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Published on
November 30th, 2023

The Most Common Causes of Flickering Lights in a Building

Lighting is a safety and functional feature of any New York City property. As a property owner, you understand the importance of maintaining lighting fixtures to ensure people can navigate your building and feel safe entering their apartments.

Unfortunately, because many properties in NYC are pre-war, their electrical systems can be a little spotty. Tenants may complain of flickering lights or temporary service interruptions.

What causes flickering lights? Is it a utility issue, or is it something to do with your building’s electrical system? Discover the primary causes of flickering lights, some minor and others major, and what you can do about them.

What Causes Flickering Lights: The Top 5 Reasons for This Common Tenant Complaint

1. Loose or Improper Bulb

If a single tenant is complaining about flickering lights, the problem is likely local, meaning it stems from inside the unit. Have a conversation with the tenant to find out the frequency and whereabouts of the issue.

Narrowing down the location of the flickering can help you locate a specific fixture that might be the problem. Check the lamp or fixture to see if the bulb or bulbs are loose. If a bulb is loose, the socket receives an inconsistent power supply, resulting in flickering or occasional dimming.

A tenant may also have the wrong bulb for their particular light fixture. For example, if a tenant uses standard fluorescent bulbs in a light tied into a dimmer switch, they may experience flickering. Also, some LED dimmer bulbs only work with compatible LED dimmer switches.

Another common issue is the use of a fluorescent bulb. Many fluorescent bulbs flicker when they are warming up. Tenants may mistake this flickering for a problem with the electricity. You can reduce the number of complaints by updating old fixtures to LED fixtures.

2. Loose Plugs and Old Outlets

As you try to narrow down what causes flickering lights in a tenant’s apartment, don’t ignore lamp plugs or outlets. It is too easy to focus on the fixture and not the power source.

Many times, tenants may not realize that a lamp plug is loose in the outlet. If a plug sits slightly out of an outlet, it causes an interrupted circuit, resulting in occasional flickering. The flickering is most noticeable as movement or weight shifts around or near the outlet.

The plug prongs might cause the shifting out of the outlet, but the more likely culprit is worn-out contact points in the outlet. The points wear down over time, resulting in a looser grip on the prongs of a standard plug. Bolt Electric can resolve the problem by replacing old receptacles with new ones, including modern outlets with USB and charging ports for smart devices.

3. Overloaded Circuits

What causes flickering lights is sometimes the result of something more serious that can present a serious risk to your building. Overloaded circuits are dangerous because they draw too much electricity through one part of the circuit. The draw can cause overheating, arcing, and other potential hazards.

The telltale sign of an overloaded circuit is when flickering lights occur after a large appliance turns on. If the flickering is inconsistent and brief, the issue is likely minor. That said, if the flickering lasts longer than a few seconds and occurs every time an appliance runs, you need to schedule an electrical repair through Bolt Electric.

Unfortunately, circuit overloading is common in the colder months because more people stay indoors. Tenants likely use multiple devices simultaneously to stave off boredom, and they might use space heaters to take the chill out of their apartments. Too many appliances and devices plugged into the same circuit cause significant energy draws, which can present a fire hazard.

To reduce the risks of overloaded circuits, communicate with tenants about electrical safety, especially during more vulnerable times of the year. Also, remember to call Bolt Electric to book your routine electrical maintenance or inspections.

4. Voltage Fluctuation

Voltage fluctuation is another explanation for what causes flickering lights. The standard voltage in residential properties is 120 volts, which means a typical voltage reading should display between 115 volts and 125 volts. If a voltmeter — a tool for measuring voltage — shows a reading higher than 125 volts, it is a sign of a severe fault in your building’s electrical system.

Voltage fluctuation refers to a continuous variation or series of changes in voltage. It usually occurs during the extensive use of devices and appliances that demand higher voltages.

Voltage fluctuation is a serious issue that can cause electrical shock, damage, and fires. You cannot safely correct the issue alone. Only a licensed electrician should investigate and correct this electrical issue. Common signs of voltage fluctuation include:

  • – Flickering lights
  • – Dimming lights
  • – Malfunctioning appliances and electrical devices

5. Loose or Old Wiring

In NYC, loose or old wiring is the most likely explanation for what causes flickering lights, especially in pre-war buildings. As with loose bulbs, loose bulbs interrupt the circuit, causing unpredictable flickering or dimming.

Unfortunately, loose wires are not as easy to fix as loose bulbs, and they often lead to electrical fires. According to the National Fire Protection Association, nearly 70% of residential fires stem from wiring issues.

In pre-war buildings, the issue is likely twofold, with both loose and outdated wiring playing a role in inconsistent lighting. A combination of issues can cause another significant problem: arcing.

Arcing happens when an electrical current bypasses a faulty connection to complete the circuit. The poor connection causes the current to jump, resulting in extreme heat of over 10,000°F, a severe fire risk.

If you suspect your property has old or loose wiring, you need to address it right away. Schedule an appointment with Bolt Electric for a property inspection and maintenance.

What Causes Flickering Lights: Let Bolt Electric Get to the Bottom of It

Avoid Common Electrical Problems With an Annual Service Contract

If you want to find the solution for what causes flickering lights in your building, hire Bolt Electric. Call the service at 212-734-5000 to discuss annual service contracts or request an electrical inspection.


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