Could recent electrical work cause lights to dim when A/C turns on?


Find out what the A/C guy did. I would guess he did something which improved the performance of the A/C system, so now, instead of the motor nearly freewheeling against little load, it's having to hunker down and really work. The increased amperage is "bringing to the surface" a pre-existing problem with wiring, probably between the sub-panel and the supply.

I would now measure to see how serious the problem really is. It may not be worth worrying about, it may just be over-sensitive bulbs.

You can mask the symptom by buying modern lamps. Any multi-voltage rated LED (typically 100-240V) or fluorescent tube ballast (100-277V) will ride through voltage sags. Avoid the cheapies (Feit, Utilitech, Lights of Amerchina, and CFLs of any make; you will not be satisfied with their long-term performance, and they will give LED a bad...

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We've been having problems with our lights dimming recently. We've had similar problems with bathroom fans slowing, plus the TV and dishwasher will reset.

I have a suspicion that it caused by the fridge. It's been making bad motor sounds and freezing up. When we unplug the fridge, it seems to stop our issue with the lights dimming. When we plug the fridge back in, the lights immediately dim for a second and then the periodic light dimming starts back up.

My question is whether a fridge can draw enough power to cause dimming throughout the house. I know there's an initial surge when you plug in a big appliance, but shouldn't it immediately settle down? If it's causing further periodic dimming, then is there something wrong with the fridge? Or could this be a wiring issue?

I know this is hard to diagnose from afar, but looking for some opinions to point me in the right direction (new fridge or call an...

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You and your neighbor may very well be on the same power mains feed. Any heavy current draw on one branch of the circuit will be seen as a voltage droop back up the line toward its source. As that droop passes the point where your mains connection joins in with the neighbor's mains your branch will see a corresponding droop in voltage. This can lead to a dimming of your lights.

This type of voltage droop will always exist in power feed circuits due to the resistance in the wiring. The designer of a power distribution system simply selects wiring sizes with low enough resistance (i.e. fatter sized wire) to keep the droop small enough that it does not create annoying and functional problems with devices attached to the power source. It would appear that in your case the power feed system is not designed with large enough wiring to keep droop to a tolerable level for the loads it is expected to supply. Often the case is that a power distribution network may be designed for a...

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It is certainly not normal. The power system is unable to adapt to sudden increased demand. A typical hardware store outlet tester will probably not help. They only identify grossly bad wiring, such as reversed wires, open grounds, etc. The only wiring that should be in common with the lights and micro is a sub or main panel. If they are on the same circuit, they shouldn't be.

All your panels, as well as devices on the affected circuits, should be inspected for any poor wiring installation. I had a similar problem. I went over my circuits, panel, and service entrance carefully, even redoing some connections though they appeared fine. Never found anything wrong. Eventually, the power company replaced the cable supplying our neighborhood and the problem went away. I cannot imagine how a home appliance could have any effect on a 14.4kv supply, but the problem may not be you.

If your wiring checks out, sounds like a UPS would be a good idea. Also ensure any other...

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Oct 7th, 1999

Lights Flicker (Dim) When A/C Starts

Mike, do you have any information or articles on the possible causes of a new home lights flickering/browning when the appliances or heating and cooling systems are cycling on? I am trying to determine my problem in my home. Is my house getting the proper supply or does my panel breaker box have code violations? Three 3 electricians have looked at my problem and none of them have been helpful at all.

Mike Holt’s Note: The lights at my new house in Central Florida dim each time the heat-pump compressor starts. It’s been that way since I moved in two years ago, but I just didn’t want to take the time to fix it (you know the shoemaker’s kids go barefooted). But since I got so much mail with so many different opinions on this subject, it became a challenge for me to find the problem. So I decided to take the time (about 6 hours) to find why my lights dimmed. And I did, but my lights still dim each time...

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Lights dim when idle - what could be the cause?

I've noticed this before but today it was really noticeable on my way to work. I drive on a route that goes from speeds up to 55 mph to stoplights. What happens is when I arrive at a stoplight (my headlights are on) and my car begins to idle, the idle sounded like it dropped down a bit and my headlights would go dim. Then the idle immediately picks back up and they go back to normal. Then...30 seconds later or so it would drop back down and my headlights would dim for a second before going back up. What causes this and do I have to worry about it? I always assumed that the headlights ran off the battery but then I thought that maybe they rely on the alternator and since the engine idle drops, the alternator in turn drops and maybe that is what is causing them to go dim briefly.

2010 Fit sport


I've also heard it could be due to the fact that I am...

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If your lights Dim When Appliances Turns On in Oakland CA you might have an electrical problem. Signs you might have an electrical problem might include: house lights dim randomly, lights dimming in house when ac comes on, house lights dim when appliance turns on, lights dim in house when vacuuming. What causes lights to dim and flicker? Now you should consider hiring a licensed electrician.

A licensed master electrician can work unsupervised, obtain electrical permits, and start and run a business. The master electrician can check out the wiring in the area you suspect there to be a problem. A certified electrician or master electrician can help you obtain the proper permits needed for the specific jobs you want done as well as help in getting an electrical inspection done on the new electrical services you have received. Only the Master Electrician can pull the permits with the electrical authority and can only be registered with one electrical contracting company at any...

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Dimming Lights and Electrical Problems

Electrical Question:

There is one circuit in my home that dims than regains power several times in a row.

