Certainly an issue with all cans that could use a good answer. Unfortunately, we are most often left to our own thinking for guidance. Here are my thoughts.
If it is possible to re-install a bulb with a higher wattage, then the higher wattage rules must remain in place along with the wattage warning. If the modification is basically permanent, (no Edison socket), then the new bulb potential wattage can be considered. Remember, I'm not the authority, these are just thoughts and here is the last sentence on one of Cree's warranty statements:
"Any changes or modifications not expressly approved by the party responsible for compliance could void the user’s authority to operate the equipment." This was from a PDF under Vantage Controls.com from this search: http://www.google.com/#q=Cree+CR6+insert&hl=en&prmd=imvns&a...
Exactly what that means I couldn't say, but there are two authorities I look to, local AHJ, and UL. I didn't see any reference to UL, but if your packaging has such that would be good. As for the local AHJ, they rule and should always be contacted when looking for approval not specifically granted elsewhere.
As for boxing any can light, it is often discussed, but I have never seen a universally approved approach that would be accepted by all authorities. Lacking specific UL approval or someone else's signature on the dotted line to take the responsibility off of your shoulders, I would not box, but replace with a new AT/IC can.
i bought severa of the Cree CR6 bulbs and have put soem in my own home as substitute bulbs in AT/IC fixtures. They have been in for at elast 5 years now. before we put these in the fixtures had halogenbulbs in them. we sprayed the fixtures with open cell foam from the attic when we first installed them in 1996. so far no problems with the halogens or the LED's. not scientific, but factual.
when i told my supplier this, he said Cree does not reccomend this, and will not warantee bulbs installed this way. i have since been using TenMat domes on recessed lights, then spraying foam on the domes. we had one failure where the fixture had an incondescent bulb with the adjustable 'eyeball' trim ring. in that case airlfow is restricted by the trim ring and the bulbs overheated. the fixtures shut off. i replaced the incandescents with LED screw in bulbs and all is well.
in my case, we are specifying creating an airspace in the attic around any recessed fixture, then using spray foam to seal the outer surface of that space.
Hi Pat, although my post above kind of says not to box, I also compare boxing to installing a can in a first floor ceiling or in a drop area over a kitchen sink. In those cases, the can is still enclosed, but in a cavity that provides more area to dissipate the heat. Since I have seen no restrictions for cans in a joist cavity, I would assume a similar generous space with a box should be acceptable. At least this is the argument I use when talking to local code officials, if one is ok why not the other.
Sorry about all the typo's. not my forte` check with TenMat on this, but those covers are made for this application. they are made of rock wool, so they will not burn and are good protection for the foam. they are also easily installed.
Typo's are certainly not an issue in these days.
The key to any cover is having had UL test that specific light with that cover or possibly having UL approve that cover for any and all lights, which I don't think they would do. One cover I looked at had a list of several cans they had tested it with and it was thus approved for those and only those cans. In any event, I haven't heard of this being an issue, but would not want to be the last one in line when they were looking to blame someone.