# Me scratching my head.........



## macmikeman (Jan 23, 2007)

So I wired up this dining room fan/light in a house such that the fan was controlled at a single point by a fan speed control switch, and the fan light I put on a three way switch system with one end controlled by a dimmer. There are two open entry ends to this dining room , so I wanted the light to be able to be controlled from each end (off and on) and dimmed from the side closest to the kitchen. 

So here is the problem . After installing the fan/light which has led lamps , the led light will stay on slightly no matter which way the plain Jane three way switch is turned. Somehow power is slightly coming thru the system but that doesn't compute with me. I figure it must be the dimmer, but it doesn't compute . The vanilla three way switch should kill all power , I could see the dimmer bleeding a bit but that other end of the three way should not allow it past. 

Anyway , I am going to remove the dimmer and replace so that both switches are just three ways, but I don't understand how this could be happening. Didn't meter anything yet, but I figure must be some potential between neutral and ground maybe that slightly powers the led's? At night when all other lights are off there is a tiny slight glow when the light is turned off. It's weird.


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## Dennis Alwon (May 9, 2009)

Not an uncommo9n situation with dimmers... I can only guess why this happens but did you try a different brand LED bulb? I am pretty sure it has something to do with the dimmer and the neutral.


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## Drsparky14 (Oct 22, 2016)

Try a magnetic dimmer


Sent from my iPhone using Tapatalk


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## macmikeman (Jan 23, 2007)

Dennis Alwon said:


> Not an uncommo9n situation with dimmers... I can only guess why this happens but did you try a different brand LED bulb? I am pretty sure it has something to do with the dimmer and the neutral.


The built in led's kind . The thing probably needs an electronic dimmer , but I am not coughing up a hundred smacker's for one. I told the nice lady she doesn't need a dimmer and she agreed with me. So the light is going to go on and off only when I remove the dimmer and replace it with a three way. 

Still I am curious as to what is happening to make a light go on (dimly) when the circuit is cut. One thing I forgot to check was turning the fan motor off and then checking. Maybe some capacitive bleed over from the wiring in the stem.


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## RePhase277 (Feb 5, 2008)

There is capacitance between the conductors. Sometimes there's enough capacitive current flow to dimly light the LEDs. As an experiment, when the switch is off and the lights are glowing, short the hot and neutral and see if it goes away.

The LEDs in my hallway did the same thing, so I put three 100 kohm resistors across the switchleg and neutral at the switch box and that cured it.


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## Atheist1 (Oct 26, 2017)

It is not uncommon and is easily rectified. Install a blocking diode on the conductor feeding the LED circuit, it will prevent backfeed.


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## macmikeman (Jan 23, 2007)

Atheist1 said:


> It is not uncommon and is easily rectified. Install a blocking diode on the conductor feeding the LED circuit, it will prevent backfeed.



So will flipping a three way switch to the other side........... But that didn't stop the led light from lighting albeit ever so slightly...


I'm going with RePhase's explanation. It makes the most sense to me.


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## farmantenna (Nov 22, 2012)

RePhase277 said:


> There is capacitance between the conductors. Sometimes there's enough capacitive current flow to dimly light the LEDs. As an experiment, when the switch is off and the lights are glowing, short the hot and neutral and see if it goes away.
> 
> The LEDs in my hallway did the same thing, so I put three 100 kohm resistors across the switchleg and neutral at the switch box and that cured it.


where can we get resistors and diodes quickly now that most Radio Shacks are closed?

I wanted to try something like your suggestion but didn't want to mail order


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## telsa (May 22, 2015)

farmantenna said:


> where can we get resistors and diodes quickly now that most Radio Shacks are closed?
> 
> I wanted to try something like your suggestion but didn't want to mail order


Ah...

You see the downside of our Internet age.

Amazon is destroying brick & mortar distribution.

See if Fry's has a store in your burg.


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## Haley (Oct 3, 2017)

juice does funny things


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## Southeast Power (Jan 18, 2009)

farmantenna said:


> where can we get resistors and diodes quickly now that most Radio Shacks are closed?
> 
> I wanted to try something like your suggestion but didn't want to mail order


I googled electronic parts near me and found an old 1960s looking electronics store with two local branches that has been doing very well since Radio Shack closed. 
They had every thing I needed as far as resisters and diodes.
I was very happy to find them.
Im sure there are plenty of them still out there.