It’s not a flicker and at times everything seems normal, plus it doesn’t matter if one rooms’ electricity is being used or several. I have replaced the circuit breaker for that line, but still the problem exist. There has not been any reconstruction on this 55 year old house for over ten years and any new upgrades utilize their own separate circuit. I have considered there may be a bad rheostat (dimmer) switch in the line, but I’m not sure how to make an accurate meter check. Aside from the frustration, I am concerned that there may be a short or bad wiring that could cause a fire.

Please reply ASAP.

Thank you
Background: Greg, from Massapequa, New York.

Electrical Question #2: I would like to know why everything gets dim in my house when the microwave is turned on, or the dryer is...

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You don't necessarily have a problem or need an upgrade. It is also not usually dangerous, more just a nuisance. Truthfully you would never know if your lights didn't dim momentarily.

Most motors will draw between 4 and 6 times rated current during starting. Most equipment will have some sort of inrush current when first turned on. The TV will degauss its self and the CPU's power supply will have inrush.

If these are on the same circuit as your lights then you will get a slight dim. This is because the momentary high current will produce a momentary voltage drop on the circuit. After this inrush is over the momentary drop ends and your lights brighten.

If this is a single circuit you can alleviate the problem by moving the loads off of a circuit that feeds the lights. If this cant be done by just moving to a different closeby receptacle then you may have to rewire to get the lights and receptacles on different circuits. If this is a branch circuit problem like this an...

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Electricity makes our modern world possible. Without it, we would have no cell phones or dishwashers or

air conditioners

. But it can be a frightening foe when it starts to misbehave. Many homeowners notice that their lights flicker when their air conditioner turns on, prompting them to call an electrician or air conditioner professional in a panic. Does that flickering mean there’s something wrong with the power or the air conditioner?

When the Lights Go Dim

If you think of the electricity in your home’s wiring like the water in your plumbing, it can make it easier to understand why flipping on the air conditioner can make the lights dim briefly. Like the water in your pipes, there is only so much electricity to go around at any given time, especially in older homes with smaller electrical mains.

When you turn on a high-demand appliance like a modern air conditioner, the initial power cost can put a massive drain on the available electricity....

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LED lighting in the home is becoming more popular due to the energy and money saving benefits it offers over traditional halogen lighting. One of the most common problems that an electrician faces when installing LED’s is enabling them to dim.

Resistive Dimming

Resistive dimming has become a standard way of dimming halogen lighting and it works by reducing the voltage allowed to the bulb with a variable resistor.

A resistive dimmer switch is easy to install because it is simply wired between the mains (240V) power and the bulb, however whilst the lighting is dimmed the voltage resistance is converted to heat and is not considered energy efficient.

LED’s use between 12V to 48V so a transformer is required to convert mains power (110V-240V) to the required reduced voltage. Using a resistive dimmer between the main voltage and the transformer will damage the transformer and using a resistive dimmer between the transformer and...

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Hi beauregard, Here are a few links that have some related info regarding "voltage sags" in your home's electrical system. [ ] [ ] [ ] -=- -=- -=- -=- -=- -=- -=- -=- -=- -=- -=- ELECTRIC MOTORS AND BACK EMF [ ] {two types of motor to consider} DC motors, where a coil carrying a DC current (provided e.g. by a battery) is put into rotation by the torque generated by the field on the current. {and} also AC motors, where the current in the rotating coil is the Alternating Current supplied by the power company. For either type of motor we have to deal with a special effect, again due to electromagnetic induction, that goes under the name of back EMF. Here is what goes on : as a coil rotates in a magnetic field region, it sees a varying flux and, as...
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Car problem(s) with the 2006 HYUNDAI SONATA. This database includes information received by NHTSA from consumers either directly or as recorded by the Vehicle Safety Hotline. This information may be used by NHTSA during the investigation process. You may file your own complaint by calling the NHTSA Monday-Friday 8am to 8pm at (888) 327-4236, TTY: (800) 424-9153. You can also file your complaint online.

Jul 16, 2016 - Fond Du Lac, WI - Electrical System
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Electricity is a mystifying force.

You would think that throughout the world there would be standardization everywhere — because touching the wrong live wire can result in burns, shocks, or even death.

When you take into consideration that, even in the RV world, you are likely to run into a number of different electrical systems, the potential for harm is everywhere.

If you know anything about electrical systems, you will rapidly discover that the only thing standard is the fact that nothing is standard between household systems, automotive systems, and marine systems. Each separate area does things its own way and some areas will conflict with other types of systems.

Because of this fact, it is critical that the prudent RV owner understands that if you are not 100% confident in what you are doing, leave electrical issues to the professionals.

Besides injury or death, you could easily destroy thousands of dollars in RV electrical gear by...

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I was just wondering if anyone has experienced the problem I am having with the gas gauge on my 75. It started when I filled it to the top of the tank, for an out of town trip to Edmonton. The tank registered full and dropped normally during the trip. Upon arrival, I still had about half a tank, which is normal for that trip from here (Calgary). I filled up again to the top for the return, and again arrived home with the tank about half full. I drove around town for about a week on what seemed to be a bottomless gas tank as the gauge dropped ever so slowly throughout the week. Finally one day on the way home from work, it stalled as I was doing about 70 km/h down the road. The gas gauge still read 1/4 full and the low fuel light hadn't even come on. Thinking I had really blown something, it took me a while in the middle of the turn lane of a major intersection, to realize that I was somehow out of gas. After trying the great idea of putting a...

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