Can I put R40 bulbs in my R30 cans?

June 5, 2008 7:38 AM

Can I put R40 bulbs in my R30 cans?

My recessed cans say R30, but I don't really like the way R30s sit in them -- they look too small for the can, and they sit so far down in the can that they just cast a cone of light like a spotlight. (I've adjusted them to not sit so deep, but this required cutting the baffle springs shorter, they look more awkward, and they're still arguably too deep.) R40s look better in the cans (to me, at least), even when adjusted to poke out of the can a bit, where they make a world of difference in the ambient light of the room.

My only worry is that I've never seen anything about using R40 bulbs in R30 fixtures. I've seen it claimed that they physically won't fit (which they do) but nothing about risk of fire or damage. I'm hoping that in our litigious world such a risk would result in some sort of contraindication on the label of the bulb or the can, of which I have found none. But I'd prefer to make sure before starting to migrate my lighting.

(FYI, these are standard Halo IC remodel cans.)

posted by bjrubble to home & garden (6 comments total)

The housing should only give you a rough idea of what type of lamp you can put in there. The specifics come from the trim (the reflector and flange that sit within the housing). There's usually a variety of lamps you can put in any given trim, but if it's not on the list, I wouldn't do it. What you're probably doing is trapping heat and violating the building safety codes, since it's only listed for certain lamps at particular wattages.

What you can do that's totally safe is find out the Halo part number of your trim and look on the Cooper lighting site for alternate lamps you might like, or find the part number of your housing and find alternate trims you could get to make the fixture look and perform the way you want it to. When you look up the cut sheet for a housing like this one, there's a list below it of all the available trim cut sheets. Replacing a trim is easy, it just pops right in the housing. Take a look at the spec for this (pdf) remodeler that's similar to the one that you have. On the second page you can see all the trims and lamps that you can use with it. Maybe the eyeball trim pointed down is the look you want, or maybe you just want to use the basic reflector trim that you've probably got and try a 75w PAR30 long neck lamp. That would give you a little more punch and the abililty to pick your beam spread so they don't look so spotty.

Best of luck.
posted by Thin Lizzy at 8:33 AM on June 5, 2008

I believe R40 and R30 lights operate off of a ballast integrated with the fixture, rather than a ballast contained in the base of the bulb. The ballast is a device that limits current flow in fluorescent lamps. Mismatching lamps and ballasts can have detrimental effects including overheating of the ballast and shortened lamp life. Find out whether the ballast is integrated with the fixture, requiring that you continue using the R30s, or whether the ballast is contained in the base of the bulb, allowing you to use R40s, keeping in mind Thin Lizzy's response above. Apologies if this info is useless; I'm applying my general knowledge of fluorescent lighting to a specific situation I'm not familiar with.
posted by Derive the Hamiltonian of... at 9:15 AM on June 5, 2008

Oh, right, I should mention that HID (metal halide, etc...) lamps also need ballasts. Your fixtures are either HID or fluorescent, I'm assuming. I guess you could also be using old incandescent bulbs. If so, consider upgrading; the energy savings will pay back the cost within two or three years.
posted by Derive the Hamiltonian of... at 9:28 AM on June 5, 2008

Derive, the fluorescent R30/40 lamps I know of are self-ballasted since they're meant to be used as replacements for incandescents that are the same size and shape. The most basic Halo remodeler housing is an incandescent downlight so I went off that. However, you bring up a good point since we don't know too much about the fixture. Bjrubble- if you need more help, feel free to post the part numbers and maybe we think up other solutions.
posted by Thin Lizzy at 9:35 AM on June 5, 2008

Thanks for the links, Thin Lizzy. I'm at work now so I can't check, but I'm guessing (hoping?) I have the H7 housings (since R40 bulbs definitely fit in them) but probably the 310 or 312 baffles, which I guess I'd need to replace.

These are incandescents -- I have CFL bulbs in a few spots, but between the warm-up time and poor dimmability I've found them to be pretty awful. (Not to mention they've almost all failed much more quickly than incandescents.) At this point I've resigned myself to just being more stingy with the light switch and waiting for LEDs to mature.
posted by bjrubble at 12:30 PM on June 5, 2008

Agreed, fluorescents are pretty heinous for residential lighting. Also, not nearly enough people recycle the bulbs properly so while they're saving energy, they're putting mercury into the environment.

Anyway, if you're looking for a place to buy lighting fixtures by the part, I'd recommend Lightology. They have nice people working there that will help you figure out what parts can go together if you're unsure about what you're seeing on the cut sheet (and I have no connection to them, for the record).
posted by Thin Lizzy at 8:42 PM on June 5, 2008