Replacing single pole switch with smart switch

[beachhouse]

Hi,

While fixing my pool light, and decided to upgrade to a smart switch.
Currently, I have is an old 2-gang outdoor metal box containing:
- A GFCI receptacle
- A Single-pole switch for the pool light

The pool light gets power from the LOAD side of the GFCI (note that I omitted the ground wires in the picture).



The smart switch I purchased requires a neutral wire.
So, I would need two neutral wires: one for the smart switch, and one for the pool light.

Where do I get the second neutral wire?

Thanks,
Fabio

 

[Poolbreh]

Can you show the smart switch wiring diagram?

 

[Newdude]

Pull the neutral that goes to the light. Add a short piece of wire from the load side of the GFCI and pig tail the 3

 

[beachhouse]

Pull the neutral that goes to the light. Add a short piece of wire from the load side of the GFCI and pig tail the 3

Thanks! That's what I thought, but I didn't know if it was allowed for the smart switch and the pool light to "share" the same neutral wire from the GFCI.
I'll work on it over the weekend and report back.

As a fun note: this is what I am starting with. The metal box with the switch was installed many years ago, and it got partially buried underground. Nobody knew where the pool light switch was. I noticed the box by chance under a big plant, after searching for a year. The old GFCI and the switch were completely rusted, so I'll have to replace everything, including the metal box. The good thing is that I get 120V, so the wiring is still fine.

 

[Newdude]

I noticed the box by chance under a big plant, after searching for a year.

I cut mine down 3 months after moving in and found it by accident. I remember the great mystery last year. Thanks fot the closure.

 

[1poolman1]

Use the line neutral. If you use the GFCI neutral it can cause a tripping problem.

 

[beachhouse]

Use the line neutral. If you use the GFCI neutral it can cause a tripping problem.

Wouldn't that be unsafe, as the switch would not be protected by the GFCI?

 

[1poolman1]

Wouldn't that be unsafe, as the switch would not be protected by the GFCI?

Only way to have the switch in the GFCI circuit is to bring the line into the GFCI first and then into the switch. Or put in a ground fault circuit breaker in your panel to feed the switch and eliminate the GFCI device. You're not protecting the switch; you're protecting the people.

 

[beachhouse]

Only way to have the switch in the GFCI circuit is to bring the line into the GFCI first and then into the switch. Or put in a ground fault circuit breaker in your panel to feed the switch and eliminate the GFCI device. You're not protecting the switch; you're protecting the people.

If I understood correctly, this is the wiring you are proposing, right? (ground wires omitted).

 

[1poolman1]

Yes.

 

[beachhouse]

Yes.

Thanks! Out of curiosity (and for the sake of learning): what would cause the GFCI to trip if I used the LOAD neutral instead of the LINE neutral for the smart switch?

 

[1poolman1]

GFCI would sense an unbalanced load.

 

[beachhouse]

Thanks @1poolman1 !

I just went to purchase a metal box and a GFCI and I got the opposite advice from the electrician at the store, i.e. they recommend using the load-side neutral for the smart switch.
I tried to do my due diligence, but I am still confused. What I understood is that a GFCI trips when there is an imbalance between the current on the hot vs. the neutral.
If I connect the smart switch to the hot and neutral on the LOAD side of the GFCI, how would that create an imbalance? Wouldn't the circuit still be balanced?

Sorry if I am missing anything obvious!

 

[Newdude]

Sorry if I am missing anything obvious!

Nope. The radio receiver 'switch' shouldn't cause any imbalance. But they are cheapo electronics and it may cause too much electrical noise / interference for the GFCI causing occasional phantom trips. It also might not.

Use the load side of the GFCI. If it becomes an issue you can always revisit it later.

 

[SoCalTex]

For clarity - can you post the image of the wiring diagram showing the successful and proper GFCI protected smart switch?
I lost track of if the Neutral from the switch pigtails to the Line or Load side.

 

[ajw22]

If the hot wire is coming from the LOAD side of the GFCI then all neutrals downstream need to go back to the LOAD side neutral.

That is both the smart switch being powered by the hot line and the light downstream.

 

[SoCalTex]

So, like this? Thank you!

 

[ajw22]

So, like this? Thank you!
View attachment 432875

Yes.

 

[beachhouse]

Thank you all for your help!

I connected the smart switch to the LOAD side of the GFCI (both hot and neutral), end everything is working great so far!
After probably more than a decade, the pool light is on again
And I finally have an outlet close to the pool, for the Dolphin.

Next step is to replace the 10-year-old 300W bulb with a led bulb, but I am happy so far!