Flickering Lights vs. Momentary Dimming: What Your Electrical System Is Telling You

Have you ever noticed your lights dim for a moment and then return to full brightness? Or perhaps you've seen them flicker like a disco strobe? While these may seem like similar issues, they have very different causes—and understanding the difference can help you identify potential electrical problems in your home.

Momentary Dimming: A Common Occurrence

A brief dimming of your lights, followed by a quick return to full brightness, is almost always caused by a motorized appliance starting up. This includes large electrical loads like furnaces or air conditioning compressors, which draw a surge of power when they first turn on before stabilizing. While this can be slightly annoying, it’s generally not a sign of an electrical issue.

Flickering Lights: A Warning Sign

Unlike momentary dimming, flickering lights are a more serious concern—especially if they happen frequently or in multiple fixtures. If you notice flickering in just one light fixture, the problem may be a loose connection at the switch or the fixture itself. In homes with aluminum wiring, flickering could also indicate a failing or burning connection, which should be addressed immediately.

However, if you see flickering lights in multiple fixtures throughout your home, the issue is likely at your electrical service panel.

The Hidden Danger of Loose Neutral Connections

One common cause of widespread flickering is a problem known as "double-lugged neutrals." This occurs when two neutral wires (typically white) are secured under a single screw on the panel’s neutral bus bar. Aluminum wiring is particularly prone to expansion and contraction under load, which can cause these connections to loosen over time. When this happens, neither wire maintains a stable connection, leading to visible flickering as the circuit intermittently loses continuity.

At our company, we address this issue through the COPALUM crimp process, which permanently bonds a copper wire to the end of each aluminum wire. When performing this repair, we also ensure that each neutral wire is properly secured under its own individual screw, eliminating the risk of loose connections and flickering lights.

Don't Ignore the Signs

If you’re experiencing flickering lights, don’t wait until the problem worsens. Loose electrical connections can lead to overheating, arcing, and even fire hazards. A professional inspection can determine whether your service panel or aluminum wiring needs attention, ensuring your home's electrical system remains safe and reliable.