Ballast wiring question

May 24, 2003
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#1
Just got a replacement ballast for a T8 light that stopped working, it's actually odd, because when I touch the ballast hot to the power I get a small spark, so something is drawing power, but not enough to fire the bulbs. Unfortunately Home Depot does not carry the exact replacement but found one that is compatible or so I think. It's for T8-32w which is what I have. Only thing, this one only has 3 wires coming out, the red one is suppose to go to one end and connect to both bulbs, on both pins, then there are two separate blue wires that goes to the other end of the bulb, and one blue for each bulb, connecting both pins of the bulb. But I don't quite get how that works, how is the filament going to fire up if it's connected that way? The existing ballast has 7 wires. Each bulb gets 2 wires per end and there is just one that shares two pins of one end of the bulb. Makes more sense to me.
 

skull

Platinum Member
Jun 5, 2000
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#2
If I were you I'd take the ballast back, get some directs wire led tubes and hard wire her, fluorescents suck.
 
May 24, 2003
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#3
Oh forgot to update this, I decided to try it out anyway, figured what's the worst that can happen. Worked ok with that ballast. I think with the newer ones, the filament in the bulb is not used at all, the light is activated by simply applying a high voltage across both ends of the tube to strike it, and then it does current limiting to get it to 35w. At least that's my understanding of it. But either way it's clearly not using the filament if they work wired this way.

At some point I do want to look into hard wiring some LED bulbs but selection is still kinda poor for them, you pretty much get whatever color temperature is available, they don't carry all of them and they might change from one day to the next so you can never match them if you buy more later. I'm sure things will improve over time, then I'll switch at that point. I actually like the light fluorescents produce though especially for video/photography (I will probably vlog in the shop when it's done). LEDs always have that blueish tinge to them on camera.
 
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mindless1

Diamond Member
Aug 11, 2001
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#4
If I were you I'd take the ballast back, get some directs wire led tubes and hard wire her, fluorescents suck.
I prefer them in areas where the light stays on a fair # of hours, as long as it uses a modern (taken loosely, they've been around for over 30 years) electronic ballast so you don't have AC line frequency flickering. Typical T8 LED retrofits either produce significantly less light per bulb, or else the LED bulb seller is lying about true lumen output.

Typical cost effective LED retrofits have a much shorter lifespan than a modern T8 ran several hours per day. I am only referring to T8, not those pathetically short lived E27 spiral fluorescent bulbs, and only if kept on several hours at a time... but then if not on several hours at a time you might still get 15 years out of a $2 T8 fluorescent tube.

Don't believe it when an LED tube seller tries to claim they last 50K hours. That is ONLY what the LED in a perfect lab environment "might" achieve, before the bulb manufacturer throws out all best engineering practices to cut costs. The usual failure mode is not the LEDs themselves.

On the other hand in a very cold environment or frequent, short duration on/off cycling, LED wins hands down except for much less light per dollar and not much more efficient than modern T8 fluorescent (sometimes even worse) once you factor that you need more of them for the same amount of light.

Heh, they are what they are. My main gripe is misleading if not outright dishonest and fraudulent marketing. Once you weed through all that, they're worth considering for a new installation but if you already have a T8 fixture, it's a downgrade to me to switch to LED tubes.
 
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fritzfield

Senior member
Mar 4, 2003
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#5
I had 14 HD/Lowe's/generic T8/T12 fluorescent shop lights in my basement that never wavers from 68 degrees F and 2 in the garage that goes down to the 20sF in winter's coldest. The bulbs in the garage were always anaemic and flickered a lot and the ones in the basement died on average one or two per month, not to mention the lovely HUMMMM. Breaking the bulbs was always happening when I had to change the dead/dying. Long/short - I took em down 1 by 1 and removed the ballast completely and installed Single Ended LED replacement tubes I found on Amazon.

No more flickering or breakage or HUMMMM. I think the light is better/crisper as well. Not sorry to see the fluorescent go away.

BTW - not 1 of the new LED replacements has failed at 2 yrs service - 32 bulbs - woulda already bought another box of fluorescent replacements and then some.
 

mindless1

Diamond Member
Aug 11, 2001
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#6

fritzfield

Senior member
Mar 4, 2003
387
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#7
Obviously, Cheapo Depot shoplights must always come with bad ballasts. All of em. Whodda thunk. Glad I changed em out and I'm not breaking any bulbs.
 

mindless1

Diamond Member
Aug 11, 2001
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#8
^ Yes either generic junk or just died from old age. Every ballast dies of old age eventually as do LED lights or anything really, with that age tending to be on the shorter side for cheaper products.

When I replaced my old ballasts they were over 20 years old. Can you assume your 2 year old LED lights will last 18 more years? I wouldn't unless it's a premium product. Just like with fluorescent ballasts, the LED driver board will probably be the failure point, sooner than that, despite manufacturers giving crazy long lifespan estimates based only on the LED itself in an ideal lab environment. Granted, some major brands are now making more conservative lifespan estimates than the loft 50K hours fiction that was popular.

Maybe you can repair the LED lights later, spending only a buck or two. Maybe not. At least they're (usually) not potted like fluorescent ballasts so you have access to the circuit, but on the other hand T8 ballasts are somewhat universal while LED drivers aren't, usually proprietary so if you can't repair one that fails, the whole strip may need replaced, and since you need more LED strips for the same amount of light, thus more driver boards, the failure rate may increase.

It's not rocket surgery, the world has been successfully using tube fluorescent lights for decades. If anything they are a mature technology while low cost LED strip lights are still in their infancy in this cost-cutting era where things that should last a long time, don't necessarily.
 
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May 24, 2003
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#9
I think one issue with LED is that because it's "new and better" the companies skimp a lot on the driver circuits or even the LED modules themselves knowing people will probably buy them anyway as the fact that it's LED is almost a selling point on it's own. When LED Christmas lights first came out they were horrible. They used low quality LED modules, and they flashed like crazy because they don't bother to rectify or smooth the AC. I noticed that over the years they have gotten better though. Commercial LED lighting is getting to be pretty good but consumer is probably still a bit iffy. I like the idea of the T8 LED bulbs that you can retrofit, but selection is still kinda poor. I like to be able to choose the color temperature, but you pretty much get whatever the hardware store carries as they won't carry different ones. I think this will change over time. Not too much a fan of the fixtures that have fixed LEDs, as color temperature is an issue, you might like the look of a certain fixture but it won't be the color temperature you want. You can't just change the bulbs.

Going to stick to fluorescent for now but by the time I start hitting a point where I get more ballast failures and have lot of burnt bulbs, the LED retrofit ones might be better then I can just rewire the fixtures.
 

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