In diagnosing the cause of flickering or dimming lights at a building the following diagnostic questions can help narrow down the cause of the trouble.

1. Is the dimming light problem happening in just your building or do neighbors see the same problem at exactly the same time? If your neighbors are seeing flickering or dimming lights too, chances are the problem is in the electrical supply network or possibly at local electrical wiring in your neighborhood or its power transformer. If your neighborhood often loses electrical power contact Safe and Sound Electric to install a backup power generator.
2. Is the dimming problem showing up in the whole building or just parts of it? If all lights in the house dim then the problem is probably in the electrical panel or at the service entry cabling to your building. The electrician will look for a problem in the electrical panel, at the main breaker, at the service entry wiring connections or at the SEC wiring itself, including the two hot wires and the service neutral wire. But see the exception in step 4 below.
3. Is the dimming or flickering light problem associated with circuits in just half of the electrical panel? Depending on electrical panel layout, damage to one panel bus can cause failures or odd behavior on electrical circuits connected to that panel bus.
4. Is the dimming light problem associated with the operation of a single, specific appliance or motor? This is an exception to the case described in step 2 in that all lights may dim when there is a developing failure in a single major appliance such as an air conditioner compressor motor. Such motors can draw very high amps (current) for just a moment when the motor is starting. If the current surge is very brief, no circuit breaker may trip but the load may be enough to dim all the incandescent lights that are on or all fixtures in just part of the building, depending on how the appliance circuit is wired in the electrical panel. (Fluorescent lights probably won’t dim). If the problem never occurs when the circuit to that appliance has been turned off you’ve probably found the trouble. If the problem is traced to a specific appliance but is intermittent, other variations in conditions such as temperature, humidity, vibration, or moving around of a loose wire may explain that inconsistency.
5. Is the dimming or flickering light trouble showing up on just a single circuit? In this case we suspect a faulty circuit breaker or bad connection in the circuit. Some circuit breaker brands are particularly prone to failure such as FPE Stab-Lok and Zinsco-Sylvania. In this case the problem may ultimately show up on more circuits in the same building, depending on building age and circuit usage levels and other conditions.
6. Is the dimming or flickering light showing up just at some fixtures or appliances? A likely cause of this problem is a failing appliance or motor that is drawing abnormally high current as we cited in step 3. But sometimes the problem may occur only at lights or appliances plugged-in electrically “downstream” from a specific electrical circuit, or at lights operated by a specific switch. In this case we suspect the trouble is not the appliance itself but in connectors within the receptacle or switch or immediately “upstream” (electrically) from it. Some receptacle and switch types such as older push-in back-wired devices are more likely to have loose or failing electrical connectors with age and usage.

Try plugging in the light fixture or appliance at a different place on a different electrical circuit in the home. If the bad behavior continues then the trouble is in the light or appliance itself.

Watch out: for these safety hazards and take the immediate safety measures listed here. Start by turning off any electrical appliance or circuit that is misbehaving. Call for help from Safe and Sound Electric.

• If your home’s branch circuits (receptacles and lighting) are wired with aluminum wire, flickering, dimming lights or even sparking may show up on just one circuit but the hazard is building-wide and significant. Turn off the misbehaving circuit and have the electrical system inspected and repaired by Safe and Sound Electric who is familiar with the hazards of and proper repairs for aluminum wiring.
• When you can trace flickering or dimming lights to a single appliance, un-plug it and stop using it until it can be inspected and repaired. If the appliance is a unit such as central air or a heat pump, switch it off at the electrical panel.
• When you trace flickering or dimming lights to a specific electrical circuit, turn that circuit off at the electrical panel until Safe and Sound Electric can inspect and repair the problem.
• Call Safe and Sound Electric to help!