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GFCI reset causes light flicker

Posted by grandmum (My Page) on
Thu, Dec 29, 11 at 0:54

I have bathroom lights on same circuit as GFCi outlet. When I test the GFCi, on the reset, the light blink. Is that normal? I do not notice flicker or blink on those lights at any other time.


Follow-Up Postings:

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RE: GFCI reset causes light flicker

If there is some sort of load (heater, etc...) on the protected side of the GFCI this wouldn't be too surprising.


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RE: GFCI reset causes light flicker

I dont understand, please explain. Do you feel that it needs to be checked?

The only thing plugged in and working when I noticed this is a television on the same circuit. And of course the lights in the bathroom where I noticed the blink when resetting the GFI.


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RE: to add what I just tested

I tried another GFCI in another bathroom and it did not do the same thing.

When I read about light flicker it always said to check the connection. However, I only see the quick blip of the light when a turn the GFCI back on, so I am assuming its an issue with the GFCI and not a loose connection. But I am unclear... please advise.


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I understand a little better

your suggesting that I turned off and then turned on a high draw item like you mentioned heater.

This is not the case with the TV there is nothing that shuts off when I toggle the GFCI? So the TV would have no issue....

well I guess im even more confused now on why its happening.


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RE: GFCI reset causes light flicker

If there is anything on the circuit with the GFCI, then when you press the reset, a flicker wouldn't be a surprise. There's probably just a bit of a loose connection in the reset button of the GFCI. I doubt that it's a real problem, but if you're concerned, you can replace the GFCI. They're not very expensive.


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RE: GFCI reset causes light flicker

Here's another test. Push on the GFCI receptacle (not the buttons) at various points and see if the lights flicker. If they do, then most likely there's a bad connection inside that box which needs attention. Given the ugly job I've seen many homebuilders do, they may have backstabbed the through connection to the lights through the GFCI itself.


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RE: GFCI reset causes light flicker

It might be the capacitors in the TV charging that's causing the flicker.


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RE: GFCI reset causes light flicker

"...is a television on the same circuit."
Televisions (old and new) both pull a decent surge of current when they are first turned on.
The fact that the picture is not on does not eliminate the current surge the power supply pulls when power is applied to it initially.


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RE: GFCI reset causes light flicker

Thanks for the replies. Its not because of the TV as the TV does not turn on or off when the GFCI is reset. The lights and gfci outlet are both on the same circuit. Only the outlet turns off when the GFCI is toggled. I assume that the only thing that is GFCI protected on the circuit is the outlet only.


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RE: GFCI reset causes light flicker

"Its not because of the TV as the TV does not turn on or off when the GFCI is reset."

Is the TV on the same circuit?

On or off does not matter all that much.

Many new TVs are always 'on' as long as they are plugged in.

Even when you hit the remote or on/off button, a lot of the electronics are still turned on.

The only way to make them fully ff is to unplug them from the power.


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RE: GFCI reset causes light flicker

While I really don't know whether the television is downstream on the circuit or not, and playing a role here, the newest sets for the last several years are very much more energy efficient.

In order to meet US and EU Energy Star requirements they must use less than 1 watt when turned off. To perform this, they usually use two-step power supplies that use relay switching to go from standby mode to on. When off, they just use a small 5 volt supply for the IR sensor and memory functions.

Although I am not usually a fan of government intervention on consumer electronics (excluding FCC and UL), this is an area that needed to be addressed. I used to have a DishTV box that used 20 watts turned on and 20 watts "turned off" - they only turned off the LED on the front panel and actively blanked the video output.


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RE: GFCI reset causes light flicker

You know it's down stream if it goes off when you turn trip the GFCI.


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TVs

Energy Star only cares about the quiescent state. When you first apply power to the unit, it can draw a bit (for various reasons including things you were told earlier) before she settles down into standby mode.


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RE: GFCI reset causes light flicker

Standby mode it NOT the same as power up.

Capacitors must be charged and magnetic fields established when power is first applied.

It should throttle back after that, but the initial surge is not controlled by energy star.


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RE: GFCI reset causes light flicker

"You know it's down stream if it goes off when you turn trip the GFCI."

The OP indicated it is on the same circuit but not on the GFCI protected load connection. That was a very good thought about a loose connection in the GFCI outlet box that was causing an intermittent feed downstream.

Many newer flat panel televisions basically use two power supplies built into the same power supply assembly. The first is a very low wattage 5V supply for "housekeeping" functions - IR remote sensor and volatile memory. This is the only one that receives power when the set is plugged in and causes virtually no measurable current surge.

The second supply, which is relay switched from the first power supply after a power-on command, is where the rectified AC line voltage, along with surge of charging the large ufd capacitors creates a noticeable and measurable current draw.

Many countries did, and now the EU, require a mechanical switch as well to create a true off mode.

The terms off, stand-by, and on are very specific and understood in consumer electronics design.

Also, once again to meet latest EU (European Union) requirements, power factor correction must now start being built into products as well. Most mfgs choose to use active digital PFC which eliminates any large capacitors hanging on the rectified AC input and at the same time eliminate large start-up current surges. Since designs are basically done for worldwide manufacturing now, those same designs usually appear in US products too.


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RE: GFCI reset causes light flicker

Well if you want to get picky about it. There's not any big capacitors nor heavy transformer corders to worry about either in your digital TV. The power cord most likely goes through a fuse to a pair of hefty diodes that are the beginning of the modern switching power supply.


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RE: GFCI reset causes light flicker

Just to state the obvious..... you don't need to know anything about TV construction to determine if it contributing to what you see. Just unplug the thing.

If the problem only occurs when you press he reset switch, chances are, it is a problem with the switch. It could be a loose connection or it could just be that the switch is worn out. Personally, I'd spend the $15 buck on a new GFCI for peace of mind.


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RE: GFCI reset causes light flicker

"Well if you want to get picky about it. There's not any big capacitors nor heavy transformer corders to worry about either in your digital TV. "

There are still decent size capacitors in switching power supplies, and a relatively larger inductor that pulls current to create a magnetic field.

The capacitors do not have as large a voltage rating, but are still there to smooth the output of the switching supply circuit.


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