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Thread: LED lamps in new fluorescent fixtures

  1. #11
    Join Date
    Jun 2010
    Quote Originally Posted by Little Bill View Post
    You just replace the lamp like you would on any fixture. The driver for the LED is in the tube. Not sure about Lowes but I can get the tubes the same place as the fixture, from my supply house.
    Does it have a brand name? I don't know how they know how to wire it. There's no standard for integral-ballast double-capped bi-pin linear lamps or retrofit lamps. Every designer or assembler have their own philosophy for the way their product is wired. Some are wired to two pins to make it only necessary to touch only one socket per lamp to retrofit. Some are wired end-to-end, and some do funky diagonal or weird funky jumper to detect insertion.

    Things can be UL listed to be used for designing into a factory made product but not be appropriate as a general purpose product. Think of unpolarized appliance cord. There are permissible applications but it's up to the appliance manufacturer to ensure the proper application. Some LED fixtures are made with an off-the-shelf light engine. The fixture manufacture mounts this on a fixture and threads the wire out the through the stem and complete it with a bezel. It's on the fixture manufacturer to ensure the complete fixture is UL listed.These inexpensive and poor light quality (no electrolytic capacitor means a ton of flicker) fixtures have exposed LED elements once the glass opel is removed and UL listing is dependent on not removing it.

    Direct wired double-ended bi-pin fixtures are dangerous.

    OSI SubstiTube meant for use with instant start ballast have the two pins on each end shunted. This is more accommodating for IMPROPERLY installed T8 fixtures with using a rapid start socket w/o a jumper, but when this lamp. When this lamp or normal fluoro lamp is dropped into a "direct wire" fixture, you have a short across the line which will knock out the whole circuit at best or have more serious consequences.

    There are shop-lites using this style of lamps, but the lamp module is soldered, shrouded, or otherwise anchored to make it clear it is not meant for user replacement.

    Quote Originally Posted by olc View Post
    Thanks for the info above.

    Update to my update: The Lithonia fixture I mentioned is produced over seas. It has a 5 year warranty but the parts are not available (I infer from the reps response) so the entire fixture would have to be replaced.

    Thinking out loud:
    For new installations I would think either:
    1. Remove ballast and install LED tube with integral driver.
    2. Remove ballast and install driver and LED tube.

    I would not think installing a fixture with (fluorescent) ballast and LED replacement tube on day 1 is a good idea.

    I'm trying to think what is best for long term maintenance.
    I know the local university uses fluorescent fixtures with LED tubes because of maintenance because the decision maker is the head maintenance supervisor.
    Why? The Philips dedicated InstantFit LED ballast and standard instant start ballast fits into the same mounting and wires up the same. The only difference is a tiny amount of efficiency and the ballast being dedicated for use with the InstantFit LED lamp module. The only thing it accomplishes is that if the lamp module fails, it wouldn't power a fluoro lamp. The most likely application failure of linear LED tubes come from using them in fixtures that require the upper portion to light up to work properly, like direct/indirect stemmed fixtures.

    I think the only purpose of existence of that proprietary LED ballast is so the same existing lamp products can be used to compete in "type C" category, which is for LEDs that requires purpose-specific LED ballast, while "type A" is to work with existing fluoro ballast. OSI's type C system require differnt SKUs of ballast + lamp module. You can assume that components are not interchangeable between different brands for "type C". You can't run other brand's LED module in InstantFit LED ballast. Make sense?

    Instantfit LED tube = use with either electronic T8 fluoro ballast or InstantFit brand electronic LED ballast which makes no practical performance difference.

    InstantFit LED ballast + other LED module = NO

    OSI Type C lamp is for use with OSI Type C ballast. Since the lamp is purpose made, its a DC output ballast and I believe all the circuits are in the remote ballast.

    The biggest limitations are optical and LED element cooling. The white finish on a T8 lamp is a phosphor. It's an essential component of functionality. The white finish on LED tubes is just a diffuser, which steals some lumens. So when you put it inside a fixture, you end up with two layers of diffusers.

    The reason to use 48" T8 lamps designed for T8 electronic ballast is immunity from market volatility. You should pair the two so they're mutually approved for warranty purposes initially but the approval isn't needed for functionality which means standard T8 ballast, or LED lamp for T8 ballast can be used to repair the system down the road at the expense of not having the cutting edge lm/W or wide range continuous dimming.

    Also, fluorescent drop-in T8 lamps are often unsuitable for high ballast factor systems, such as T8 high-bay. The durability is rated on common, 0.87 BF ballasts. They may allow the use, but durability of LED increase in their suck factor more severely than T8 lamps. The standard lm/W specs and life rating is not valid on 1.2BF system. They may have a separate rating available upon request, or they might not have enough data and can only tell you an estimate that it will suck worse than usual and the warranty is reduced.
    Last edited by Electric-Light; 07-28-17 at 06:41 PM.

  2. #12
    Join Date
    Dec 2010
    Tennessee NEC:2008
    Quote Originally Posted by Electric-Light View Post
    Does it have a brand name? I don't know how they know how to wire it.
    I believe they are "Tamlights".
    As far as knowing how to wire them, there is nothing to it. Hot/line goes to one side of the socket/tombstone and the neutral goes to the other pin. The two pins at the other end are just to hold the lamps in the fixture.

    So if it's a 2-lamp fixture, two sockets on each end. One end has the hot/neutral to each socket the other end has no wiring.
    If you aim at nothing, you will hit it every time!