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## Southeast Power (Jan 18, 2009)

Drsparky14 said:


> Try a magnetic dimmer
> 
> 
> Sent from my iPhone using Tapatalk


Ive been hit with a dimmer that was turned "off" 
One of the guys at the supply house near us, a CED tries out different dimmers on LEDs and swears that the cheapest crap dimmer they have works the best.


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## B-Nabs (Jun 4, 2014)

What kind of dimmer is it?

I've found that dimmers that have lights of any kind in them (indicating or locating), and also digital dimmers (like Lutron Maestros) bleed a bit of current to run those things, and if there is too small an LED load connected to it, the LEDs tend to glow. As RePhase stated, this is solved by adding resistance. Lutron even makes a module for this purpose, meaning it's listed and not just some home brewed thing. 

Sent from my SM-G920W8 using Tapatalk


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## Southeast Power (Jan 18, 2009)

IC Supply
Address: 120 Sand Island Access Rd, Honolulu, HI 96819
Hours: Open today · 10AM–2PM
Phone: (808) 839-1966

Looks like the same kind of place. 

https://www.google.com/maps/uv?hl=e...ved=0ahUKEwjm8dTQqZTXAhWJWCYKHVa1As8QoioIdjAK


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## bill39 (Sep 4, 2009)

Atheist1 said:


> It is not uncommon and is easily rectified. Install a blocking diode on the conductor feeding the LED circuit, it will prevent backfeed.


That may work but won’t the diode need to be rated for at least 15 amps, assuming that is the rating of the CB?

Sounds like a fire just waiting to happen.


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## Shaneyj (Mar 21, 2017)

macmikeman said:


> So I wired up this dining room fan/light in a house such that the fan was controlled at a single point by a fan speed control switch, and the fan light I put on a three way switch system with one end controlled by a dimmer. There are two open entry ends to this dining room , so I wanted the light to be able to be controlled from each end (off and on) and dimmed from the side closest to the kitchen.
> 
> So here is the problem . After installing the fan/light which has led lamps , the led light will stay on slightly no matter which way the plain Jane three way switch is turned. Somehow power is slightly coming thru the system but that doesn't compute with me. I figure it must be the dimmer, but it doesn't compute . The vanilla three way switch should kill all power , I could see the dimmer bleeding a bit but that other end of the three way should not allow it past.
> 
> Anyway , I am going to remove the dimmer and replace so that both switches are just three ways, but I don't understand how this could be happening. Didn't meter anything yet, but I figure must be some potential between neutral and ground maybe that slightly powers the led's? At night when all other lights are off there is a tiny slight glow when the light is turned off. It's weird.


I had this issue with a Lutron dimmer. If that's what you're using search LUTMLC. 

It works with other brands too... 

Same thing as a resistor as mentioned already. 


Sent from my HTC6545LVW using Tapatalk


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## A Little Short (Nov 11, 2010)

Shaneyj said:


> I had this issue with a Lutron dimmer. If that's what you're using search LUTMLC.
> 
> It works with other brands too...
> 
> ...


Those are actually capacitors. The MLC stands for - minimum load capacitor
I have several of them as Lutron ships them with the wireless switches that I use.

You can make one out of film capacitors of between .5 and 1.0 Mf.
Many LED lights don't have enough load for the dimmer to work so you have to add a "load" to get them to work correctly.


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## macmikeman (Jan 23, 2007)

Southeast Power said:


> IC Supply
> Address: 120 Sand Island Access Rd, Honolulu, HI 96819
> Hours: Open today · 10AM–2PM
> Phone: (808) 839-1966
> ...



I go in there all the time. Also Honolulu Electronics store.


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## MechanicalDVR (Dec 29, 2007)

macmikeman said:


> So will flipping a three way switch to the other side........... But that didn't stop the led light from lighting albeit ever so slightly...
> 
> 
> *I'm going with RePhase's explanation.* It makes the most sense to me.


See, ya just had to ask a real electrician! :whistling2:






:laughing::laughing::laughing:

Couldn't resist! :no:


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## MechanicalDVR (Dec 29, 2007)

Haley said:


> juice does funny things


Especially in humans!:whistling2:


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## macmikeman (Jan 23, 2007)

MechanicalDVR said:


> See, ya just had to ask a real electrician! :whistling2:
> 
> 
> 
> ...



It's precisely why I didn't ask you ..........

