Dimming lights

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zappa

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Howdy Folks!

Sometimes at night I sit here and can literally see the lights in my house dim for a nanosecond - or two Nothing loses power or resets and it doesn't seem to follow any type of pattern. It does not do it every night either - just randomly anywhere from One to Five times a minute.
It also does not seem to have any relationship to my air compressor in the garage, Fridge or dishwasher either.

What is it and how can I narrow it down? Should the poco be informed?
 
If you are concerned, call an electrician to come in and perform a power quality check. He can also advise you on whether or not you need to get the POCO involved.
 
Sounds like neighbors' power usage, if not something in your own home. Electric heat of some kind? Tankless water heater?
 
If it isn't something in your house kicking on and off (and it probably is) then it is something in the guy next door's house kicking on and off.

Also, I'm curious to know how you timed the 2 nanoseconds...? :D That must be a pretty good stopwatch.





You don't have a 'garden' in your basement using a bunch of power, do you? :D;)
 
Check you circuit brakers. move them just a little bit and listen for a crackling sound. If you do hear crackling then its time for a new panel because your buss has been damaged do to arcing. Call your electrician. Post the outcome please.
 
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There are several issues here,

Possible loose neutral which needs attention IMMEDATLY. This can be from the transformer to your branch circuits.

Flicker< which can be something you are dingf (motors starting or possible a neighbor issue, depending on the utility distribution in your area.


Light flicker (dimming and restoration of light to near preflicker level) of lights from motor inrush) is a byproduct of several factors and generally is difficult to over come.

AC motor loads (in particular compressors) but all motor loads have inrush currents. These inrush currents result in voltage drop in the branch circuit, panel bus, service laterals, utility transformer and possibility the utility HV feeders.

Flicker is in addition user dependent; some people are more susceptible to flicker. For some reason flicker seems to bother women more that men (based upon personal experience).

A Voltage Drop (VD) as little as 3 volts on a nominal 120 VAC system is noticeable (by me), 2.5% VD.

We have had cases were the VD was all a byproduct of primarily single phase 120 VAC loads, in these cases we were able to put the lighting on L1 and all the motor loads on L2, the HVAC compressors were something the homeowner had to live with. This minimizes the flicker.


To test for this VD and resulting flicker to determine the source of the inrush, use a min max amp clamp and min max multimeter at the main service watch the lights(it may take two workers) and correlate to the meters.
 
zappa said:
Howdy Folks!

Sometimes at night I sit here and can literally see the lights in my house dim for a nanosecond - or two Nothing loses power or resets and it doesn't seem to follow any type of pattern. It does not do it every night either - just randomly anywhere from One to Five times a minute.
It also does not seem to have any relationship to my air compressor in the garage, Fridge or dishwasher either.

What is it and how can I narrow it down? Should the poco be informed?
Click to expand...

Do you have dimmers on the lights that are dimming? Do you have well water? If so on both then dimmed lighting is more susceptible to dimming on motor inrush currents. If you have well water then it could be that pump turning on and it is something that you are possibly overlooking due to the motor not being in the house so it is almost silent. (except for pressure switch actuation and check valve chatter)
 
090513-0829 EST

Here are some related threads on this forum:

http://forums.mikeholt.com/showthread.php?t=111772
http://forums.mikeholt.com/showthread.php?t=107858
http://forums.mikeholt.com/showthread.php?p=945445
http://forums.mikeholt.com/showthread.php?t=68580
http://forums.mikeholt.com/showthread.php?p=1015823
http://forums.mikeholt.com/showthread.php?t=93189

On a pulsed basis to an incandescent lamp I can see minor flicker on a 1 V change at 120 V nominal. I would not likely notice this as a single random event while reading the paper.

.
 
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