Ceiling fan causing tv to flash?

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travish

Member
Location
Central North Carolina
Occupation
Electrician
Customers living room has only 1 - 20a circuit that supplies all the receptacles and the ceiling fan/light. The trouble is when the ceiling fan is switched off the tv blinks. It is actually it is the cable box that is blinking but it shows up on the tv. (If the tv is running on antenna it doesn't blink). If I plug the cable box up to another receptacle somewhere else in the house with a drop cord there is no blinking. I have taken down the ceiling fan and it is properly wired and grounded. I am guessing the capacitors in the fan is causing something the cable box doesn't like.

Do you think some kind of surge protector would correct the issue? or does the fan need replacing. I don't have a Oscope to look at the circuit with, but I don't see any voltage spikes with my voltmeter?

Thanks
Travis
 

mopowr steve

Senior Member
Location
NW Ohio
Occupation
Electrical contractor
I had a similar situation while adjusting wall speed control in my kitchen. When I would turn the control off the tv nearby would emit a small pop sound from the speaker.
Probably the small spike from capacitive/inductance from fan and control.
 

Sierrasparky

Senior Member
Location
USA
Occupation
Electrician ,contractor
Try hooking the fan up to the extension cord and see what happens. Try powering from the same room and then from another. Power all from the other room and see if the problem continues.
 

goldstar

Senior Member
Location
New Jersey
Occupation
Electrical Contractor
Sounds like something might be wired in series. Any chance the receptacle for the TV was switched at one time and is still controlled by the wall switch or speed control for the fan ?
 

kwired

Electron manager
Location
NE Nebraska
plug at least a 500 to 1000 watt resistive load into the receptacle supplying the TV and see what the voltage does when you apply that load. If it drops severely, you have loose connection(s) or even the fan wired in series with the outlet like mentioned earlier.
 

curt swartz

Electrical Contractor - San Jose, CA
Location
San Jose, CA
Occupation
Electrical Contractor
I went on a service call for a builder with a similar problem a couple of years ago at a new townhouse. Every time the paddle fan was turned on/off in the family room the TV picture would go black for a few seconds. Customer, Builder and EC insisted the receptacle was turning off. Original EC could not figure it out. I was able to produce the problem but determined quickly there was no way the receptacle was loosing power. The picture would comeback within a few seconds. If the receptacle lost power it would take several minutes for the equipment to reboot. I knew the fan control had to be causing RF problems with either the TV or DTV receiver. I swapped out the crappy $.99 HDMI cable and the problem went away.
 
Customers living room has only 1 - 20a circuit that supplies all the receptacles and the ceiling fan/light. The trouble is when the ceiling fan is switched off the tv blinks. It is actually it is the cable box that is blinking but it shows up on the tv. (If the tv is running on antenna it doesn't blink). If I plug the cable box up to another receptacle somewhere else in the house with a drop cord there is no blinking. I have taken down the ceiling fan and it is properly wired and grounded. I am guessing the capacitors in the fan is causing something the cable box doesn't like.

Do you think some kind of surge protector would correct the issue? or does the fan need replacing. I don't have a Oscope to look at the circuit with, but I don't see any voltage spikes with my voltmeter?

Thanks
Travis


I would by a $30 UPS (APC) and be done with it. They do a good job of cleaning up power and if it doesnt work, customer can return it to Walmart.
 

Little Bill

Moderator
Staff member
Location
Tennessee NEC:2017
Occupation
Semi-Retired Electrician
Sounds like something might be wired in series. Any chance the receptacle for the TV was switched at one time and is still controlled by the wall switch or speed control for the fan ?

plug at least a 500 to 1000 watt resistive load into the receptacle supplying the TV and see what the voltage does when you apply that load. If it drops severely, you have loose connection(s) or even the fan wired in series with the outlet like mentioned earlier.

OP said it wasn't the TV but the cable box, it just shows up on the TV.

It is actually it is the cable box that is blinking but it shows up on the tv. (If the tv is running on antenna it doesn't blink).
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
OP said it wasn't the TV but the cable box, it just shows up on the TV.
If the only evidence that the cable box "blinks" is what is seen on the TV, that still allows for digital interference on the HDMI cable, requiring the TV to spend a few seconds resynchronizing. I vote for that as the most likely option.
I think most of us have seen the delay before the picture appears when plugging in an HDMI cable.
 

Little Bill

Moderator
Staff member
Location
Tennessee NEC:2017
Occupation
Semi-Retired Electrician
If the only evidence that the cable box "blinks" is what is seen on the TV, that still allows for digital interference on the HDMI cable, requiring the TV to spend a few seconds resynchronizing. I vote for that as the most likely option.
I think most of us have seen the delay before the picture appears when plugging in an HDMI cable.

My point was that it wasn't the receptacle for the TV since he said it didn't do it when using an antenna, bypassing the cable box.
 

mgookin

Senior Member
Location
Fort Myers, FL
If the only evidence that the cable box "blinks" is what is seen on the TV, that still allows for digital interference on the HDMI cable, requiring the TV to spend a few seconds resynchronizing. I vote for that as the most likely option.
I think most of us have seen the delay before the picture appears when plugging in an HDMI cable.

I have never hot plugged a HDMI or a SATA even though they are both supposed to be hot pluggable.
Just seems safer to have no signal going through when doing it.

Between your statement and a previous statement that the same issue was cured with a better HDMI cable, I'll vote for this as the most likely solution as well.
 

10fords

Member
Location
California
Are the bulbs in the fan light LED? I recently installed Led's at a business (nursery) and now when they shut off the fountains the music system shuts off for a few seconds! - Scott
 
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