I installed a new GFCI receptacle ahead of a bathroom light fixture a few days ago. All appeared to be operating normally. Today the client called and sent me a video, the light fixture now flashes continuously when she turns on the power via the light switch. I did wire this light fixture to the load side of the GFCI. The GFCI receptacle appears to still be working normally.

I will go tomorrow to check out this problem. I am thinking that I can simply rewire the lights to the line side of the GFCI. Can anyone suggest what is going on here?

 

Strange problem.
Is the light switch a dimmer type?
Otherwise could be a faulty GFCI.

Of course wiring the lights to the line side, will negate the GFCI protection to the lamp fixture.

 

No it is just a regular Leviton SPST switch with normally turn the lights on and off.

I thought that it could be a bad GFCI, however, it is still operating normally and TEST/RESET is fine.

Yes I realise it would negate the GFCI protection on the light fixture, but that was really unnecessary in the first place. Regardless, it will be my first attempt to stop the flashing lights.

In all the years I have been installing these this is the first time I have seen this problem... I have attached an animated gif demonstrating the problem...

 

Is there more than one bulb in the lamp that blinks?
Is it an LED?

 

Don’t rule out coincidence. If the light worked properly when you installed it, we only know that something has changed since. It could be either the outlet or the light itself.

Edited to add:

Post hoc ergo propter hoc (Latin: 'after this, therefore because of this') is an informal fallacy which one commits when one reasons, "Since event Y followed event X, event Y must have been caused by event X."

 

Is there more than one bulb in the lamp that blinks?
Is it an LED?

Yes all three LED bulbs blink... its like the fast blinking of a SMART Light Bulb that has lost it's network settings and you need to reassociate it with your Google Home Application

 

Whatever it is, it isn't likely to be the GFCI. I say that because the circuit through the outlet is a physical contact. It's just a switch that is opened by the device. There is no electronic component in the line between input and output. Cheap LEDs flicker with new mini split air conditioners in the house, or new direct drive washing machines. Look for that.

 

I have had several long days trying to retrofit a GFI into existing wiring that was not done the way I would have done. Worst was my bathroom, wiring went :

Power in -> main switch -> outlet -> room lamp. Physical arrangement too.

One would think replacing the outlet with a GFI would be simple... was not as the wiring from switch to lamp did not go thru the outlet clean.

So I had to NOT protect the lamp, just the outlet itself.

Oh had I remembered that when I had to replace the outlet GFI a decade later...

 

Okay, now I have egg on my face. I want to thank everyone who posted a reply to this my first post, and yes I do feel like a complete fool. I have only been installing these things for 25 years and this is the first time I have run into a problem.

So what was the problem? I was installing a GFCI receptacle with a new bathroom vanity light fixture. I have attached a pictures of the light fixture, the Wiremold surface-mount box and the assembled GFCI. Basically, I had the switched power from the old light fixture going to the LINE side of the GFCI outlet and the LOAD side was driving the light fixture. So this all seems fine, but when I went to install at the clients home I just grabbed three "LED bulbs" from my stock, forgetting I had some SMART bulbs in there. So installation day everything worked perfectly...

What happened? Well the client was showing the new lights to a neighbour and she turned them off and on and off and on and off and on. LOL, the bulb reset/pairing function, so all 3 bulbs began flashing twice each second. I mentioned this in my third reply to crutschow above: "its like the fast blinking of a SMART Light Bulb that has lost it's network settings". So thankfully, I had brought a few LED bulbs and was able to find 3 plain LED bulbs. I swapped them out and problem was solved.

But I decided to move the fixtures power feed from the LOAD side to the LINE side of the GFCI. A number of people had suggested the last thing you want is to have the lights go out when your GFCI has cut off the power and saved your life. So I just moved the neutral and live feed to the lights to the line side of the GFCI... or so I thought... LOL another 15 minutes wasted tearing that GFCI out of it's box again. Of course I had move the LINE feeds to the LOAD side. The most common error in wiring these circuits.

Well I spent 1.5 hours resolving this (I used the wrong light bulbs) problem. And yes I am humbled and embarrassed. I am glad I am my own boss, I will just pretend none of this ever happened. Thank you everyone who responded. You are all very kind.

Cheers,
Scott

 

I am glad that it was not a GFCI issue or an LED bulb issue I recently added two LED fixtures with a dimmer to dim them and a plug-in LED lamp, all at the same time. With the first dimmer the lamp dimmed perfectly, the 2 LED fixture did a good strobe-lite display. The client found that not acceptable. So I installed a dimmer "guaranteed" to work with LEDs. The plug in lamp dims perfectly, the fixtures do not dim at all.. The fixtures use what looks like small ballasts, they must be regulated current supplies. So no fix yet, I will need to create a non-regulated mains powered lower voltage DC supply. I really do not want to do that.

 

I am glad that it was not a GFCI issue or an LED bulb issue I recently added two LED fixtures with a dimmer to dim them and a plug-in LED lamp, all at the same time. With the first dimmer the lamp dimmed perfectly, the 2 LED fixture did a good strobe-lite display. The client found that not acceptable. So I installed a dimmer "guaranteed" to work with LEDs. The plug in lamp dims perfectly, the fixtures do not dim at all.. The fixtures use what looks like small ballasts, they must be regulated current supplies. So no fix yet, I will need to create a non-regulated mains powered lower voltage DC supply. I really do not want to do that.

I don't know where you are located but in the US, the National Electrical Code forbids a standard receptacle to be dimmed.