ra2

[starlight]

Does the RA2 require a specific led lamp to be used in a mr16 fixture. Thinking of changing from a 50w halogen to 5 or 8w lamp

[Bailey]

I've used the RRD-10ND (10w minimum load) or RRD-6NA (5w minimum load). May have to lock. The 6NA into forward phase. Your are dimming the magnetic transformer first. If you are using the RRD-6D, then the minimum load is 50w, and you may have poor performance without a neutral wire dimmer.

[beotownsend]

Use one of the lamps that Lutron has tested. I have also yet to come across an LED that will function without a neutral; I don't know the exact science behind why, but it seems to be extremely consistent.

A few notes:
-They don't test hybrids for LEDs; however in a lot of scenarios, they perform similarly to the equivalent of what would be a 450-Watt 10ND (connect the neutral up). You will want to make sure the LED can be dimmed in Forward Phase if using a hybrid as the dimmer. If the info isn't there, e-mail the LED division; I've found that in some cases they have more info on specific lamps than what is published. The dimming range can also be a little wonky with Hybrids, and flickering can be common as well at some ranges. Be prepared to do some experimenting with Hybrids.

-Phase, in-rush of current, etc: I have a project where the entire house is using a particular 15W Par30 lamp. In Forward Phase, Lutron tested them to present a 100W load to the dimmer (this is very common with LED lamps). In a few locations, this would have presented a big problem as there are 12-15 Lamps on some switch legs; which would be equal to 12-1500 Watts. However, in Reverse Phase, they presented their actual wattage to the Dimmer; 15 Watts. This meant I was able to use 6NA dimmers all over the place, and lock them in Reverse.

-In general, if you are designing a new system, check to make sure there are neutrals in the switch box (most of the time, there are, but just make sure). If there are, spec the system out with RRD-6NA or 10ND dimmers, I think you will probably find the most future-proofing qualities in the 6NA though (Electronic Low Voltage compatibility, Reverse Phase Dimmability, and Lowest Minimum Load). Again, plan for both the present and the future in respect to wattage per switch leg; de-rating due to ganging of the dimmers in the box. Yes, these two dimmers are $200 vs $150 for the RRD-6D MSRP, but I'd highly recommend making this cost a non-negotiable: If you start off with Inc/Halogen Lamps, but later decide, either by choice or necessity to switch to LEDs, you would most likely be looking at replacing every single RRD-6D dimmer in the house for compatibility.