Safety Advice -- Homemade Light Fixture

andersonEE

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I'm planning on building a light fixture for my hallway (in my house) with 6 XR-E R2's powered by this driver from DX. Since it would be fairly low power, I'd like to leave it on 24/7 as a security light.
Assuming I have proper heatsinking and heat won't be an issue, how safe is it to use a driver like this? It obviously doesn't have UL listing.
It will be mounted pretty close to a smoke detector but is there anything else I can do to make it safer (fusing, etc.).
My fear is that my house will burn down when I'm away or worse...while I'm sleeping.:tired::oops:

Thanks!
 

andersonEE

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If this should be moved to "fixed lighting" could someone please do that?

Thanks...and sorry.
 

Mr Happy

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This perhaps is "electronics", although not "flashlight"...?

In any case, what I would do is mount the driver inside a metal enclosure on insulated supports and provide a very low amp fuse on the mains supply side.

There is a good possibility that the driver will not last a long time when powered on a 24/7 basis, but you will only find that out by trying...
 

andersonEE

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I like the idea of a metal enclosure. I would probably use ceramic epoxy to secure the driver in the enclosure though. Any good ideas on where to get the metal enclosure. It would need to be pretty thin because I'm trying to make a low profile light.
 

DIWdiver

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I'm planning on building a light fixture for my hallway (in my house) with 6 XR-E R2's powered by this driver from DX. Since it would be fairly low power, I'd like to leave it on 24/7 as a security light.
Assuming I have proper heatsinking and heat won't be an issue, how safe is it to use a driver like this? It obviously doesn't have UL listing.
It will be mounted pretty close to a smoke detector but is there anything else I can do to make it safer (fusing, etc.).
My fear is that my house will burn down when I'm away or worse...while I'm sleeping.:tired::oops:

Thanks!

I think you are right to be concerned. The listing and reviews don't indicate it meets UL, CSA, CE or other safety regulations. If it really doesn't, it probably does not have the necessary safety features to make one comfortable running it unattended.

Mounting it in a metal box would help a lot. You want to make sure the box has no holes at the bottom that could let sparks or burning debris fall out. There are many choices at the big electronics houses - Digikey, Mouser, Newark in the US, Farnell and RS in the EU (that I know of), plus others.

D
 

OldNick

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Just my 0.02. If you mount it in a metal box the heat issues may well come back again.Torches are usually made of quite think aluminium, have fins often and need this if the LEDs are going to be driven at all hard. They can still get quite warm

Once the heatsink has heated up, what matter is how fast it can get the heat to air. If the air in the metal box warms up, you could get heat issues again.

Everything depends on how hard you are going to drive the light and the size of the box for releasing heat.

As I say, just a thought.

AH! I see you are running them at 320mA, so not too bad.
 

purduephotog

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I'm planning on building a light fixture for my hallway (in my house) with 6 XR-E R2's powered by this driver from DX. Since it would be fairly low power, I'd like to leave it on 24/7 as a security light.
Assuming I have proper heatsinking and heat won't be an issue, how safe is it to use a driver like this? It obviously doesn't have UL listing.
It will be mounted pretty close to a smoke detector but is there anything else I can do to make it safer (fusing, etc.).
My fear is that my house will burn down when I'm away or worse...while I'm sleeping.:tired::oops:

Thanks!

Fuse it.

I've got 5 of the drivers and have experimented with them- they don't match that photo exactly, but for the most part they work well. See if your unit has a viper 222a chip- that's got good thermal protection and overload reset.

I'm not saying do it, but I'm saying if you take some good precautions (metal project box, heat sink, fuses, etc) you should be good.

If you want to be really careful, get an irreversible blow thermal fuse and attach it to the circuit.
 

andersonEE

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Thanks for the advice.

Now I'm a little worried this light won't be bright enough. The R2 isn't in the binning guide, but the Q5 gets ~110 lumens @350mA so the R2 (WG) is probably about the same. 6 x ~100 lumens is only 600 lumens. I was hoping to replace a 60 watt incandescent which would be about 900 lumens.

