Problem with Lutron Switches

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SSDriver

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Electrician
I'm currently having some issues with the Lutron switches. I have 3 switches (just the ON/OFF, not dimmable) and they bleed 10-11v in the off position. I checked them with a low impedance meter with NO load connected. I first noticed it when some CFL bulbs would flicker every 2-4 min while off. This reminds me, I need to contact lutron. In the room that has LED bulbs there is no noticeable defect unless you check it with a meter. If you touch the wire, you do get a little zap.
 
SSDriver said:
I'm currently having some issues with the Lutron switches. I have 3 switches (just the ON/OFF, not dimmable) and they bleed 10-11v in the off position. I checked them with a low impedance meter with NO load connected. I first noticed it when some CFL bulbs would flicker every 2-4 min while off. This reminds me, I need to contact lutron. In the room that has LED bulbs there is no noticeable defect unless you check it with a meter. If you touch the wire, you do get a little zap.
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I had that issue with some Lutron ceiling fan/light controls. I noticed it because I had a non-dimmable bulb in it and it was on very dim
The light
 
The switches probably have a triac instead of a mechanical relay. Triac's leak some voltage when there is no load to shunt it. The reason CFLs blink when off is the switch leaks enough current to charge up the cap in the CFL ballast circuit and when it reaches enough voltage the light blinks which discharges the cap and restarts the cycle.
 
SSDriver said:
I spoke with lutron and they have a capacitor they recommend to use between the load wire and the neutral.
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Interesting. Is it really a capacitor, or a resistor? Or a snubber capacitor which is a film cap + series resistor in one package. CDE Quencharc is one example of such a component.
 
It is a load capacitor, at least that's what they call it. They package them with some of the RF switches that use wireless remote switches such as the Casetta and Pico. Mostly they are for LED bulbs that don't produce enough load for some dimmers to operate correctly. I use them quite often.
 
Little Bill said:
It is a load capacitor, at least that's what they call it. They package them with some of the RF switches that use wireless remote switches such as the Casetta and Pico. Mostly they are for LED bulbs that don't produce enough load for some dimmers to operate correctly. I use them quite often.
Click to expand...
interesting that they require a certain 'load'.....~RJ~
 
Little Bill said:
It is a load capacitor, at least that's what they call it. They package them with some of the RF switches that use wireless remote switches such as the Casetta and Pico. Mostly they are for LED bulbs that don't produce enough load for some dimmers to operate correctly. I use them quite often.
Click to expand...
I've installed a ton of Caseta and Pico devices, never seen one. But here it is on Amazon...


Description:
Lutron Shunt Capacitor to assist with non-neutral based digital switches in meeting minimum load requirements. The LUT-MLC comes in the package with Lutron digital switches that do not require a neutral connection. In most scenarios, it is not needed, however if the switch is wired in and it does not completely turn off the light or flashes/flickers in the off state, the LUT-MLC will need to be installed either in the switch's junction box or in the first fixture of the lighting circuit. The LUT-MLC was only designed to be used on Lutron digital switches. They should not be used on dimmers with the exception of ones rated for electronic low voltage, such as the Caseta PD-5NE. The LUT-MLC will only help with a light not turning completely off once the switch has been turned off. It will not help with other dimming issues caused by the type of light bulb, such as flashing or buzzing
 
James L said:
... The LUT-MLC was only designed to be used on Lutron digital switches. They should not be used on dimmers with the exception of ones rated for electronic low voltage, such as the Caseta PD-5NE.
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I believe they are saying not to use the capacitor on the common "forward phase" type dimmers that use a Triac. This is because the fast rising edge on the voltage waveform from such a dimmer would cause a large current spike to be drawn by a capacitor. The "reverse phase" dimmers for ELV have a transistor that open circuits at the end of each conduction period, which will cause no issue with a capacitive load.
 
romex jockey said:
interesting that they require a certain 'load'.....~RJ~
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It's not so much that they require "a certain load"; it's that they require a certain amount of low-level current through their switch to power the switch's internal electronics. These are "smart switches" designed for retrofit into switch boxes that contain no neutral for returning the current used to power the smart electronic circuitry (which is always on) within the switch. They work by passing that milliamp current out through the connected load.

If your load is an incandescent light bulb, you'll never any effect because the amount of current is insufficient to make the filament illuminate. But with some LED lights, the amount of current is just enough to make the LED glow softly. Other LED lights have internal driver circuitry that will accumulate a capacitive charge from this current and when that charge is high enough, it will discharge through the LED causing the LED to flash.
 
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