PC fan connected to wall adapter causing lights to flicker

Thread Starter

s355

Joined Apr 13, 2021
32
I am plugging a 12v CPU fan into a 12v power adapter, but starting the fan is flickering the lights. How should I fix this?
 

Thread Starter

s355

Joined Apr 13, 2021
32
It depends on what lights are flickering.

If it's house lights, unplug the thing and call an electrician.
It's only flickering the house lights while starting. While running, the lights don't flicker.
 

Reloadron

Joined Jan 15, 2015
6,064
Just like your last thread. OK, the fan is 12 volts 300 mA according to your last thread. So what exactly is the power supply? Even if the fan overloaded a small 12 volt supply I really can't see how it would make lights powered off mains power flicker. Try placing a large cap across the DC supply like 470 uF 25 volt rated. What id your mains voltage?

Ron
 

dl324

Joined Mar 30, 2015
13,141
It's only flickering the house lights while starting. While running, the lights don't flicker.
If something drawing a few 10's of mA can cause your house lights to flicker, you have a serious problem with your house wiring. Since you're asking very basic questions, you aren't qualified to troubleshoot the problem.

Call an electrician before your house burns down.
 

MisterBill2

Joined Jan 23, 2018
9,304
This is indeed a puzzle. So my first suggestion is to plug another load into that same outlet and see if switching that on also makes the house lights flicker. If it does, then it is some sort of serious house wiring issue. But the first diagnostic act will be to tap the outlet, rather gently, and see if that also makes the lights flicker.
One other thing, a question: Are those flickering lights LED lights fed by a dimmer? My experience is that some dimmer-controlled LED lights flicker from any noise on the AC mains. If that is the case there is no issue.
 

MisterBill2

Joined Jan 23, 2018
9,304
That symptom seems like a bad connection in the outlet box sort of fault, A loose connection or a cracked conductor in the outlet. Quite a simple repair projet, but please switch off the power to the outlet before getting into it.
 
Last edited:

Reloadron

Joined Jan 15, 2015
6,064
@Yaakov Just the lights in the room where the fan is connected.
Then start looking for a poor wiring configuration. Something is loose somewhere. A simple light load should not create a flickering light(s) issue. Now if you have no understanding of branch circuits or how things work I suggest you find a competent qualified electrician to review the problem.

Ron
 

Tonyr1084

Joined Sep 24, 2015
6,269
Good house wiring or not - if lights are flickering then get rid of that power supply. It's probably made in China and is probably cheap. And dangerous. Virtually all 12V power supplies I have laying around, are at least 5 amps. If what you have is from a 12 volt battery charger intended for something like a rechargeable flash light - then chances are good it's of poor design and may be faulty.
 

Tonyr1084

Joined Sep 24, 2015
6,269
Does the issue continue to occur even when you plug it into a different outlet? Different room? If the problem follows the PS then the PS is likely the problem. If it's only in the one room then it's house wiring issues.

I once had a halogen lamp in my room. When I turned it on - sometimes it made half the power go out. But when I turned the electric stove on all power came back. The issue was in the meter box. A loose wire. Turning on the very heavy load welded the loose wire in place, but when small loads like the halogen lamp came on it could break that weld.
 
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