Fluorescent light question

[fecmech]

Gentlemen: I have a 2 bulb 40wt florescent fixture with a marginal ballast. When I turn it on (new bulbs) the bulbs don't quite light until I lightly touch both bulbs with my 2 fingers. What is actually happening by the touching of my 2 fingers that causes the lights to instantly light?? I know I need a ballast but what does the touching of the fingers actually do?

[Finster101]

It would probably be cheaper to just replace the entire fixture with an LED one. Better light too.

[fecmech]

It would probably be cheaper to just replace the entire fixture with an LED one. Better light too.
That's my plan when the finger thing quits working

[.45Cole]

have you looked into rope leds, after doing that here and there that's what I would do now. Half the cost of individual fixtures, run them on the perimeter of the garage ceiling and down the center for no shadows.

[Winger Ed.]

what does the touching of the fingers actually do?

Good question.

I think it works along the lines of when our parents used to beat us kids.
We'd straighten right out and get with the program.

[sparky45]

Can't an existing Fluorescent fixture be retrofitted with LED?

[Finster101]

Good question.

I think it works along the lines of when our parents used to beat us kids.
We'd straighten right out and get with the program.


I think more like putting a piece of bacon on the rabbit ears so you could get that one channel.

[Finster101]

Can't an existing Fluorescent fixture be retrofitted with LED?

Yes but for $30.00 or less you can replace the entire fixture and have all new.

[DickelDawg]

Could be a loose connection at the tombstone prongs (fixture connector at the end of the tube) or the prongs at the end of the lamp are not inserted properly (make sure the indicator((the bump on the metal end of the lamp)) is facing directly down.

[Frosty Boolit]

Maybe static electricity discharge giving a little bit more juice to get the voltage up to the necessary voltage to fluoresce

[Winger Ed.]

Can't an existing Fluorescent fixture be retrofitted with LED?

Unless the fixture is something really fancy, it's not cost effective.

You'd have to change the ballast and the (smaller) 'tombstones' the bulb ends fit into.
Even then, the fixture's slots the tombstones fit in may be a different size too.

[Ithaca Gunner]

They make direct replacement LED bulbs for existing fixtures, BUT unless you by-pass the ballast and rewire the fixture, they don't last very long at all. You may have something loose or broken in your fixture, just replace it with an LED and be done with it.

[Shawlerbrook]

Ditto on just getting a new LED fixture.

[405grain]

I replaced the old florescent lights out in the garage/shop/man cave with LED fixtures years ago. It's much brighter, uses less electricity, bulbs seem to last forever, and they don't contain any mercury vapor like florescent lighting. There's no ballast to wear out, they never flicker like a worn out neon sign, and are just in every way better. I agree with everyone here that says just make a direct replacement with LED lighting.

[Hossfly]

Loose connection, clean with sand paper till shining.

[fecmech]

Guys: while I appreciate your suggestions on a fix, that's not my question. My question is: Why does a very light touch on the glass surface of the florescent tube cause the light to lite?? What is going on there to make the tube lite from the touch? I want to know why that happens, not how to fix the light.

[Winger Ed.]

They work sort of like a stick/arc welder to start & light up.
The arc (and light bulb) takes more power to start than to keep the light or welding bead going.

As the bulbs and/or ballasts age, it takes a little more and a little more burst of power to strike the arc and light it.
In the old days, floresent lights had a separate starter you could change.
In modern times, the starting extra burst of electricity capability in inside the ballast.

Our body works like a capacitor and stores a little bit of static electricity.
Touching the bulb grounds it, and it gets a little 'omph' to help it start up.
As it continues to age/wear out, it takes more and more power to strike the arc until
even touching it isn't enough, and the bulb is just dead.

[Scrounge]

Can't an existing Fluorescent fixture be retrofitted with LED?

They can, but it's usually more expensive to do it that way. For some reason, the fixtures are generally cheaper than the replacement lamps. Also, with the old ballasts still in there, you're using more power than you would with pure LED lamps, so you lose some of the benefit of switching to LED's.

Another also, but only important to those who have friends or family with Lupus or other autoimmune disorders, fluorescents put out a lot of UV, where LED's don't. UV aggravates the Lupus/immune disorders to some extent.

Bill

[bakerjw]

You draw the plasma charge from one end to the other.
A year ago, I pulled all of my ballasts and put in replaceable LED bulbs. NEVER looked back.

[fecmech]

Thank you Winger ed and bakerjw I thought it might have something to do with a the body's static charge.

[DocSavage]

I have a shop light in my cellar I just replace bulbs with compatible LEDs. All the other fixtures had the ballast removed installed new LEDs.

[Mal Paso]

When you touch the tube your capacitance to ground stimulates the arc inside the tube that generates the uv that stimulates the florescent material on the inside of the tube to produce visible light.

I vote for costco shop lights for $20 or less.

Sometimes capacitance to ground will cause a LED shoplight over a cement floor to glow a little when shut off. Sometimes reversing the plug will fix it.

[Finster101]

When you touch the tube your capacitance to ground stimulates the arc inside the tube that generates the uv that stimulates the florescent material on the inside of the tube to produce visible light.

I vote for costco shop lights for $20 or less.

Sometimes capacitance to ground will cause a LED shoplight over a cement floor to glow a little when shut off. Sometimes reversing the plug will fix it.

That is interesting. I have a couple that do it. No way to reverse the plug though, they are three pin.