  3. #13
    Join Date
    Jun 2010
    Quote Originally Posted by Little Bill View Post
    I believe they are "Tamlights".
    As far as knowing how to wire them, there is nothing to it. Hot/line goes to one side of the socket/tombstone and the neutral goes to the other pin. The two pins at the other end are just to hold the lamps in the fixture.

    So if it's a 2-lamp fixture, two sockets on each end. One end has the hot/neutral to each socket the other end has no wiring.
    Their spec sheet is Extremely Sketch. This is a classic example of sales based company fixture assembly company and these companies are supporters of ballast bypass because it wouldn't give a reason for their product to exist without them. Fixture assemblers may pass customer to the LED engine supplier for warranty issues and LED engine supplier will leave it up to the fixture assembler and the LED ballast fry-out can be due to improper fixture design.

    "The LEDT Series offered by Tamlite Fluorescent(Electric-Light comment: WTF?) are designed and UL listed to work with LED tubes."

    "The LEDT Series offered by Tamlite Lay-ins is a series of commercial grade recessed lighting fixtures designed and UL listed to work with LED tubes."

    Starting Method
    Input Voltage
    120-277 VAC
    Operating Temp
    -20°C ~ 45°C (-4°F ~ 113°F)
    Lamp Wattage
    18W (Per Lamp)
    122 lm/W (Per Lamp)[/qute]
    Power Factor
    Lamp Style
    Linear T8
    Socket Type
    G13 Bi-pin
    Lamp Operating Current
    65-155mA (Per Lamp)
    Driver Type
    Rated Life
    50,000 Hrs."

    Those specs are for those of LED ballast and LED element combination. The life rating depends on the actual operating temperature of those two parts inside the temperature which is affected by fixture design and installation location.

    Lamp Lumens
    2200 lm (Per Lamp)
    Number of LEDs
    80 (Per Lamp)

    ^Down to the every nut and bolt including number of individual LED elements for a shell with sockets. WTH??

    Perhaps the product is UL listed but the conditions and intended purpose of product for the submission is different from how the products are marketed.

    Accepted practice for L. E. D. type luminaires is to specify using the fixture net output, which parallels "wheel horsepower".

    Fluorescent fixture is the chassis and lower drive train and the specs include "percent efficiency" and light distribution pattern.

    The ballast and lamp combo is the upper drive train which determines the wattage taken from the utility and the "net crankshaft horsepower".

  4. #14
    Join Date
    Jun 2010
    So, here's the thing.

    The only difference is fixture optics. Lite Puff makes the highest uniformity for direct lighting, but its inefficient however you put it.

    25W premium T8 and premium TLED are pretty much the same performance for indoor use, except double life fluorescent lamps are more durable and longer lasting. Can't use 25W T8 fluoro outdoors.

    I have no idea how the light distro works out actual data to show optical advantage... and there is no data that I know of. You should get samples of pair or two each of T8 25W lamps and 2200 or 2400 lumen TLED and compare the uniformity and distribution in actual fixtures. If you specify double life T8 25W FLUORO lamps, the lamp life and lumen maintenance is superior to TLED.

    You can get cheap, "value TLEDs" that is inferior in output and durability at prices that rivals double life RE 80 premium T8 25W lamps, but you're not going to get premium TLED for the same price in pallets quantity.

    Sylvania Ledvance systems

    QHE2X32T8/UNV ISN (<-normal high efficiency T8 ballast)

    LED15T8/L48 Qty x 2 general purpose LED lamp for T8 ballasts
    (there are more than one wattage and lumen types by the way)

    36 watts / 4,400 lm brand new (3,520 lm @ 80% level) (using 25W FLUORO, it's 38W /3,600 lm with L ballast, 43W /4100 lm with N ballast)
    The brand new state lumen: 122 lm/W.
    The LEDs can expect to degrade to 70% output in 50,000 hrs, so I would use 80% or 3,520 lm between the pair as the design lumen. (as opposed to 3630 over 38W with L, or 4100 with 43W with N...

    You can buy those two together and get a 6 year system warranty.
    Stick spare lamps elsewhere, or stick T8 fluoro lamps and you can generally expect them to work together fine.

    Here is their proprietary external ballast-lamp combo kit. You can not use the lamp in anything else or put any other brand lamp into that ballast . LED19T8/L48/F/1x2HE/841/UNV (a kit)
    38w 4,700 lm (3,800 @ 80%)
    124 lm/W <less than 2% gain.
    They say LEDs degrade to 70% in 60,000 hrs.

    Comparing just the lamp lumens, what you end up with is an essentially a zero net gain compared to 48" 25W T8

    The only major difference: fluorescent lamp has all the output evenly split over the entire cylindrical shape. The LED only emits on the bottom half, but not in a perfect semi circle, so it would be center heavy and there's really no data on percent efficiency efficiency difference of the fixture or adverse impact on uniformity. (bright work surface, dim walls)

    In conclusion, lamp+ ballast performance of TLED/proprietary driver combo = TLED + T8 ballast =25W fluoro + 25W T8.. in descending order by acquisition cost. Expect around 100 mean lumens per watt. Nobody cares about what the lumens per watt is when the system is brand spanking new.

  5. #15
    Join Date
    Dec 2011
    Ocala, Florida, USA
    Like Electriclight, I would shy away from a new installation of a fluorescent fixture with LED retrofit unless the retrofit kit includes the entire light distribution portion of the fixture. He buried it in his post, but basically how the light distributes from the lamp is different between an LED and fluorescent tube. The entire assembly including reflection diffusion creates the light pattern of a fixture. Going to LED WILL change this.

    I know what I don't know, and I know where to go to find it!

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