Why Do My Lights Flicker When Using A Generator?


Electricity is gradually becoming an essential need for survival. It falls in the same category as shelter, food, and clothing. That is why power outages and flickering are quite annoying.  But, the most dangerous type of light flickering is that of a generator. So why do my lights flicker when using a generator? 

When your generator starts glitching like that, the light will be useless and could damage your appliances. You’re going to find out why your lights flicker when using a generator and how to fix it in this article. 

Why Do My Lights Flicker When Using A Generator?

If your lights flicker when using your generator, it means something is wrong with the generator and its connections. The reason could be a reduction or fluctuation in the voltage delivery going to your house, which causes an abrupt voltage change, manifesting in the bulbs’  brightness fluctuations. 

Light flickering can cause great damage, including fire outbreaks, but understanding why this problem is happening can help you solve it. Below are some of the reasons why your light is flickering when using a generator.

1. Faulty Bulb

A bulb is like a light indicator in the home. It also shows you if the voltage is low or high so it is normal that any disruption in the normal flow of voltage in your house wiring system will reflect in the bulbs. However, a faulty bulb can also cause the lights to flicker. The current might flicker if the bulb is not wound tightly on its hanger or if the lightbulbs are incompatible with your dimmers.

2. Faulty Light Switch

A faulty light switch can also cause light flickering. The light switch is a regulator that allows you to control the bulbs; it switches the light on and off. A faulty switch can cause light fluctuations because the switch can’t stick to one control action. 

A faulty switch is easy to fix. You only have to change the switch. Before continuing the diagnostics, you must check out the lightbulbs first to be sure they are not faulty. 

3. Appliance Overload

A generator is an alternative light source, and as such, it cannot always deliver inexhaustible current or voltage capable of powering all appliances in a home. When the appliances have more load than the generator can handle, there will be voltage fluctuations or flickering from the strain on the generator. 

Excess load on the generator during startup can also cause flickering. It is best to ensure all appliances that drag heavy power, like the microwave and refrigerator, is turned off while starting the generator. You can turn them on once the generator is running at full power. 


4. Generator RPM

RPM is the number of revolutions the generator’s alternator produces per minute. The standard RPM production of a water-cooled generator is a stable and steady 1,800 revolutions per minute. In contrast, that of an air-cooled generator is 3,600 RPM. Any decrease or increase in RPM production will result in voltage instability and electricity fluctuations

The fluctuations are evident from the light bulbs, hence the flickering. Your flickering light issue might result from low or high production of revolutions per minute. You must know your generator type and the standard RPMs it should produce. 

5. Electrical Overloading

Electrical overloading is one of the major reasons for light flickering. Some generators are incapable of carrying appliances with heavy voltage needs. Sometimes you may have different series of appliances that draw lots of current for their use.

If these appliances run on your generator power simultaneously, it can cause the generator to buckle under the load. One of the ways the generator complains about electrical overload is by causing the lights to flicker. It is best to determine the maximum load of your generator and maintain the power level used. 

6. Lose Cables And Connections

Generators are made up of cables and connectors that help deliver the electricity it generates. One of these connections is the neutral plug. The neutral can float or bond but directs current to the output source. 

If the neutral is loosely connected or not fully attached to the generator, it can cause voltage fluctuations. The fluctuations will show or reflect on your light bulbs, causing them to flicker. Check all the generator’s connections to determine that they are well attached and working properly. 

7. Faulty Fuel Line

Generators work with fuel or gas to produce electricity. The fuel line is what delivers the fuel for powering the generator. Any fault in the fuel line will cause a drop in voltage production. The fuel line might leak or tear, which prevents enough fuel from going into the generator. 

Examine your generator’s fuel line for blockage by dirt or leakage. Often, dirt and debris from the fuel tank escape the filter and accumulates in the fuel line. This accumulation prevents enough fuel delivery to the engine. The fuel line is also one of the major reasons for the generator light flickering

8. AVR Settings

Every generator has an AVR setting. The AVR maintains a generator’s voltage at a stable point or value. It also works to convert AC current to AC voltage. Think of the AVR as a thermostat that adjusts the generator’s system as the temperature and load change. It adjusts your generator to accommodate any addition of load and maintains equilibrium.  

Any fault in the AVR will lead to a lack of conversion of current to voltage and can cause electric fluctuations. Fluctuations are the primary reasons for light flickers. To understand this better, think of light flickering as evidence of voltage fluctuations from the generator. 

Other reasons why your light is flickering when using a generator include the following; 

  • A crack in one or more of the generator’s spark plugs.
  • Heavy carbon buildup in the generator’s engine.
  • Sensory circuit overload. A circuit might have more load than it should carry.
  • Poor or irregular maintenance leads to heavy wear and tear of the generator’s parts. 
  • Old age can also cause your generator’s voltage to fluctuate, leading to light flickering. The generator might have exceeded its life span and need replacement.

How Do I Stop The Lights From Flickering On Generator Power?

The first step to stopping the light flickers is to find the causative factor or reason for the flickering. You can do that by running diagnostics on the generator and checking for the reason we listed above.

There are many reasons for light flickering when using a generator. Still, the solution is directly connected to the cause of the fluctuation. Here are some ways you can solve this flickering problem; 

1. Faulty light bulbs

Check your light bulbs and their holders to ensure they work properly. Also, check the dimmers and the bulb connector. Sometimes the bulb might not be sitting properly, causing the light to flicker. 

If your bulbs are faulty, you should change them. If they are not tightly connected to the lamp, tighten them or consider replacing the bulb holder. LED bulbs are more likely to flicker than incandescent bulbs. 

2. Overloading 

Check your manual to find out the maximum load capacity of your generator. Then calculate the total load you are putting on the generator. You can do this by turning off all the appliances in your house and turning them back on one after the other to determine when the fluctuations start. Once the fluctuation begins, avoid putting on other appliances and maintain only the essential ones.

3. Faulty AVR

Check your current lines with an oscilloscope. The oscilloscope monitors the alternating and direct currents. If your AC and DC are not in sync, that may be why the lights are flickering, and you will have to replace the generator’s AVR completely.

Check your generator manual for the right number your AVR should be running on. If it is lower or higher, the controller is damaged and needs replacement. Oscilloscopes are quite expensive so if you don’t have one, it is best to call a technician to check and replace it. 

4. Bad Fuel System

Your generator tank delivers fuel to the engine through pipe and line connections so always ensure that the fuel line does not clog. Clean out the filter and the carburetor from debris and dirt. Check the fuel controller, actuator, and MPU to determine it is in the right setting. If the fuel pump is bad, you will need to replace it. Calling a specialist to examine and change the fuel pump is best.

5. Damaged Cables and Connections

Voltage fluctuations are sometimes due to worn-out cable connections. These wires do not have a permanent lifespan, so with time, they tend to rust or even burn out. Leaking cables can cause voltage fluctuations and light flickering. Check the insulation resistance value of your generator’s cables for shorting. Ensure that they are not rusting, leaking, loose, or breaking. Replace any damaged cable.

6. Old Age

Generators do not last forever. Like all devices or manufactured technology, they have an expiration date and could cause lights to flicker. If your generator is very old, it is time to replace it, so consider getting a new generator. 

Supposedly after these diagnostics, it is time to get a professional if your lights are still flickering. Note that you can only work on or service your generator if you have ample knowledge of how to do so. Without the proper knowledge, you will be doing more harm than good. 


The possible causes of flickering lights when using a generator are numerous and make finding the main cause difficult. But you can start by eliminating one of the possible causes after the other until you find the problem, and this article has done justice to that.

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