But yes, RePhase is an extremely knowledgeable sparky and I recognize that .....


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## Shaneyj (Mar 21, 2017)

A Little Short said:


> Those are actually capacitors. The MLC stands for - minimum load capacitor
> I have several of them as Lutron ships them with the wireless switches that I use.
> 
> You can make one out of film capacitors of between .5 and 1.0 Mf.
> Many LED lights don't have enough load for the dimmer to work so you have to add a "load" to get them to work correctly.


I had to think about this... 
My first intuition was that as the cap discharges, it would still cause the leds to glow. 
Does the cap absorb the current without the heating effect a resistor would have? 

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## MechanicalDVR (Dec 29, 2007)

macmikeman said:


> It's precisely why I didn't ask you ..........
> 
> But yes, RePhase is an extremely knowledgeable sparky and I recognize that .....


Ha ha ha!

Yeah boy, he does come across as very experienced.

There have been several posts here about the 'always on dimly' problem you had here, surprised to see you haven't seen them already.


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## macmikeman (Jan 23, 2007)

MechanicalDVR said:


> Ha ha ha!
> 
> Yeah boy, he does come across as very experienced.
> 
> There have been several posts here about the 'always on dimly' problem you had here, surprised to see you haven't seen them already.



But not very many (any?) ever delved into the three way side of things. Draw out the circuit and you will see my ??? . Light is slightly on? Flip the three way, that will send the power down the other traveler and yet I still see the glow, so yea, I never read anything directly about a three way dimmer doing that....


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## MechanicalDVR (Dec 29, 2007)

macmikeman said:


> But not very many (any?) ever delved into the three way side of things. Draw out the circuit and you will see my ??? . Light is slightly on? Flip the three way, that will send the power down the other traveler and yet I still see the glow, so yea, I never read anything directly about a three way dimmer doing that....


I thought I read one here were the guy tried moving the 3 way switch and adding a bleed resistor maybe in was some where else I read it.

I've only replaced a few cans with LED and haven't had these problems yet.


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## HackWork (Oct 2, 2009)

Mikey, are you going back? If so, I demand you pull out the non-dimmer 3-way, use it to shut off the light, and then remove the dead traveler from the screw and see if that shuts it off. That will prove that the inductance from the 2 travelers sitting in the cable together is enough to light the LED. 

I too have never seen this before in this situation of a switch totally killing the power but the LED still lighting. Usually there is something solid for power to bleed thru.


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## macmikeman (Jan 23, 2007)

HackWork said:


> Mikey, are you going back? If so, I demand you pull out the non-dimmer 3-way, use it to shut off the light, and then remove the dead traveler from the screw and see if that shuts it off. That will prove that the inductance from the 2 travelers sitting in the cable together is enough to light the LED.
> 
> I too have never seen this before in this situation of a switch totally killing the power but the LED still lighting. Usually there is something solid for power to bleed thru.


At some point in the next day or two your majesty, soon as the granite countertops are installed.


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## HackWork (Oct 2, 2009)

macmikeman said:


> At some point in the next day or two *your majesty*, soon as the granite countertops are installed.


Are you sassing me?


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## A Little Short (Nov 11, 2010)

HackWork said:


> Are you sassing me?


Never thought I would hear someone from New Jersey (or anywhere up north) say "sassing"!:no:

That's what my Mama use to say to me, thought it was a Southern thang!


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## MechanicalDVR (Dec 29, 2007)

A Little Short said:


> Never thought I would hear someone from New Jersey (or anywhere up north) say "sassing"!:no:
> 
> That's what my Mama use to say to me, thought it was a Southern thang!


Well dang man Denny's in NJ even has grits! 

Now if they only had scrapple and eggs.........:jester:


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## macmikeman (Jan 23, 2007)

No sassiry whatsoever, just a mistake not to use Caps due to my fingers not working so well in the cold cold chilly morning darkness.


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## MechanicalDVR (Dec 29, 2007)

macmikeman said:


> No sassiry whatsoever, just a mistake not to use Caps due to my fingers not working so well in the cold cold chilly morning darkness.


Just curious, what is the "cold cold chilly" temp on your island?


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## macmikeman (Jan 23, 2007)

MechanicalDVR said:


> Just curious, what is the "cold cold chilly" temp on your island?


70 degrees


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## macmikeman (Jan 23, 2007)

Went over there today. Put in a standard 3way. Problem solved 100%.


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