Lutron skylark s-600 p dimmer doesnt work all the time why?

That is normal with a lot of dimers. If you have LED lamps try a different brand. If tungsten give the filament time to warm up. I think you will find the dimmer it is set the longer for them to come on.

That switch says on it that it is for fluorescent lights only. I don't know if you can use compact fluorescent bulbs on that system, perhaps verify if you can or not. The switch has electronics in it and may need that ground wire to get 120 volts to operate. If you have incondescent light bulbs return and get the correct dimmer.

Older dimmer switches use rheostats to adjust the resistant loads on the switch. Since this is a mechanical operation, over time they become loose or corroded. So it sounds like this has happened to your dimmer switch and you should replace it with a more modern switch that isn't as mechanical.

It is neither - it is rated for incandescent lamps only. It sounds like someone suggested that your puck ligths are being controlled by electronic low-voltage transformers, in which case, if you wanted to stick to the Skylark family, should be an SELV-300P-WH.

If you're not sure about any of this, I suggest calling Lutron's tech support line. It's at 1-800-523-9466, they're available 24/7, and can double-check the recommendation.

This is single-pole -or- 3-way dimmer
Manual shows on following link:
http://www.lutron.com/TechnicalDocumentLibrary/0301107A.pdf

1) Manual says: The red/white wire is not used in a single-pole application. Twist a wire
nut over this wire for a single-pole application.
2) Green wire connects to bare ground wire. Or bare ground to bare ground.
3) Connect dimmer-red and dimmer-black to either insulated wire that came off of old switch

Add a comment for more free help.
Also take advantage of fixya phone service.
For a price, fixya expert speaks with you over phone while you work on dimmer or any do-it-yourself project.
We are always less expensive than a service call.

These in-wall devices stop working and need to be replaced from time to time.
There are no repair parts.
Generally dimmers don't last as long as ordinary light switch, because they are electronic instead of mechanical.

Lutron makes the widest selection of dimmers.
http://www.lutron.com/Products/StandAloneControls/Dimmers-Switches/Pages/DimmersSwitches.aspx

Use link above to identify dimmer.
For example Skylark dimmer.

Then google search for a replacement.
For example: single pole 600 watt lutron skylark dimmer
Or: 3-way 600 watt skylark dimmer
Lutron also makes 1800 watt dimmers for larger loads.

Add a comment any time if you need more help.

You can also take advantage of fixya phone service.
Fixya expert will talk with you via phone for a price.

http://www.lutron.com/Products/StandAloneControls/Dimmers-Switches/Pages/DimmersSwitches.aspx

Lutron shows widest selection of dimmers.
The wattages you posted are standard for multiple dimmers.

Once you identify type of dimmer, add a comment and say if dimmer is single-pole or 3-way.
A 3-way dimmer would be in a hallway, where more than 1 device controls same lights.
Single pole is where one device controls lights.

If I know what dimmer you have, I can search for the product and add another comment.

Or search for yourself:
For example, let's say you have 3-way Skylark dimmer.
Do a google search for 3-way skylark dimmer:
http://www.google.com/search?q=3-way+skylark+dimmer&ie=u
Or 3-way rotary dimmer, etc.

If information above doesn't help, then take advantage of fixya phone service.
Fixya expert can talk with you over the phone for a price.

Yes, it sounds like your input power wire got mixed up with one of the output wires.

You will need to return the 3-way dimmer and get a single pole dimmer, as the Lutron Skylark series is suspectible to failure if connected to a live circuit first, or misconnected at intial installation. As an electrician, I ceased using these dimmers years ago, due to the rash of call-backs by customers and went with Leviton togglers and have had excellent results.

If you purchased it at a 'big box' store, they will accept the return as a defective item, as they have national agreements with their suppliers to accept customer returns. Just tell them it didn't work and you want a store credit, you can then purchase the lower priced single pole dimmer you need and save some money in the process too.

Hope you find this Very Helpful - best regards!

This video from the Lutron site shows the Diva switch but it is the video for the Skylark single pole switch also. It makes no mention of one wire being a larger gauge and does not differentiate which wire connects to line power and which to load. I do not think the wire gauge makes any difference.