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BANGKOK 25 June 2019 18:31
UniqueWord

Brief interruptions to TV when fans or lights are switched

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My apologies if this has been addressed before.  I seem to recall a thread about it..  But I have searched thru 13 pages of the Elec Forum, and done searches on almost all the key words in my subject today to no avail.

I have a LG LED TV which has a xformer brick to low power DC.  It's connected to the main supply thru a surge suppressor, possibly of questionable utility.  We recently had the ground floor wiring re-housed, not replaced, due to failure of the false ceiling drywall because of insect damage.  At the same time I had the chance to check the colour coding, which follows no standard.  There are black, blue and green solid 4mm2 conductors.  The original wiring was done by a PEA employee in his off time.  The grounding appears to be intact, with phase-neutral at 240V, phase-ground at 240V, and neutral-ground at 0V.  This is the extent of the checks I've been able to make.

We discovered that the MCB for the room that has the TV was only 20A, and were advised to replace it with 32A.

This has not fixed the problem.  I've read elsewhere that this problem may be due to a bad HDMI cable or a bad surge suppressor.  I'd appreciate any insight which you good folks might have.

Cheers, UW.

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If you cant find what's wrong a simple practical solution may be to buy a computer UPS for around 1500B.

 

https://www.jib.co.th/web/product/readProduct/32823/340/UPS--เครื่องสำรองไฟฟ้า--SYNDOME-ECO-II-600--600-VA-360-WATT-

 

Back in Europe where we often had power cuts and lightning strikes during storms I used to run all my PC and AV equipment off three different UPS devices.

 

Here I just use a UPS for my PC as power cuts are very rare in my condo, and when they happen at all they are usually scheduled in advance by the power company.

 

 

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Posted (edited)
27 minutes ago, UniqueWord said:

I'd appreciate any insight which you good folks might have.

what happens when you remove the surge suppressor? and any extension cords.

 

unplug everything from your tv except power. does the problem still happen?

 

is it easy to move your tv to another room and test there?

 

 

Edited by NCC1701A

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Unfortunately it is hard for me to find out what really happens with your TV.

And all the story about the wiring and breakers, still the question is unclear from the post.

 

But when I saw the title 'Brief interruptions to TV when fans or lights are switched' I decicde to open your thread to see, because I had the same phenomen before. And I will explain what.

 

When watching TV, and anything with a induction load like the ceiling fan or airconditioner has sometimes an weird action when they turned off causing the TV signal from the box being disturbed.

It was an DVB Terrestrial receiver, fed the video signal thru HDMI to the TV.

The result was that the screen became blue (as in -no signal-  blue) and a noise, those black white dots you probably remember from the analog era.

Have to wait 10 seconds and the TV signal was back, or after powering off/standby the receiver.

 

What exactly was the cause is still an mistery. No earth is in the game with the TV and receiver so probably some atmosferic stress for a short while and the hdmi or sat/ant cables were functioning as an antenna to pickup those intrasterrrial form of spikes.

 

It was all gone when an another box came in place

(My puppy ate the remote and I choosed to replace the box anyway)

 

Sounds familair in your situation?

 

 

PS.  The 20amp breaker is good enough for one room, I am using  16amp and 10amp breakers here.

 

Rgds,

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Can you make sure that your TV is not on the same power feed as the lights and fans?
Probably turn off the lights and fans breakers and find a power point that is still live and plug the TV into that.
See what happens when you play with the lights and fans again.

Sent from my SM-J700F using Tapatalk

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I am guessing that it is a shared neutral causing this. Lights may be on one hot and the TV on another hot but they share the same neutral.  ???

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^I was just going to post the same.  In my case, it was a fan that would cause a light to flick but a "borrowed" neutral was the cause.

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Just now, bankruatsteve said:

^I was just going to post the same.  In my case, it was a fan that would cause a light to flick but a "borrowed" neutral was the cause.

Great minds think alike I guess!  😉

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Great minds think alike I guess!  
What about me?

Sent from my SM-J700F using Tapatalk

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3 hours ago, longball53098 said:

I am guessing that it is a shared neutral causing this. Lights may be on one hot and the TV on another hot but they share the same neutral.  ???

In the electric circuit at home, the neutral is shared in the consumer unit.

Only the live wires go trough these breakers, unless two pole breakers are used for both L and N.

 

 

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5 minutes ago, donim said:

In the electric circuit at home, the neutral is shared in the consumer unit.

Only the live wires go trough these breakers, unless two pole breakers are used for both L and N.

 

 

Individual circuits consist of L and N (yes, L is on a breaker and N's are on a common bar).  A "borrowed" neutral is when the N for one circuit is also connected to N of another circuit.  IE:  Two separate L, but only one N.  This is not allowed per any code.

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14 hours ago, UniqueWord said:

We discovered that the MCB for the room that has the TV was only 20A, and were advised to replace it with 32A.

 

NO!!!

 

20A is the correct breaker for non-fused Thai 16A outlets even if they are on 4mm2 cable.

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What inputs do you have to your TV?  Since you have a very solidly grounded power system, i would expect either a switched neutral rather than phase, or a ground loop on your Cable or some other input. 

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Voltage in Thailand is 220 V not 240 V. If you measured 240V something is wrong.

 

The most likely cause is something in your TV. I have a Toshiba TV that occasionally interrupts for a second or two for no apparent reason. I believe the problem is in the TV not anything else. The problem may be triggered by a fluctuation in the mains voltage but its not an electricity supply or wiring problem.

 

The fact that it happens when you switch a fan or a light on may be incidental.

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No help, but I had the same issue--along with others, so had the wiring re-done in my house, same thing as before, no improvement in the television going off when fan switch is turned off. I'm not an electrician but tend to go with the shared neutral issue. Sure wish I could find a western trained electrician in the Chonburi area....the Thais I've had in just don't understand enough about electricity. I've had to explain a few things to them, of course everybody lost face when I did that....oh well.

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