect wiring - damaged insulation allows arcing to ground. I look for any cracked, burnt, or degraded insulation along the circuit.

• Use a clamp meter - I clamp the meter around the hot conductor and check for current leakage to ground. I take readings at multiple points to narrow down the fault location.

• Consider moisture issues - moisture penetration can create intermittent conductivity to ground. I inspect for any signs of liquid incursion into conduits or junction boxes.

• Document observations - I record details about the fault frequency, weather conditions, affected locations, etc. Patterns often emerge that aid troubleshooting.

Intermittent faults take patience and careful observation. I often have to spend significant time monitoring and taking measurements before the issue reveals itself. But systematically working through the circuit I can eventually isolate the problem.

Motor Operation Issues

Motors are used extensively in commercial buildings, driving air compressors, pumps, conveyors, chillers, and many other devices. When motors act up, production can grind to a halt.

Some common motor issues I troubleshoot include:

• Overheating - caused by overload, voltage imbalance, mechanical binding, blocked ventilation, or electrical faults. I check amp draw, voltage at all 3 phases, fan operation, and windings.

• Vibration - due to misalignment, unbalanced rotating parts, bad mountings, or worn bearings. I inspect couplings, pulleys, belts and hardware for tightness.

• Insufficient torque - from low voltage, single phasing, mechanical overload or incorrect sized motor. I verify proper voltage under load at each phase and the starter size.

• Starter failure - malfunctioning motor starters can prevent proper starting. I test and rebuild or replace starters as needed.

• Open windings - caused by motor faults or overvoltage spikes. I perform resistance tests on all windings and megger the insulation.

Good motor maintenance and monitoring are key. But when problems do arise, I take a methodical approach to troubleshoot based on symptom patterns and use parameters like current draw, voltage, resistance, and vibration. This allows reliable identification of the root cause.

Lighting Flickering Issues

Troubleshooting lighting problems seems straightforward but can have some nuances. Flickering lights are a common complaint in commercial buildings. Several key factors I inspect are:

• Loose connections - whether at the fixture, in junction boxes, or at breaker panels. Tightening all connections often fixes flickering issues.

• Voltage drops - from overloaded circuits or excessive wire runs. I calculate loads and distribution to ensure voltages remain within parameters at all fixtures.

• Failing ballasts - older fluorescent fixtures with magnetic ballasts are prone to flickering when ballasts heat up. Replacing magnetic ballasts with modern electronic ones solves this.

• Incompatible lamps/ballasts - mixing different tube types (T12, T8, T5), lamp wattages, or ballast-lamp combinations on a circuit causes flickering. I standardize all lamps and ballasts.

• Defective fixture - sometimes the lamp socket, wiring, or entire fixture assembly is faulty. I systematically replace components until the problem is resolved.

Lighting issues seem simple but can persist if these less obvious factors are not considered. My detailed troubleshooting process allows reliable identification and repair of even tricky lighting problems.

Power Factor Correction Failures

Power factor (PF) measures electrical efficiency. Commercial buildings often use power factor correction (PFC) capacitors to maintain optimal PF and prevent penalties from the utility. Failures in PFC capacitors or systems cause headaches.

To troubleshoot, I:

• Check capacitor status indicators - modern PFC systems have indicator lights showing capacitor bank status. Any fault lights help isolate the issue area.

• Inspect capacitor connections - loose wiring leads to faults and hurts PF correction. I verify tight, clean connections at all banks.

• Check capacitor integrity - leaking electrolyte, bulging cases or blown pressure relief valves indicate capacitor failure. I replace any defective capacitors.

• Confirm proper capacitor sizing - under or oversizing capacitors reduces PFC effectiveness. I calculate ideal capacitor bank sizes based on equipment loads.

• Evaluate overall PFC system design - problems are often rooted in improper system design and controls. I audit the entire system and modify as needed.

Paying close attention to the PFC system design flaws, capacitor maintenance and timely replacement of aging components is key to avoiding power factor issues.

Conclusion

Years of experience troubleshooting electrical systems provides me insight for diagnosing tricky, uncommon issues that stump less seasoned technicians. While every case is unique, following a methodical process focused on parameters like voltages, loads, connections, etc allows reliable identification of the root causes. Understanding commercial building electrical systems at a deep level is critical for efficient troubleshooting. Proper prevention and maintenance also helps minimize these types of problems.