Any other driver suggestions?
 

purduephotog

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Thanks for the advice.

Now I'm a little worried this light won't be bright enough. The R2 isn't in the binning guide, but the Q5 gets ~110 lumens @350mA so the R2 (WG) is probably about the same. 6 x ~100 lumens is only 600 lumens. I was hoping to replace a 60 watt incandescent which would be about 900 lumens.

Any other driver suggestions?

You can get an xitanium driver that will do 700ma. There are also a couple of 'new' DX drivers besides the one you mentioned that do higher currents.

Meanwell makes a whole slew of drivers, some going up to insane levels.

You could also skip the cree dies and go with bridgelux- someone else was looking at one... pick up the 30 watt DX 320ma driver and put 5 or 6 bridgelux 400 lumen units in series.
 

AnAppleSnail

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Thanks for the advice.

Now I'm a little worried this light won't be bright enough. The R2 isn't in the binning guide, but the Q5 gets ~110 lumens @350mA so the R2 (WG) is probably about the same. 6 x ~100 lumens is only 600 lumens. I was hoping to replace a 60 watt incandescent which would be about 900 lumens.
Each bin gives about 7% more lumens. They seem to match across LED packages - you'll get about 107 lm at 350 mA (At 25*C junction temperature).

The incandescent puts light in all directions, so it loses plenty. Look hard at good diffuser choices.
 

hank

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> metal enclosure

Put yourself in the shoes of your fire insurance carrier or fire department inspector.

Your 110v wiring comes through a standard electrical box anyhow, the kind that are* set into the ceiling.

You can 'gang' those boxes like a stack of pancakes; you might be able to put your driver into one of those. If not, definitely use a proper metal box, big enough to dissipate heat.
____________
* (or should be -- I've found houses where someone just poked a hole in the sheetrock, pulled a piece of Romex through it, and wired a light fixture to that; found it when the twisted wire connections shorted out because someone rotated the light too far.)
 

blasterman

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I will definitely feel safer with this combo. Also, I think the 3000K CCT will be alot nicer.

Yep and yep. That's a new Bridgelux, and they put out impressive amounts of light for the money. The color temp also tends to blend better inside a house, unless you actually want to stick out.

Just remember that Bridgelux LEDs have hefty heat sink requirements, and if you're used to wrking with 3watt LEDs get ready to 'go to school' :whistle:. It will also be a very bright point light source without diffusion.

The power supply will work fine. It's pricey, but it looks well made. There are cheaper 1amp Mean Well drivers, but by the time you add in shipping from another site it's often not worth the trouble. Newark needs a much wider variety of drivers.
 

LEDninja

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If you are worried about safety:

Non UL power supplies should not be used.

UR rated power supplies have to be de-rated to 1/2 power if used in an air tight enclosure.

Full UL listed power supplies can be used to rated power in air tight enclosures.
 

jason 77

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I second the idea of using bridgelux leds for home lighting. I used 3 BXRA-W0402-00000 LEDs for my bathroom vanity light and they put out more than enough light.

img0978f.jpg


While I made the driver myself, you could use one of meanwells etc. that the others have mentioned...
 

andersonEE

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Thanks for the help everyone.

Jason, your light fixture looks great. Kudos for doing the electronics yourself (I looked up your post). I think I will still get the Roal driver for better efficiency and dimming.

By the way, this light will be a ceiling-mount overhead light. My design idea was to take out the electrical box (which the incandescent light fixture is mounted to right now) and have the LED be facing downward almost flush with the ceiling. The heatsink would be above the LED in the attic (mounted between joists). Then I would have a round piece of frosted glass (12 inches diameter) "floating" about an inch or two below the LED. Since the led has a 120 degree light pattern, I think the glass would work well as a diffuser and it would give the whole fixture a really modern look.

