Rather than replace a dead ballast in a fluorescent fixture, I've decided to simply bypass and move to LEDs. However, I think I may have grabbed the wrong kind of replacement tubes the other day in Home Depot. They are in the Philips "InstantFit" range, and are specifically intended to be used without having to remove the ballast. But my question is the following. Is it merely that you don't have to remove the ballast (i.e. but you can if you want)? Ot is it the case that you must not remove the ballast?†

I ask because all the instructions I've been able to find are a tiny bit ambiguous (to me). In the "Warnings and Safety" section on page two of the data sheet it says††:

Philips LED T8 InstantFit lamps will only operate properly on compatible instant-start ballasts.

However, there are two ways to read that. One, which I now think is the intent, is:

Philips LED T8 InstantFit lamps will operate properly only if used with a ballast, and it must be of a compatible, instant-start type.

But the other is:

Philips LED T8 InstantFit lamps will operate properly with or without a ballast. However, if a ballast is used, then it must be of a compatible, instant-start type.

Anyone know definitively which it is?

Various numbers (from the box):

  • Model: 9290012265
  • Ordering Code: 20T12 EM LEF/48-4000 IF G 10/1


† If so, that's fine. But then I need to replace them and get the kind intended for ballast bypass, of which there are several.

†† That link is to the "global" version. Curiously, the almost-but-not-quite-identical US version does not make the same explicit point.

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    It’s the wrong kind, return and get the right thing. The funny thing is we used an amprobe and noted converting using the ballasted LED lamps doesn’t actually save nearly as much energy. Presumedly the longevity factor is still a plus but to maximize energy savings as well the ballasts need to go.
    – Tyson
    Jan 27, 2018 at 18:13
  • Yeah, I read that elsewhere. I was actually just about to install a new ballast (also from Home Depot), and only went down the LED route because yet another Home Depot dude mentioned it. At this stage, what should ave been a job of an hour at most has lasted three days and counting! At least I'm learning stuff :-) Especially the point that LEDs for the ballast bypass situation achieve that by having their own ballast -- what you called "ballasted" I assume? That's presumably not a big choke, like the original ballasts were, right?
    – tkp
    Jan 27, 2018 at 19:50
  • @Tyson have you tried upgrading your ballast to a modern type? It sounds like either the old ballast, or the ballast-LED dynamic, is what is wasting your energy. Jan 27, 2018 at 19:51
  • @tkp I hope you're learning not to do business at Home Depot. Seriously, a proper electrical supply house would've made sure you walked out with the right stuff in the first place. Their prices are cheaper on most random stuff (often shockingly so). On commodity endcap items, they lose, but but their quality is good because their customers are electricians. A cheap item doesn't mean $1 saved, it means a $200 go-back. Also, HD/bigbox clerks have a lot of mis-information, such as what you just said. Jan 27, 2018 at 19:55
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    @poorplanning Look for others. One electrical supply near me does the same, but 1/2 mile down from them, is an excellent one. Who knew? I don't dispute that it's possible for an expert to find quality stuff there, but OP's torture of being misled in circles with wrong products and bad advice is just such a typical story around here, and my experience too. Jan 27, 2018 at 20:53

6 Answers 6


Interesting thing about being human is the brain is wired to see what it expects to see. It's hard to turn that off, even if you're a ship spotter or pilot.

There is such a thing as LED bars which work both ways, either with a ballast or direct-wire. But they're a lot bolder about claiming so!

The ruling word is "only" and your first interpretation is correct.

The data sheets you link are highly ambiguous. But that's not so weird when you look at the Electrical Code, NEC 110.3b:

NEC 110.3(b) Equipment must be installed and used in accordance with any instructions included in the listing or labeling requirements.

The operative words are instructions and labeling. A data sheet is neither.

So you need to review the labeling on the item, or the instructions in the box.

Be warned: if you find that data sheet inside the box, that is bad. It means this thing is probably counterfeit: the counterfeiters found the same PDF you did because it was the first/easiest document to find.

I am always suspicious of the bargain priced items at the big-box. Even legit brands often "make" items specifically for one big-box store. If you have a part number that only associates with one big-box, run screaming.

