Electric-Light
Senior Member
The UL has three designations for tube LEDs.
A = Drop in replacement. Some limitations. May not work well with older single voltage ballasts (120 only, 277 only etc), but most likely to work with 120-277v rated instant start. The lamp contains rectifier diodes and a few other passive components, but fixture ballast does the grunt of the ballasting. All ballasts have a limited life (50,000 hrs rated for good quaity ones), so if they're already near that, you won't get miracle out of them.
B = This is the one commonly known as "ballast bypass", the worst of all even though it seems to be the favorite of many energy service sellers to create justification for the complex installation. Line voltage is brought directly to tombstones. The pin assignment of four pins is all over the map and each manufacturer does whatever they want. The consequence is the possibility of bolt on short circuit with full available fault current if a fluorescent lamp or a LED lamp with a different configuration is installed. The entire transistorized LED ballast is tucked away into the lamp just like CFLs/LED bulbs and its voltage or flicker regulation performance can suck terribly. Relocating the LED ballast into the tube doesn't make the loss disappear despite "eliminate ballast loss" is frequently touted by those who push this retrofit.
C=Matched proprietary lamp/AC adapter system. Ballast function can be entirely in the AC adapter or shared between the lamp module and the adapter. There is a lumens per watt difference between 1990s T8 ballast and modern NEMA Premium ballast. But the difference between a new NEMA Prem T8 ballast + type A tubes, vs type C proprietary system is unclear. Provides the best dimming performance. But remember that time when you needed a replacement power cord/Ac adapter for some stuff that is obscure and factory only?
http://www.gelighting.com/LightingWeb/na/solutions/led-tubes/index.jsp
http://www.gelighting.com/LightingW...Tubes-At-A-Glance-Sell-Sheet_tcm201-69379.pdf
http://www.gelighting.com/LightingW...g-Refit-Solutions-Whitepaper_tcm201-69385.pdf
GE's explanation of "ballast bypass" vs "drop-in" LED lamps. The merit of disposable integrated ballast is lost for 4-pin tube LEDs due to lack of uniformity in pin assignment.
Where do you go to learn about the merits/lack of merits about LED retrofits? Where do the people who teach you the stuff get their facts from? My guess is the manufacturers. Not that you can't piece together imaginary conditions to make what GE is saying correct using real parts, but don't assume the "before" figures are representative or the new solution is fair. The rebuttal to GE's claim was made using GE's own premium T8 sell sheet.
The LED sales department must of had a brain fart and forgot about the offerings of their own LFL selections. Day 1 rating of 2200 lm/18W (122.2 LPW decaying to 85.5 LPW @50,000 hrs) is not much of an improvement over something lasting about the same and giving day 1 of 2175 lm/21.5W (101 LPW decaying to 93 LPW over the same period).
A = Drop in replacement. Some limitations. May not work well with older single voltage ballasts (120 only, 277 only etc), but most likely to work with 120-277v rated instant start. The lamp contains rectifier diodes and a few other passive components, but fixture ballast does the grunt of the ballasting. All ballasts have a limited life (50,000 hrs rated for good quaity ones), so if they're already near that, you won't get miracle out of them.
B = This is the one commonly known as "ballast bypass", the worst of all even though it seems to be the favorite of many energy service sellers to create justification for the complex installation. Line voltage is brought directly to tombstones. The pin assignment of four pins is all over the map and each manufacturer does whatever they want. The consequence is the possibility of bolt on short circuit with full available fault current if a fluorescent lamp or a LED lamp with a different configuration is installed. The entire transistorized LED ballast is tucked away into the lamp just like CFLs/LED bulbs and its voltage or flicker regulation performance can suck terribly. Relocating the LED ballast into the tube doesn't make the loss disappear despite "eliminate ballast loss" is frequently touted by those who push this retrofit.
C=Matched proprietary lamp/AC adapter system. Ballast function can be entirely in the AC adapter or shared between the lamp module and the adapter. There is a lumens per watt difference between 1990s T8 ballast and modern NEMA Premium ballast. But the difference between a new NEMA Prem T8 ballast + type A tubes, vs type C proprietary system is unclear. Provides the best dimming performance. But remember that time when you needed a replacement power cord/Ac adapter for some stuff that is obscure and factory only?
http://www.gelighting.com/LightingWeb/na/solutions/led-tubes/index.jsp
http://www.gelighting.com/LightingW...Tubes-At-A-Glance-Sell-Sheet_tcm201-69379.pdf
http://www.gelighting.com/LightingW...g-Refit-Solutions-Whitepaper_tcm201-69385.pdf
GE's explanation of "ballast bypass" vs "drop-in" LED lamps. The merit of disposable integrated ballast is lost for 4-pin tube LEDs due to lack of uniformity in pin assignment.
Where do you go to learn about the merits/lack of merits about LED retrofits? Where do the people who teach you the stuff get their facts from? My guess is the manufacturers. Not that you can't piece together imaginary conditions to make what GE is saying correct using real parts, but don't assume the "before" figures are representative or the new solution is fair. The rebuttal to GE's claim was made using GE's own premium T8 sell sheet.
The LED sales department must of had a brain fart and forgot about the offerings of their own LFL selections. Day 1 rating of 2200 lm/18W (122.2 LPW decaying to 85.5 LPW @50,000 hrs) is not much of an improvement over something lasting about the same and giving day 1 of 2175 lm/21.5W (101 LPW decaying to 93 LPW over the same period).
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