My concern (I know...another one:laughing:) is that in the summer when my attic gets really hot, the heatsink will also get very hot. My current plan is to leave some space in the hole in the ceiling around the LED so that cool air from my house can rise up through and cool the heatsink. My air conditioning won't be as efficient... but my lighting will be. :twothumbs

Any comment or suggestions would be appreciated.
 

Illum

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  • Fuse the circuit
  • Shield the driver from weather, thats indoor and outdoor weather
  • Heatsink everything that has a potential to heat up if something shorted
  • Heatshrink all the wiring connections that a wire boss is too big for
  • Understand that heatsinks are heavy, do not go for less than optimal mounting methods.
  • if a fixture is too dim at 350ma, use a 700ma driver. If at 700ma its still too dim and ample heatsink exists then go for 1A driver. If at some point say a CREE XRE isn't giving the output that you need, but you don't have room for more LEDs, use an MCE in its place and drive that at 700ma. It'll get hot, but it'll beat the ariche anyday:grin2:
  • Do not try to tap too many drivers off the same branch, especially in bathrooms. Flipping on your hairdryer might be a cue to visit the breaker panel.

Now for a bit of sanity advice

  • If the fixture is heavy, post hardhat signs around and wear hardhats in the room [I'm wearing mine right now and I'm sitting in my living room]
  • If the fixture pulls itself out, do not use the same hole, if you have no other options, look for the most heavy duty expanding screw you can find.
  • Do not mount any aluminum on popcorn ceilings, especially if they have sharp edges, and especially if they are over 3 pounds and are 10ft above your hardwood floor.
  • Use wire bosses where possible, they will disconnect when fixture falls off
  • When fixed LED lighting fails, its usually the driver, but check the LED first before the driver, be sure to disconnect power first.
  • A cold joint that works is better than the 5th resoldering of the same joint
  • If you plan on scraping a fixture, kicking it, shooting it with your shotgun, or otherwise inflict severe damage to it out of frustration, grab a beer and take the day off.
 
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AnAppleSnail

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My current plan is to leave some space in the hole in the ceiling around the LED so that cool air from my house can rise up through and cool the heatsink.

Cool air doesn't rise, but your hot air in winter will. Blow a few bucks on a small computer fan and thermostat. Mount the computer fan in a way that it won't transmit its own vibration and run it at low voltage. Then you can just have house air cooling the heatsink without having your power bills go so high.
 

Illum

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if you have central cooling, mound your fixtures beside the vents...
If you do, and you set your A/C at 77F year round, prepare to use very hot emitters or install a condensation tray :ohgeez:
 

hank

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There are several reasons that taking out an electrical junction box and using a hole in the ceiling to cool your lights isn't a good idea. I'm not a contractor or inspector, just a homeowner who's challenged all sorts of details in the codes and surprisingly often found out that they were there for a reason based on experience.

You might find your fire insurance won't pay for a fire because the electrical junction box is required by code (because of long experience with how fires start, often at junctions). You might find your fire insurance won't pay because of opening a path for fire to get into the attic. You might find your roof warranty won't pay for premature failure of your roof because of opening a path for moisture from the living space (breathing, cooking, washing) to get up under the roof and condense causing dry rot, or freeze causing physical damage to the roof. Your air conditioning and heating, as you point out, rely on a closed space without an added 'chimney' that will pull in unconditioned air to replace what goes out.

Look up "derating" on the drivers you're considering (if they're UL- listed, don't just rely on the symbol, check the number, often UL certificates are fakes these days).

I just asked a driver maker about installing one of their drivers in an electrical box, for the same kind of application you're describing -- they gave me a pointer to the specific information I needed. Basically, I take the temperature inside the box after it's closed and then reduce the load on the driver til it doesn't overheat in the enclosed space.

You can stack boxes to make bigger space and more surface area.

You can buy sealed cans for downlights that close off the air path above the opening, so none of those 'hole in the roof' issues arise, while leaving enough room for cooling air to circulate from and to the room.
 
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