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I have a bunch of outdoor outlets which are all connected to a single GFCI and controlled by a standard light switch inside the house.

I recently replaced the standard light switch with a lutron caseta smart switch (which requires a neutral). I used the same neutral that connects to the GFCI to connect the smart switch. Other than that the wiring is the same as before.

Everything looked like it worked fine but ever since I did this, the GFCI seems to be tripped about once per day.

The outlets are just for some LED landscape lighting.

Did I wire this incorrectly/how can I resolve the GFCI tripping every now and then?

Edit: The GFCI seems to trip every time I turn the smart switch OFF.

Not sure how helpful the images will be as there is a lot of other wiring for other unrelated lights/switches going through the same places. Images

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    Can you describe the actual cable layout? Does power go to the GFCI and that has a switch loop to the switch? And you added a new cable to the switch to bring over the neutral? That would be a correct way of doing it. If it's some other arrangement please help by describing it. If power goes first to the switch, well, then you'd have a neutral so that's not it.
    – jay613
    Oct 8 '21 at 17:51
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    Waitaminute..."Except the neutral is going to the GFCI first and then from the GFCI to the switch." If the power goes from panel -> switch, why is the neutral going to the GFCI then the switch? Do you have conduit and someone got creative with the wiring?
    – FreeMan
    Oct 8 '21 at 17:52
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    Can you upload pictures (without disconnecting any wires) showing how everything connects to the switch and the GFCI? Oct 8 '21 at 18:11
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    If the wiring goes panel>switch>GFCI, then there's no reason for there to have not been a neutral at the switch. It may not have connected to the switch, but it should have been present in the box. Please do open the switch & GFCI, pull them out of their boxes without disconnecting any wiring and provide pics. That will really help everyone determine what's going on here.
    – FreeMan
    Oct 8 '21 at 18:13
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    @FreeMan you're right - it's definitely going from the panel to the GFCI first - I'm just not clear what exactly happens with the wires at the GFCI (I was initially thinking the GFCI is just being bypassed and the hot wire continues over to the switch). I will take some photos and upload when I get the chance today
    – user142469
    Oct 8 '21 at 18:26
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GFCIs don't like to be switched, so it makes perfect sense to put the switch on the protected side of the GFCI.

However, since the smart-switch is drawing its supply hot from the protected side of the GFCI, it must also draw its supply neutral from the protected side.

If it tries to take neutral from the unprotected side of the GFCI, that means it is creating a current imbalance - the switch's own hot current is coming through the GFCI but its neutral is not. The GFCI will trip at 5 milliamps (0.6 watts) of current imbalance. I could easily see a smart-switch NOT drawing that most of the time, but drawing it momentarily on occasion, e.g. when broadcasting to find a WiFi connection.

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Your current setup is:

  • panel -> switch -> GFCI/receptacle -> other receptacles

That should work just fine. However, some GFCI units do not handle power cycles very well. While that should be no different from with the previous non-smart switch, there may be something different about the way the smart switch cycles. There also shouldn't be any effect from the switch constantly using power (a very small amount) to run its own circuitry, as long as hot & neutral are on the same side of the GFCI ("Line" or "Load").

All that being said, if practical, I would change the setup to:

  • panel -> GFCI/receptacle -> switch -> other receptacles

That would let the GFCI stay on all the time, eliminating one possible source of the problem. It would also (for better or worse, depending on your usage) give you a protected-but-unswitched receptacle.

Of course, if the switch is not near the GFCI then this may not be practical. But based on the original switch not using neutral and the new switch using neutral from the GFCI, that should mean that everything is all in one big box and then easy enough to move the switch from Line to Load. On the other hand, if neutral is being pulled back, by itself, from the GFCI to the switch then there are likely other problems.

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  • I think the switch controlling the GFCI is the desired function.
    – jay613
    Oct 8 '21 at 17:51
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    Your answer has just been partially invalidated by a comment from the OP. He's clarified that your "change to" suggestion is actually what he's got. I'd hold off until the promised pics show up before making any edits.
    – FreeMan
    Oct 8 '21 at 18:28
  • @FreeMan I've updated the post with some photos/more info
    – user142469
    Oct 8 '21 at 19:18
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Another thing to consider is that GFCI's are notoriously finicky, and become more so with age. If you have a spare unit around, I would swap them out, and see if the problem continues.

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