How to Troubleshoot Unknown Electrical Faults in Commercial Buildings

Troubleshooting unknown electrical faults in commercial buildings can be a daunting task for even experienced electricians. Commercial buildings contain complex electrical systems with multiple circuits, loads, and potential failure points. However, there are systematic methods an electrician can use to efficiently track down the root cause of unexplained electrical issues. In this article, I will provide a comprehensive, step-by-step guide to troubleshooting unknown electrical faults in commercial buildings.

Gather Information from Occupants

The first step is gathering as much information as possible from the occupants experiencing the electrical issue. Interviewing occupants can provide critical clues that point you in the right direction. Here are some key questions to ask:

• When did the problem first appear? Knowing when the issue started can provide context on what changes occurred in the building.

• Is the problem intermittent or consistent? Intermittent problems are harder to diagnose and may stem from loose connections or faulty devices. Consistent issues likely indicate a steady electrical draw causing a problem.

• What exact symptoms are occurring? Details like flickering lights, tripped breakers, or blown fuses help narrow causes.

• Which circuits or areas are affected? Localizing the issue aids troubleshooting.

• Have any electrical devices been added or changed recently? New loads can overload circuits.

• Does the problem follow any pattern or schedule? Issues tied to certain times may correlate with equipment schedules and help identify loads involved.

Thorough questioning provides critical background info before testing begins. Take detailed notes for reference throughout the troubleshooting process.

Consult Electrical Drawings and Documentation

Next, gather all building plans, electrical drawings, manuals, and documents. Review electrical diagrams, understand normal load levels for each circuit, identify all connected equipment, and note previous modifications. Cross-reference occupant reports of affected areas with the drawings to gain circuit-level insight into the issue.

Pay attention to:

• Circuit wiring paths - faulty wiring may cause problems away from the failure point.

• Load types - large motors and compressors can draw heavy amperage and overload circuits.

• Previous changes - additions or removals altering electrical demand.

• Voltage and amperage ratings - circuits pushed beyond ratings can malfunction.

Accurate documentation saves immense time chasing false leads during troubleshooting. Update diagrams to reflect unrecorded changes.

Visually Inspect the Electrical System

Conduct a visual inspection of the entire electrical system in the building area experiencing issues. Look for:

• Loose or damaged connections - especially in junction boxes and breaker panels.

• Discolored/scorched wires - indicating excessive heat at connection points.

• Frayed/cracked wire insulation - which could lead to shorts.

• Signs of moisture - leaks/condensation near panels or conduits.

• Tripped breakers - identify and reset. Breakers repeatedly tripping indicate overloads.

• GFCI/AFCI outlets - test reset buttons and look for trips indicating ground faults.

• Damaged electrical components - e.g. cracked switch/outlet housings, corroded contacts, etc.

• Melted plugs or cords - caused by high heat from current through faulty connections.

Meticulously inspecting all accessible system components detects many elusive issues missed through testing alone.

Use Testing Equipment to Gather Electrical Data

Testing equipment provides objective data to pursue likely fault causes:

• Multimeter - measures voltage, current, resistance. Tests for shorts, opens, abnormal readings.

• Voltage tester - detects live vs dead circuits. Checks for power at outlets/lights.

• Clamp meter - measures current draws on live circuits. Logs voltage fluctuations.

• Outlet tester - validates proper wiring of outlets. Detects miswires.

• Thermal camera - identifies overheating electrical components. Hot spots indicate problems.

• Breaker finder - tracks which breaker controls specific circuit for testing.

Methodically take baseline readings on circuits to compare with problem areas. Log all test data for in-depth analysis. Capture intermittent issues using monitoring features or data loggers.

Isolate the Faulty Circuit or Component

Leveraging gathered data, compare readings between problem and normal circuits to isolate faults:

• Overloads - high current on affected circuits

• Shorts - low resistance between wires indicating contact

• Opens - no continuity meaning a broken conductor

• Ground faults: current leaking to ground

• Voltage anomalies: fluctuations or deviations from normal

• Wiring errors: crossed wires, reverse polarity, etc.

Use process of elimination to narrow down issues by testing portions of circuits. Turn off breakers and disconnect loads to split circuits and check segments. Locate faults down to specific junctions, loads, and conductors.

Identify the Root Cause

Once the faulty component is isolated, examine it closely to determine the root cause:

• Loose/damaged connections - cause arcing/overheating

• Exposed/degraded conductors - leak current and short

• Faulty devices and fixtures - motors, compressors, lights

• Overloaded circuits - exceed current ratings

• Moisture infiltration - causes shorts and corrosion

• Pests/vermin damage - chew through wire insulation

• Vibration/movement - loosens connections

• Age/wear - deterioration over time

Pinpointing the root cause is key to permanent repair and prevention of recurrence.

Implement Repairs and Protective Measures

Perform repairs to resolve discovered faults:

• Tighten connections - eliminate loose contacts arcing

• Rewire circuits - replace damaged cables and insulation

• Replace devices - change out malfunctioning equipment

• Upgrade conductors - larger gauges to handle loads

• Install surge protection - suppress voltage spikes

• Increase circuits/panels - add capacity for overloaded systems

• Improve sealing - prevent moisture contact with electrics

Implement solutions that not only fix the immediate problem but improve the overall system. Update diagrams with all changes.

Also advise the building owner/manager on protective measures:

• Load balancing - evenly distribute demand across circuits

• Adding circuits - avoid overloads as equipment needs grow

• Load scheduling - sequence large motor/compressor startups

• Insulation monitoring - detect deteriorating wire insulation

• Preventative maintenance - thermal inspections, tightening connections

Proactively improving the electrical system will reduce future faults.

Verify Normal Operation

After repairs, thoroughly test the system to verify issues are resolved.

• Retest previously problematic circuits - confirm normal voltages, loads.

• Run equipment - operate devices, fixtures, and connected loads under working conditions.

• Check for tripped breakers - system should run without new faults.

• Monitor over time - log electrical data to check for normal steady operation.

Only when all tests validate proper function should the issue be considered fully fixed. Continuous monitoring provides peace of mind.

Follow Up On Unresolved Faults

If faults still occasionally occur, it may be necessary to repeat testing to catch elusive intermittent issues. Consider:

• Advanced diagnostic testing - ultrasound, infrared, harmonic analysis, motor circuit analysis, power quality logging

• On-site monitoring - use dataloggers for extended period electrical monitoring

• Partial system isolation - narrow down issue by disconnecting sections

For difficult problems, don't hesitate to call in specialized technicians. Complex electrical issues can require advanced troubleshooting expertise.

Careful diligence and following the right procedures ultimately leads to identifying and resolving every electrical fault.