How to Troubleshoot Obscure Electrical Wiring Problems in Older Buildings

Diagnosing electrical issues in older buildings can be challenging, even for experienced electricians. Here is a step-by-step guide to help troubleshoot some of the most common obscure wiring problems in older structures.

Understanding Electrical Systems in Older Buildings

Older buildings can have antiquated electrical systems that do not conform to modern codes. This makes troubleshooting problems more difficult. Here are some key things to know:

Wiring - Older electrical wiring is often ungrounded and made of materials like cloth-wrapped copper that degrade over time. This can lead to shorts, sparks, and fires.
Fuses - Old fuse boxes use screw-in fuses that can fail over time. Replacing a blown fuse may fix an issue temporarily but doesn't address underlying problems.
Capacity - Electrical systems in old buildings often have insufficient capacity for modern loads like computers and air conditioners. This can lead to frequent tripping of breakers or blown fuses.
Safety Hazards - Outdated wiring and lack of modern safety features like GFCIs and AFCIs create shock and fire risks. Any problems should be addressed immediately.

Diagnosing Electrical Problems

Start by gathering information before trying to pinpoint the exact issue:

Ask tenants - Find out if the problem is intermittent or occurs under specific circumstances, which can help isolate causes.
Check the breaker/fuse box - Note any tripped breakers or blown fuses related to the problem area. Test shutting off breakers individually.
Inspect all visible wiring - Look for damage like cracked/frayed wires, discolored insulation, signs of arcing/sparks.
Take voltage measurements - Use a multimeter to check for normal voltage at outlets and light fixtures experiencing issues.
Evaluate the age and condition of wiring and equipment - Upgrading old panels, rewiring, or replacing obsolete equipment may be needed.

Tracing Wiring Problems

Here are some common obscure wiring issues in old buildings and how to diagnose them:

1. Intermittent Power to One Area

Check connections at all outlets and light fixtures in the affected area for loose, damaged wires.
Inspect the circuit breaker/fuse servicing that area for signs of overload. Test shutting off the breaker/replacing fuse to see if it impacts multiple rooms.
Check for backstab connections on outlets, switches and light fixtures that can loosen over time. Replace affected devices.

2. Lights Flickering or Dimming Periodically

Use a multimeter to check voltage when the issue is occurring. Low or fluctuating readings point to a loose connection or overloaded circuit.
Check for failing bulbs first. Incandescents can dim or flicker when burning out. Replace bulbs that appear discolored.
Remove switch and outlet covers on the circuit and check for arcing or heat damage that causes interference.

3. Outlets Not Working in One Room

Check for a tripped GFCI outlet that may cut power downstream when it trips. Press reset button to restore power.
Test outlets with a plug-in circuit tester. No lights can indicate an open neutral wire. Shut power off and inspect connections.
Try replacing the outlet, as they can fail over time. Verify wires are secure under terminal screws, not just pushed in.

When to Call an Electrician

Consult a licensed electrician if:

You are unsure of the exact problem after troubleshooting.
The electrical panel needs upgrading or rewiring is required.
You discover hazardous wiring conditions like exposed conductors.
Light fixtures or outlets spark, smoke or feel hot.

Obscure electrical issues in old buildings can be tricky but methodically narrowing down causes using voltage testing, visual inspection and by gathering tenant input you can resolve or pinpoint many problems. Calling a professional promptly is recommended whenever the source of electrical faults is unclear or risks are identified. With diligence and the right approach most electrical problems can be solved.