GFCI after dimmer??

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mint402

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Odd one I know.....customer has plug in outdoor lighting that is dimmable......of course it will be on a gfci outlet....he also wants to make it dimmable with a AYCL dimmer.....anybody know if the gfci will function normally under that arrangement? Would seem like the sensing/testing should be ok given that it is just doing a differential compare....but ??

Will of course test it for proper operation but curious if anybody has any experience.
Thanks,
Bruce
 
This will not function correctly as far as I know and it is also non compliant. You cannot dim a receptacle unless it is a special style rated for dimming.

They look like this

Lutron-NTR-15-DDTR-WH-2T.jpg
 
Sorry I should have listed the article

2014 Nec said:
406.15 Dimmer-Controlled Receptacles. A receptacle supplying
lighting loads shall not be connected to a dimmer
unless the plug/receptacle combination is a nonstandard
configuration type that is specifically listed and identified
for each such unique combination.
Click to expand...
 
I agree,

Can you you install a gfi breaker for the circuit ahead of the dimmer with the receptacle Dennis shows?
That would keep you in compliant.
 
I really don't know the electronics of the gfci so it may work fine on a dimmer, I just don't know. But as I said the receptacle on a dimmer is not compliant so why take a chance with the gfci on a dimmer...
 
What about putting GFCI upstream of dimmer - then use receptacle like Dennis suggests? Or is the recept that Dennis shows GFCI???
 
Dennis Alwon said:
Sorry I should have listed the article
2014 Nec 406.15 Dimmer-Controlled Receptacles. A receptacle supplying
lighting loads shall not be connected to a dimmer
unless the plug/receptacle combination is a nonstandard
configuration type that is specifically listed and identified
for each such unique combination.
Click to expand...
Click to expand...
This section has been deleted in the upcoming 2017 NEC. FYI.

The requirements remaining are in 2017 NEC 404.14(E) and the Product instructions and the Listing Requirements.
 
Dennis Alwon said:
I really don't know the electronics of the gfci so it may work fine on a dimmer, I just don't know. But as I said the receptacle on a dimmer is not compliant so why take a chance with the gfci on a dimmer...
Click to expand...

I've recently had problems with lamps that weren't even on the dimmer, I would not entertain the notion of putting a GFCI on the load side of a dimmer.
 
It has a power supply inside that control the logic circuit and requires proper line voltage. Dimmed hot is not a proper 120v.

What lamp does the outdoor fixture take? Could they use one of those funky faddish connected system lamps? Each lamp has a dimmable LED ballast that link svia WFi or to base unit then WiFi? The wall switch is left on all the time. The circuitry on internal LED ballast does all the controlling through RF command.

There would be more leeway with silliness since those would not be considered permanently installed electrical apparatus.
 
Dennis Alwon said:
This will not function correctly as far as I know and it is also non compliant. You cannot dim a receptacle unless it is a special style rated for dimming.

They look like this

Lutron-NTR-15-DDTR-WH-2T.jpg
Click to expand...

Though they may be rare in the wild, I can already see those nubs being broken off so that a standard plug can be inserted - just like people have broken off EGC pins from the cord ends for many years now when encountering a two wire receptacle.
 
The sensing aspect of a GFCI should function correctly on the output of the dimmer, however the high frequency associated with the switching might cause nuisance tripping.

As Electric-Light mentions, the GFCI itself requires power to function, and it is very unlikely that the power supply would work correctly on the output of the dimmer, IMHO it will function correctly over part of the dimming range, not function at all over other parts of the dimming range, and might let out smoke in the middle.

Using the GFCI upstream of the dimmer might function...unless the dimmer uses the EGC as a circuit conductor for its own power supply.

-Jon
 
I modified a portable 1000W quartz work light fixture by putting a toggle style dimmer in line in a Bell box with a lever cover as part of the stand, because 1000W is usually way too bright (but I got it for free). I plug it into GFCI outdoor receptacles all the time at different job sites, it has never once been an issue. If the guy wants a dimmable outdoor fixture that can plug in to a receptacle, I'd do it that way rather that put the dimmer ahead of the receptacle. The receptacle becomes more useful that way as well.
 
Jraef said:
I modified a portable 1000W quartz work light fixture by putting a toggle style dimmer in line in a Bell box with a lever cover as part of the stand, because 1000W is usually way too bright (but I got it for free). I plug it into GFCI outdoor receptacles all the time at different job sites, it has never once been an issue. If the guy wants a dimmable outdoor fixture that can plug in to a receptacle, I'd do it that way rather that put the dimmer ahead of the receptacle. The receptacle becomes more useful that way as well.
Click to expand...

You don't feed things like electronics, ballasts, etc not meant to be dimmed downstream of a dimmer. Putting a GFCI at an outlet that is upstream of the light switch or at the panel and identifying the outdoor receptacle appropriately is a far better answer than even thinking about "dimming" a GFCI. At best something lets out the smoke. At worst, GFCI could be rendered ineffective.
 
Dennis Alwon said:
This will not function correctly as far as I know and it is also non compliant. You cannot dim a receptacle unless it is a special style rated for dimming.

They look like this
Click to expand...

Could the supply be run through the GFI to a standard receptacle, the load to be dimmed plugged into that receptacle with the dimming being done downstream of that?
 
Besoeker said:
Could the supply be run through the GFI to a standard receptacle, the load to be dimmed plugged into that receptacle with the dimming being done downstream of that?
Click to expand...
Yes, to get around altering the input voltage to the GFCI, but no you must use a receptacle like Dennis posted in post #2 if you are going to "dim the receptacle" instead of a "standard receptacle".

Hope that makes sense.
 
My question is will the gfci work properly. I am sure the UL listing didn't test for that but I am curious as to why the gfci would not work.... Anyone try it and test that the gfci is working properly?
 
Dennis Alwon said:
My question is will the gfci work properly. I am sure the UL listing didn't test for that but I am curious as to why the gfci would not work.... Anyone try it and test that the gfci is working properly?
Click to expand...

A GFCI has active electronics that need to be supplied at the correct voltage and frequency, a modern dimmer changes both of those perimeters.

How far out of tolerance the supply can be? I have no idea but no doubt at some point the electronics would cut out.
 
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