Best Answer

A loose or disconnected neutral wire at breaker box or at the appliance. Depending on what is on when and if two or more motors are running at the same time. This can as well have the opposite effect too, lights too bright.

Although loose connection can cause a problem and you should have all the connections checked, it could also be caused by several other reasons. You distance from and the load on the transformer, the size of you service conductors or lateral, the age and maintenance of your appliances. I have found out that light dimming happens in almost every house but some people are more sensitive to it than others.

Usually dimming of lights when an appliance kicks it is caused by a voltage drop of the supply caused by a heavy demand for current when the appliance initially starts. This is usually associated with an appliance that has a motor such as a refrigerator, furnace, washing machine, vacuum cleaner etc. Motors demand about 6 times their steady running current when they first start up and this can be a significant surge of current for maybe a half second or so till the motor has started and is up to speed. This basically momentarily 'overloads' the supply and lowers the voltage available to other devices, thereby causing them to momentarily slow down (if a motor) or dim (if it is a lamp).

If you switch to the new power saving compact spiral bulbs, their internal electronic ballast compensates somewhat for line voltage, so they won't react as noticeably to heavy loads starting up elsewhere in your house. The same is true for fluorescent tube fixtures with electronic ballasts.

One more point:If the lights are on a dimmer, they are very sensitive to change in voltage and will change their brightness disproportionately to the slight changes in voltage caused by motors or other heavier loads switching off and on.
User Avatar

Wiki User

โˆ™ 2015-07-17 17:27:36
This answer is:
User Avatar
Study guides

Add your answer:

Earn +20 pts
Q: What causes lights to dim when the furnace and refrigerator motors come on?
Write your answer...
Still have questions?
magnify glass
Related questions

What runs but cannot?

Motors, watches, refrigerator

Why do the lights in my home pulsate?

By pulsate do you mean flicker. A momentary dimming of your lights can be caused by motor loads on your lighting circuits. If your lights dim, this can be caused by a refrigerator, sump pump, garage door opener or other motors sharing the circuit with your lighting.

What runs but cannot walk?

Motors, watches, refrigerator

What event causes the residents of Maple Street to be concerned?

A loud whoosh and all lights and motors go out on the street. This causes suspicion when first one, then another seem to be unaffected.

How much is a 1930 General Motors refrigerator worth?


What are the advantages to placing lights and motors in parallel?

Cumlitive output

What could cause the headlights to go on but not up on a 1985 Celica GTS if the motors are working?

If the motors are working, then there has to be a problem between the motors and the lights. If they are only "working" though if you bench test them, and they don't actually do anything when you turn on the lights, then there must be an electrical problem such as a break in a wire or a bad ground to the motors.

What kind of products does the Electric Motor Warehouse sell?

The Electric Motor Warehouse sells pool pumps and motors; other pool accessories like fencing, steps, etc.; electric motors like bathroom fan motors, air compression motors, etc.; and specifically a large collection of Dayton electric motors, including furnace blower motors and pressure washer motors.

What electronics uses magnets?

televisions motors , refrigerator , fans , coolers , A.Cs and much more.

What causes the lunar halo on the moon?

General Motors.

Where can one find a furnace blower motor?

Furnace blower motors are easily found at HVAC installers and repair centers. However, without proper knowledge, a customer should not try to fix this, it can be dangerous.

Did egyptions have electricity?

No at least not in the way we do to run motors lights and electronic equipment.

People also asked