I'm looking at retrofitting fluorescent fixtures in my basement for single-ended LED tubes. The electrical and wiring concepts I have down; I could probably do it with my eyes closed (but anyone working on line voltage circuits with their eyes closed is an imbecile that deserves what's coming).

What I don't get is that all the instructions have you cut all the wires right at the ballast (makes sense, so you have longer wires to work with)... but then many of them go on to explicitly state to leave the now-useless ballast in place! It'd make sense if they had you cut maybe 4-6 inches from the ballast, so it could be wired back in in the future if desired, but with nothing but wire stubs it seems to me the ballast is a useless brick in the fixture. Is there some code/safety/etc reason I'm not seeing that mandates keeping a paperweight in your fixture? Or is it okay to just uninstall it entirely and send off to e-waste?

For reference, I'm in the US (in case it's an NEC/NFPA/whatever code requirement). If it's due to a code requirement, insight into the logic behind said code would be appreciated too. I know most codes, even the arcane, archaic, and convoluted ones, have (or at one time had) a basis in personal or fire safety, so I'm curious.!

EDIT: I've added a picture of my fixture... It looks like there was an old ballast in there, possibly magnetic, and they did the same thing: cut it out electrically but leave it mounted. I'd be quite happy to remove both.

enter image description here

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    To hazard a guess, I'd say it's to reduce the number of people who simply throw them in the trash. Leaving it in is even lazier and doesn't require them to successfully persuade you of the importance of environmentally responsible disposal. Jan 25, 2017 at 20:40
  • I was thinking it might be something along those lines... hoping someone has some more definitive insight into the matter :)
    – Doktor J
    Jan 25, 2017 at 20:55
  • It might be that sometimes the ballast holds the fixture together or up, and removing it could in some situations cause trouble. Jan 25, 2017 at 21:32
  • @ShimonRura, many people simply can't be persuaded--they have to be forced. See our current consumption of fossil fuel as evidence. It's not a matter of laziness.
    – isherwood
    Jan 25, 2017 at 21:53

1 Answer 1


First, that fixture looks permanently hardwired. If so, you'll want to add a ballast disconnect. Code requires it, unless you argue that the fixture is now ballastless. But it's so darn convenient that I add them immediately upon starting work, and then, turn the power back on!

Cutting the wires off at the ballast is someting I only do to ballasts which are dead. It's already been wirenutted from the previous ballast swap, I would just do it at the wire nuts.

Generally, ballast instructions are generic and simplified, try to come up with a universal instruction and you can see where it's hard. Potential reasons for the "leave the ballast" instruction include:

  • different ballasts require disposal in different ways, and it's complicated and they don't want to open that can of worms
  • in particular, they don't want to scare the hell out of people with talk of PCBs
  • it may greatly reduce the weight of the fixture, with unknown consequences
  • it will shift the fixture's balance point, relevant to chain-hung fixtures
  • removing the ballast may leave holes on the fixture uncovered, which Code would disallow
  • in some bad installations, the screws holding the ballast also help hold the fixture to the ceiling.
  • Well yes, I intend for the fixture to be "ballastless"; I assume that's the intent of the stickers that come with the LED tubes saying the fixture has been modified and can no longer operate fluorescent lamps. I can take care of disposal so #1 and #2 are addressed. The fixture seems pretty sturdily attached to the floor joists so I think #3 #4 and #6 aren't an issue.
    – Doktor J
    Jan 26, 2017 at 2:32
  • I know that. I'm saying when the inspector asks "where's your disconnect", the answer "there's no ballast" might work. Or might not. Being in a residence is also a defense. Jan 26, 2017 at 2:55
  • The disconnect requirement only seems to apply to electrical discharge lamps; a complete removal of the ballast (and application of appropriate markings to indicate so) combined with the fact that it is now single-ended wiring should (theoretically) exempt the fixture from this requirement shouldn't it?
    – Doktor J
    Jan 26, 2017 at 18:19
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    Feel free to litigate with your inspector whether LED conversions are still discharge light fixtures. I win every fight I take on, and I wouldn't touch that fight with a 10 foot pole because it's too much a gray area. Anyway, who cares? They cost $1 and I find disconnects so useful that I use them even when I don't need to, because you can easily de-energize a single fixture without plunging the room into black. No reason for a knockout behind a ballast, no idea what the hole might be. They won't sweat a screw hole. Jan 26, 2017 at 20:07
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    Oh, your pictured installation is typical. Having done many ballast swaps, often with good used ballasts, I prefer hoardish gobs of extra length. Why? Because I've searched at length, and have not found a source for sanely priced fluorescent fixture wire. You can't just use any random grade of solid-core 18AWG wire, it needs to have particular insulation qualities. What I've found is usuriously overpriced. Let me buy the stuff for 10 bucks a 250ft roll, and all my installations would be neat as a button, because I would have confidence that I could always get more wire. Jan 26, 2017 at 20:51

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