What Is Causing My House Lights To Dim?

House Lights going Dim

It can be scary moving to a new house or apartment, especially if the establishment is old to the neighborhood. Sometimes the doors creak a little more than you’re used to, or the cabinets don’t shut all the way, or the appliances fail to operate correctly. When I first moved to my new/old apartment, I faced all of these minor annoyances. However, none were as alarming as one peculiar phenomenon: every time I used my microwave, the lights would flicker and dim until my food was done cooking.

While my meal was always properly warmed and the lights always went back to normal, it was still a little unsettling. Was this indicative of a larger problem? Below, we’ll review the cause of my situation, as well as some other common reasons house lights go dim (other than your light dimmer switch, of course!).

Overloaded Circuit

If your lights dim when you are running an appliance, such as a dryer, air conditioner, or microwave like in my case, check to see if the lights are on the same circuit as the appliance. You might be simply dealing with an overloaded circuit – meaning your circuit is outdated or wired to run more appliances than it can handle. This is typically the case if you are living in an older abode. Although annoying, overloaded circuits due to appliance usage are common and not typically a danger. However, if you find that your lights are dimming beyond the use of the appliance, or if the appliance is tripping your circuit breaker, another reason could be behind the dimming. It’s time to call an electrician.

Problems with the Power Grid

Has your area experienced some bad weather lately? A transformer may have blown, or the service feed coming into your house may have been interrupted. Both are common occurrences during a storm. The problem may even be at the local utility substation. Brownouts (all-around dim lights) are not as common as blackouts, but they can happen when there is a city-wide power shortage or an unusually high demand for power.

Power Grid

Power Grid (From the Utility Station to You)

Improper Wiring

Another reason your lights could be dimming unexpectedly is because the wiring throughout your home is outdated or insufficient to handle the amount of current it uses. When the electrical service has a demand for too much current, the voltage can drop, causing your lights to dim. Many older houses have this problem; they simply weren’t built to handle the electrical loads of today’s modern household, which typically features many devices or appliances that all require large amounts of power. If this is the case, you may require new wiring or a new service – ask an electrician.

Loose or Corroded Neutral Wire

wiresIf the lights in your house are fluctuating between bright and dim, you could have a more serious problem on your hands. You might have a loose or corroded neutral wire in your circuit breaker. The circuit breaker contains three wires: the first is red or black (the “hot” wire) the second is white (the “neutral” wire) and the third is a green or bare (the “ground” wire) which is only used for safety purposes. The first two wires are responsible for providing power to your household circuit. The neutral wire simply provides a return path to earth ground in the electrical panel to complete the circuit. A broken neutral wire means that the return path to the electrical panel is incomplete, which can cause imbalances in the two main power wires. When your lights brighten they are receiving too much voltage, and when they are dimming, they are receiving too little. If this problem worsens, your electrical devices could end up receiving far too much or too little power and become damaged. Loose or bad connections are the major cause of fires and other safety hazards. Contact an electrician as soon as possible.

Remember, these are just a few common reasons house lights go dim. There are, of course, many other possibilities. If you have continual trouble with dimming lights, always consult an electrician.

Have your house lights ever gone unexpectedly dim?  What was the reason? Feel free to share with us in a comment or to drop us a line on FacebookTwitterGoogle PlusLinkedIn, or Pinterest!

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Jessica Banke

Jessica is the Lead Copywriter at 1000Bulbs.com, meaning she spends 40 hours a week illuminating the world on lighting topics from A to Z. Otherwise, she can be found on an outdoor patio listening to live music or at home playing with her miniature Australian Shepherd, Sydney. Check back often for more of her fun and practical lighting articles!

  • http://www.lie2us.com/ Lie2us.com

    Wanted to share my experience in hopes it may spare others the nightmare we went through with dimming lights and appliances.

    It started about two months ago, very slowly at first, after thinking I noticed (out of the corner of my eye) a flicker and dismissing it many times, I finally asked my wife if she noticed it and she said she had been seeing it as well. It was sporadic at first, just a flicker but then as time went by the flickers became more noticeable and for longer periods of time. Anything running would seem to have a power drop, running at half speed.
    At that time I called the power company. The crew that came out said it sounded like a neutral problem, they checked my main breaker box and removed the meter and checked the connections. They replaced the connections at the top of the meter loop and checked things at the transformer. They checked the voltage and I was receiving 125volts per hot wire coming into the house. I was hoping what they did would fix the problem, it didn’t and did not take long to see the flickering was not affected by what they had done.
    I called the power company and I was told that possibly my main breaker might be going bad, so I ordered a new one and put it in when it arrived, that too was not the problem.
    I re-contacted the power company and the crew came back again, re-checked things and indicated that the problem was most likely within my home wiring.
    So, I contacted an electrician, he came out and inspected my main breaker box as well as the two sub-panels inside. He found one thing that should be done but said that should not be causing my problem. He put a new neutral cable from the main panel to my first sub-panel, it had been grounded with the several strands of bear twisted ground cable that was inside the wrapped cable of the two hots to that panel.

    He said it should have it own insulated neutral and installed one. This too did nothing to stop the flickering.
    I called the electrician again and he came out and removed everything from the main box, cleaning cable connections and said there was nothing wrong with anything there. He checked both sup-panels, again no problems noted. He finally said it did not seem to be a problem inside since the flickering could not be isolated in either sub-panel, it was always the whole house. He suggested I re-contact the power company saying the only thing left he could do would be to trace out every circuit one by one in hopes of finding a problem, I couldn’t imagine how long or how expensive that would be.
    So I contacted the power company and for the third time a crew came out. This time they said they were going to replace the ground of the neutral line cable from the pole the transformer was on. After replacing the ground, my electrical problems disappeared, that was the problem all along, a corroded ground on the neutral line.
    Now all this went on over a period of at least three weeks from the first time I called the power company and they came out. It was horrendous living with this problem, not knowing if the house would catch fire or all the appliances would give out due to the them running a lot of the time at seemingly half speed.

    Anyway, if you experience anything like I described – tell the service crew to first of all – replace the ground to their neutral cable – it may save you a lot of the grief we had to face until it was finally fixed.

    • jbanke

      Oh wow, that does sound like a nightmare! Thank you for sharing. I hope it helps someone avoid a potentially dangerous situation!

  • http://www.solomoncorp.com/ Ruby – Solomoncorp.com

    I had similar problem some time ago. All the lights in my house dim periodically, but on the other time the light burn out occasionally. It was a nightmare for us. And after we asked a professional help to investigate it, we know that there’s bad connection in the circuit breaker panel.