# GFCI after dimmer switch



## curiousB (Jan 16, 2012)

Just had a situation that was strange. Chandelier style light fixture above soaker tub. Protected by GFCI in adjacent walk in closet (GFCI dedicated to light fixture only). Line side of GFCI ran back to a wall switch then to branch circuit power source. The switch was a slide dimmer.

The odd thing is that when dimmer was on 100% the gfci would trip and reset fine. Set the dimmer less than 50% and it would trip fine with test but wouldn't reset. Set dimmer close to zero and it would neither trip or reset. 

The fix was a pain. The gfci needed to be ahead of the dimmer switch. In other words the dimmer needed to be on load side of gfci with the fixture. The way the wires ran the power source was with the dimmer but not enough conductors to the closet gfci location.

So in the end had to cut out a three gang wall box and put in a 4 gang box and put a dead front gfci beside the dimmer switch. I then eliminated the down stream gfci and put a blank cover over that box.

I just wonder if the original electrician knew he was faking a gfci install after the dimmer and was just too lazy to make it right...

What about a chandelier style fixture above the tub. Does that have to be a wet rated fixture. It is quite high so you can't touch it standing in tub (maybe Shaquille could)..

Is it a code violation to put a dimmer (or any switch) ahead of a gfci? Or just poor common sense?


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## k_buz (Mar 22, 2012)

(D) Bathtub and Shower Areas. No parts of cord-connected
luminaires, chain-, cable-, or cord-suspended luminaires, lighting
track, pendants, or ceiling-suspended (paddle) fans shall
be located within a zone measured 900 mm (3 ft) horizontally
and 2.5 m (8 ft) vertically from the top of the bathtub rim or
shower stall threshold. This zone is all encompassing and includes
the space directly over the tub or shower stall. Luminaires
located within the actual outside dimension of the bathtub
or shower to a height of 2.5 m (8 ft) vertically from the top
of the bathtub rim or shower threshold shall be marked for
damp locations, or marked for wet locations where subject to
shower spray.


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## Speedy Petey (Feb 1, 2004)

I would think it was common sense to not dim a GFI. You say an electrician did the original install?


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## curiousB (Jan 16, 2012)

Yes home builders electrician did it this way. As built. House is only 8 years old.

Based on code reference even with gfci this is an illegal use of fixture? I went and measured, lowest point of fixture is 80" from bottom of tub, 63" from water level at overflow height.. Yikes.

Does code state no switch permitted on line side of gfci's?


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## k_buz (Mar 22, 2012)

It is completely legal to switch a GFI. However, you cannot dim a receptacle. The fixture install is violating the clearances and should never had been passed. I would also question the damp location rating.


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## curiousB (Jan 16, 2012)

k_buz said:


> It is completely legal to switch a GFI. However, you cannot dim a receptacle. The fixture install is violating the clearances and should never had been passed. I would also question the damp location rating.


Maybe a nit but permitting switching of line side of gfci renders test reset inoperable which could be confusing if switch and gfi are not near each other. Further if a dimmer is installed then it won't work properly except at 100%. That may compromise gfci operation at dimmed levels.


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## stickboy1375 (Apr 28, 2012)

Just for examples, this picture below is 100% code compliant.... No GFCI required.


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## curiousB (Jan 16, 2012)

stickboy1375 said:


> Just for examples, this picture below is 100% code compliant.... No GFCI required.


How is lower pict compliant? That seems inside keep out zone. What am I missing?


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## stickboy1375 (Apr 28, 2012)

curiousB said:


> How is lower pict compliant? That seems inside keep out zone. What am I missing?


Look at the TYPE of fixtures required to be out of the zone...


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## mpoulton (Jul 23, 2009)

k_buz said:


> It is completely legal to switch a GFI. However, you cannot dim a receptacle.


Even if it were a deadfront GFCI, you couldn't dim it - it violates the voltage ratings of the device, since it is listed to be used only at 120V. It will, in fact, not properly provide GFCI protection except when the dimmer is close to fully on.


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## mpoulton (Jul 23, 2009)

stickboy1375 said:


> Just for examples, this picture below is 100% code compliant.... No GFCI required.


I'm not so sure those sconces look damp-rated.


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## stickboy1375 (Apr 28, 2012)

mpoulton said:


> I'm not so sure those sconces look damp-rated.


I installed them, they are UL listed with a damp rated location sticker on them.


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## curiousB (Jan 16, 2012)

mpoulton said:


> Even if it were a deadfront GFCI, you couldn't dim it - it violates the voltage ratings of the device, since it is listed to be used only at 120V. It will, in fact, not properly provide GFCI protection except when the dimmer is close to fully on.


I know that is why I put in dead front gfci ahead of dimmer. Are you saying dimming on load side of gfci is not allowed?


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## Speedy Petey (Feb 1, 2004)

curiousB said:


> I know that is why I put in dead front gfci ahead of dimmer. Are you saying dimming on load side of gfci is not allowed?


NO. Dimming on the LINE side is not allowed.


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## mpoulton (Jul 23, 2009)

stickboy1375 said:


> I installed them, they are UL listed with a damp rated location sticker on them.


Wow. Are the lamps enclosed inside the fixture?


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## Speedy Petey (Feb 1, 2004)

mpoulton said:


> Wow. Are the lamps enclosed inside the fixture?


Do they need to be? :huh:


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## mpoulton (Jul 23, 2009)

Speedy Petey said:


> Do they need to be? :huh:


Not necessarily, but most damp-rated fixtures seem to be enclosed.


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