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    one could argue any such conversion is violating the instructions of the fixture manufacturer.
    – agentp
    Jan 27, 2018 at 19:45
  • @agentp that's up to UL. UL is at liberty to require a retrofit manufacturer to say "Do not put in fixtures whose instructions do not authorize LED retrofit". They are also at liberty to not. Jan 27, 2018 at 19:49
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    Well I guess the horse's mouth, as it were, is the label they have on the bulb itself. It says, "USE ONLY WITH COMPATIBLE FLUORESCENT BALLASTS..." So it's no less (nor more) ambiguous than the data sheet. I'm a stickler for grammar, and the (mild) dissonance concerns whether they are warning about using the wrong ballast -- i.e. the emphasis is on that "compatible" -- or about using the wrong or no ballast. I'm going to switch them, but if I was the relevant design manager in Philips, I'd want the wording changed to make the intent completely clear.
    – tkp
    Jan 27, 2018 at 19:56

I can confirm Phillips InstantFit work with ONLY specific ballasts and do not work without ballasts. I tried with Utilitech lights and with ballast removed to no avail. I'm done with fluorescent anyhow. They don't work very well in my garage for Michigan winters and don't last very long. I'll get LEDs that don't need ballasts.

  • Modern fluorescent is quite excellent, particularly programmed-start ballasts. They preheat the tube "as long as it takes" with 2-3 second startup times on very cold days, and once they strike, they burn properly, temperature be damned. Modern tubes are also excellent with the best color rendering available in any efficient lamp. I have actually been doubling down on fluorescent, and pleased with the results. Also don't have to deal with any low-grade cheapie LED "tubes" from China. Speaking of junk, Utilitech is one brand to avoid, along with Lights of America and Feit Electric. Oct 28, 2018 at 7:22
  • Yep Utilitech are junk. I think the ballasts are garbage, but fixtures are ok and easy to rewire, so maybe can salvage with led's with drivers. From what I've read it seems preferred to run led's that work without ballasts if possible.
    – Bret
    Oct 28, 2018 at 20:53
  • Yes, I agree, if running LEDs it's best to rewire and run without ballasts, unless you arer quite sure you plan to rollback to real fluorescent at some point in the future, or your facilities staff is exceptionally dull and may intermix. Putting a real fluorescent in an LED-converted fixture will be very bangy, or do nothing at all, depending on whether they are single-end or double-end wiring respectively Oct 28, 2018 at 21:15

The Installation Guide contains important information and notes regarding the installation and operation of the InstantFit T8 lamps. Please note the important points below:

  • Philips InstantFit T8 LED lamps are suitable to replace T12 fluorescent lamps
  • Philips InstantFit T8 LED lamps require non-shunted G13 (medium bi-pin) lamp holders (tombstones)
  • Philips InstantFit T8 LED lamps are intended for use in conjunction with a magnetic ballast. Please do not connect the lamp directly to mains voltage 120/220/240/277 VAC.
  • Ensure all parts and accessories are in the package, including instruction guide, label, driver and InstantFit T8 lamp
  • Modifications to the product void the warranty
  • Compatible with T12 rapid start magnetic ballasts
  • Please refer to www.philips.com/instantfit for the latest ballast compatibility guide
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    Hello, and welcome to Home Improvement. Thanks for the answer; keep 'em coming. And, you should probably take our tour so you'll know how best to contribute here. Oct 5, 2019 at 2:21

If the led tube comes with a 'starter' replace the original neon's starter with the one that comes with the led tube and you'll be fine, if no starter is supplied you will almost surely have to rewire the fixture excluding the ballast.

  • LED linear tubes that are direct wire come with a driver inside the lamp, drivers are different than ballast. Yes there are retrofits that are both ballast and direct wire compatable.
    – Ed Beal
    Oct 28, 2018 at 10:09
  • This comment may only apply to European fixtures/retrofit bulbs... I've installed some Philips retrofit bulbs in Germany and this was the case, but my US fixtures don't have this extra component--the "starter" seems to be part of the ballast.
    – S'pht'Kr
    Dec 30, 2020 at 19:53

I purchased a Philips instafit LED tube and it didn't work with my old ballast, so rather returning it, I took the whole thing apart.

The LED light was double ended, with a 160C Thermal cutoff at both ends, followed by a solid state noise suppression capacitor, followed by a 160 volt microfarad electrolyte capacitor and then the light strip.

The electrolyte capacitor is the killer for AC functionality. The electrolyte capacitor defeats the use on AC, as the capacitor plates will charge and then discharge 60 times a second due to the alternating current. Thus no juice gets to the light strip.

So it is not a safety issue, but just bad design from Philips that prevent the use of these instafit bulbs without a ballast.


LED stands for light emitting diode, so not an AC device. The light is emitted when forward biased, so a rectifier is needed to avoid high current in the case of reverse bias and then current limiting to provide the correct operating current. Does not need a ballast but might work with one.

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