Paul, an LED tube just has the LEDS on the "down" side, so not sure why you are talking about reflector loss. Also not sure why you are bringing corncob bulbs into it. I thought we were talking about LED tubes.Overall it’s a waste of money. A dedicated LED fixture, lumen for lumen, is cheaper.
A fluorescent bulb emits a radial light pattern and the fixture needs a reflector and a diffuser lense to be efficient. The reflector is not very efficient and the lenses throw off goofy patterns with “corn cob” LEDs. And you have to go in and disable the ballast so you are already rewiring and hacking it. It is far cheaper to just replace the whole thing in the long run.
The confusion is usually the LED fixtures have two “downsides”. The first is they have little ur no light “spillage”. You get light where you want it, no more or less. So don’t expect to light up “fringes”. That’s a good/bad thing. Second is the physical size and light patterns are adjustable by the manufacturer. A square 2x2 fixture can generate a rectangular light pattern like the old tube because it uses lenses instead of a reflector. So relighting with LEDs might require a little rethinking.
I converted a 4 ' 2 tube luminare in my basrment. They supplied 4 new lamp holders rated for 600 volts. I marked where I installed the black energised 120 volt wire. When i do some more going to install a fuse holder with a halve amp not time delay fuse. Would not use them on circuits feed from a 277 volt 20 amp circuit unless each unit had its iwn fuse. I would only go with the type that does not use the exidting ballast.With the retrofit T8 bulbs put in old fixtures and making the sockets line voltage (120/277) usually on a 20 amp breaker and often times replaced by a untrained maintenance person and over 40 years as a licensed Electrician have seen fluorescent sockets destroyed by people installing lamps what is the main opinion about the liability of putting in these retrofits with line voltage on sockets with no amp/ voltage rating I can find.
The primary concern with type B LED retrofit is the availability of line feeding directly into the tombstone with many thousands of amps of available fault current and there's no absolute standardization of wiring scheme, so some use double ended feed, some have shunted ends, some feed on one end of bi-pin double end lamp. Violent short circuit situation isn't restricted to inserting a fluorescent lamp. A TLED of different model that is configured different is just as liable to cause it. It's not as much of a concern with single pin double capped lamps, because the only way to feed them is from both ends and a direct short isn't possible.I have installed many, and seen no issues. 8' T-12s have had line voltage directly to the disconnect ends for decades, and fluorescent-ballast open-circuit voltages have been as much as the high hundreds for as long.
Blue sky is 10k.Also if you go for 3500k instead of fluorescent 4500k the light is closer to optimal for human eyes (natural sunlight, 3500k) which makes everything more visible even if the foot candles say otherwise. This is light efficacy, good for another 20-25% although as I said the FC meter doesn’t measure lighting efficacy.
if you bypass it, that simply moves the ballast into the tube and that comes with the disadvantage of longer dark ends, thus reduced light emitting surface and premature failure of the integral ballast is an issue in totally enclosed and high ambient usage. Externally ballasted LEDs can usually get illuminated section length that is more or less comparable with actual fluorescent lamps.Blue sky is 10k.
On retrofits, avoid the LED lamps that use the existing ballast, best is to by pass the ballast.
See this paper from the lighting design lab
The LED tubes that run on existing fluorescent ballasts still have to convert the HV AC to LV DC.if you bypass it, that simply moves the ballast into the tube and that comes with the disadvantage of longer dark ends, thus reduced light emitting surface and premature failure of the integral ballast is an issue in totally enclosed and high ambient usage. Externally ballasted LEDs can usually get illuminated section length that is more or less comparable with actual fluorescent lamps.
Those circuitry are minimal and small. The line frequency ripple is already managed in the external ballast, so the line frequency ripple ride through is handled in the external ballast and that does not need to be placed in the lamp. This electrolytic capacitor is the part that has a finite life and proportional to temperature. When this is located away from the lamp, system life is improved. There are electrolytic capacitor free LED ballasts and you can recognize them right away by how much flicker gets passed into the light. Sweep your finger and you can see your finger draw a | | | | | | pattern in the air in a space lit under those.The LED tubes that run on existing fluorescent ballasts still have to convert the HV AC to LV DC.