In my basement, I have three fluorescent light fixtures, two of which don’t work correctly. The ends of the bulbs light up dimly in exactly the same way they would if the bulbs were burned out but replacing the bulbs doesn’t help. I’ve been told that the “ballast” (whatever that is) is burned out and needs to be replaced. Given that these are very basic, utilitarian light fixtures hanging from a dropped ceiling and using standard four foot fluorescent bulbs, I’m told that I’m better off replacing the entire fixture.
I know nothing about electricty or home wiring. Is any of this true?
Ballast is a step up transformer. Takes 120v and makes it several kv. I don’t recall the exact mount.
They aren’t hard to replace. You have to match the specs. Lamp type, number lamps, Watts etc.
I’ve bought mine from Grainger.
here’s a few examples
The older lights had a starter. Its inexpensive and easy to replace. There’s some on that Grainger page I linked.
In other words, yeah, just replace the whole thing.
The reason most people replace the whole fixture is that the ballast is a large percentage of the fixture cost. When I managed a property, the replacement ballast was $80 for each 4-tube fixture, and each had dozens of wires connected to it. If we’d had to pay an electrician to make the replacement, it would have been cheaper to replace the whole fixture (which, if memory serves was about $120). But they were just paying me free rent, so we replaced the ballast.
One other advantage to replacing the whole thing: the sockets that fluorescent bulbs fit into can crack or lose tension over time. If you replace the ballast only to have to replace an old socket the next month, you’ll be kicking yourself.
the ballast is a current limiter.
old magnetic ballasts do wear out.
there are now more efficient fixtures. you can get one with T8 bulbs and electronic ballast which use less electricity and don’t make noise (hum).
you can find replacement ballasts though a new fixture may be similar in price.
dispose of old bulbs and ballasts at a waste collection specific for them. governments or businesses may have drop off locations.
I’d start by looking at the old bulb (lamp). T-12, 4 foot was the most common for decades.
Bulb Watts? 40 Watt was very common.
How many in the fixture? 2 or 4?
look through Grainger and find a ballast that matches. Then check the dimensions of the case and make sure it will fit in your fixture.
You’ll save some money over the cost of a new fixture. But, not a whole lot.
Many thanks for all the kind info. aceplace57, I’ll check out Grainger after I get off work. I think it’s also wise for me to start pricing new fixtures as well though.
I have replaced one of these; I went to Home Depot to get the replacement, but you have to match the specs. Replacing the ballast really isn’t any more difficult than replacing the whole fixture, but if you know nothing about wiring this may not be the place to start.
The decision is based on how much you’re willing to spend an electrician vs. how much time effort are you willing to spend learning some basics about wiring. This job is not particularly hard but a mistake can be costly.
Commercial fixtures for offices and apartments are designed for servicing. I repaired several for my employer.
The newer cheaper residential fixtures are probably throw away items.
I replaced an old 2-tube fixture in my kitchen with a new electronic one. The new electronic ballast equipped unit eliminated the very annoying buzz of the old one and it also lights up nearly instantaneously when the switch is flipped on. The old one would start very dimly and slowly build in brightness over a few minutes.
A replacement ballast for the old one was within 10$ of the cost of the entire new fixture (40$ vs 50$). Because the new fixture was E-Star energy efficient, I received a rebate of 25$ from my electric utility tipping the cost question far in favour of the new fixture.
Replacing a ballast is almost always cheaper and less time consuming for someone familiar with wiring.
If the fixture has other issues, old, dated looking etc replacing the whole fixture isn’t much more work and adds very little to the cost.
As an electrical apprentice I had the pleasure of doing a ton of commercial work. Jobs such as upgrade every fixture in this 500,000sqft office building from T12’s to T 8’s. Projects like that made for many full days doing nothing but changing bulbs and ballasts.
To identify if you are capable of changing a ballast or not go to HD select the correct ballast look at the wiring diagram on it.
If finding the right ballast and understanding the diagram are within your capacity changing it should be a breeze.
If not changing the fixture is an easier project.
Just in case it’s an older style that was not a selfstarter do you see one of these fluorescent starters? This used to be what failed almost all the time and they are cheap.
On some fluorescent fixtures, the capacitor portion of the ballast (at least that’s what I’m assuming it is, since it’s not a full transformer) is a small dull-gray cylinder about the size of a B-celll battery adjacent to one set of “bulb holder” terminals. It goes into place and comes out with a twist. As I recall, these are not terribly expensive, and will fix the stated problem the majority of the time.
(On preview, I see Harmonic Discord has pictured one of them (which we always called “the ballast”) as a “fluorescent starter”/)
Just a note since no one else has pointed it out ‘Ballast’ was a manufacturer of transformers, their name just stuck. Kinda like people calling circular saws ‘skil saws’
For a while other manufacturers tried very hard to convince people to not call them ballasts. In recent years they’ve admitted defeat and I’m guessing the trademark?'s expired as pretty much every manufacturer labels their product ballast now.
The last time I changed a ballast, new sockets were included and already attached. If anything, it’s more a test of mechanical dexterity than electrical ability to get the sockets slipped into the right set of slots and tabs at the end of the fixture and to dress the wires (they’re usually all a yard long) so they don’t get pinched when you re-assemble the fixture.
Now, if you’re dealing with a $15 “shop light” dangling off chains in the garage or basement, you’re better off just replacing the whole fixture. Might as well upgrade to T8s.