[farmbif]

usually if you open it up, the light fixture, you will probably encounter plastic covered wire nuts connecting the fixtures wires to the plug wire. if you reverse them just leave the ground wire alone. I dont know about anyone else but ive got boxes of fluorescent tubes and a bunch of fixtures., they still work, dont see much reason to buy something new to replace something that still does what its supposed to do. I dont understand the logic of new sometimes, to do what send more of my money over to china to get the latest greatest stuff. if I were to get new led stuff what would I do with the florescent fixtures I got now, send them to the dump?
maybe I could apply the logic to guns
the 30-06 is no good anymore, cuz its old and the shell uses a lot of powder, a lot more the new 6.5 creed moor that all the gun magazines have super stories about, yeah I better take that old 30-06 and put it in the trash can cuz I got me a new fangled latest greatest super wiz bang 6.5. the bullets use less lead and the shells takes less powder.

[GhostHawk]

"5000 Lumen 4 ft. LED Hanging Shop Light"
https://www.harborfreight.com/5000-lumen-4-ft-led-hanging-shop-light-64410.html

It is a single strip LED light that puts out a LOT of light.
Just need a plugin handy or an extention cord. Comes wired with a pull chain switch in the light.

I used a pair of these for a Hydroponics project, worked great.
Now I have them all over the house.

[JRLesan]

Interesting; I have a two bulb 'rapid start' fixture (96" single pin tubes) that does the same thing. However, I don't have to touch the bulb(s) with my finger. Just get very close (1/8" or so) and they both light up. Always kinda wondered what was going on but ruled out loose connection somewhere when I noticed I didn't have to touch the bulb...

[smoked turkey]

I'm in the middle of a lighting upgrade project here. Basically i'm keeping my 48" tube four bulb drop in troffer fixtures. They are heavy duty commercial grade that are far and away better than the the cheap junk being sold now. So it is my opinion that going with a rewired ballast free fixture with LEDs is the best way for me to go and is a definite upgrade from the old 40 watt florescents I had. The replacement tubes can be had for about $5 each. The T8 tubes will work on the T12 sockets, so no problem there. I'm converting a 4 tube florescent to a 4 tube LED for $20. My labor for the project is free to me. So the bottom line is that if your fixtures are some of the old good ones, keep them in place and convert them to no ballest LEDs.

[JSnover]

Now that the question has been answered I don't feel so bad about hijacking the thread... so here's my question: I replaced ballasts in my garage a while ago. They were probably late 70s vintage and all were marked for industrial use only - not for residential installation. I would have expected the opposite; that residential ballasts couldn't used in industrial locations. Any idea what the difference was?

[Dieselhorses]

Evidently LED bulbs work even if you don't remove ballasts lol

[Ithaca Gunner]

Evidently LED bulbs work even if you don't remove ballasts lol

They will, they won't last as long.

[one-eyed fat man]

Some LED fixtures do not comply with FCC Part 15 requirements. "Cheap" LED lights often have spurious emissions that can cause trouble with radio communications (https://www.dco.uscg.mil/Portals/9/DCO%20Documents/5p/CG-5PC/INV/Alerts/1318.pdf?ver=2018-08-16-091109-630).

[GregLaROCHE]

For me the big difference is that LEDs consume a lot less electricity. They are are supposed to last longer, but I’ve had a couple that didn’t last long at all.

[smoked turkey]

Speaking about post #28 concerning the replacement of ballast with commercial ones. In my experience a ballast is a ballast. The commercial variety concerns mounting the ballast in the fixture. Mine slide into pre-made tabs on one end and are held in the fixture with nuts on the opposite end. So I think it is simply a mechanical difference in the mounting. The older magnetic ballast are bad about leaking the black compound which leaks out with heat over time. The newer solid state ballast are lighter and will usually slip right in where the older magnetic type was. Sometimes the solid state ones are shorter than the older magnetic type and may need to be fitted into the old position. If the newer solid state ballasts are compatible with LEDs it will state such on the wiring diagram of the ballast. However I think a program of eliminating the ballast and replacement with no ballast LEDs is the way to go if the fixtures in question are of good quality.

[gwpercle]

I think more like putting a piece of bacon on the rabbit ears so you could get that one channel.

More like getting the youngest child to stand next to the TV and touch the rabbit ear ...
No way in heck my Mom Or Dad would stand for wasting good bacon when you had perfectly good kids around that worked just as good as TV reception inhancers ... Bacon was not wasted in our house ... as long as my little brother would hold the antenna we could watch Three stations ... although one station was "snowy" ... we could hear it good !
Gary

[Keyman]

I replaced all my florescent fixtures with LED fixtures as it costs .90 cents per kWh in bush Alaska. They also will start at 50 below zero, and very bright.:happy dance:

[Duckiller]

Moved about a year ago. New house had a large shop with floresent lights. About half of them worked. Previous owner said some of them never worked. #2 son who works for the company that provides power said switch to LED. Cheaper and better light. I did. Told contractor that if all lights didn't work I wasn't going to pay him. He laughed. All lights now work and I have great light. Not sure about cost because #2 son pays electric bill.

[Finster101]

I replaced all my florescent fixtures with LED fixtures as it costs .90 cents per kWh in bush Alaska. They also will start at 50 below zero, and very bright.:happy dance:

I don't ever plan to try and confirm that first hand.

[Keyman]

What part, the 50 below, or the 90 cents? :happy dance:

[Finster101]

I'm in Florida! Do you really need to ask? :drinks:

[15meter]

That is interesting. I have a couple that do it. No way to reverse the plug though, they are three pin.

Maybe need to check the polarity on the outlets that have lights that glow? My house was wired by a guy that put what ever wire came to hand first to what ever screw was easiest to get to first.

I replaced virtually every plug in my house almost immediately after moving in. Prior owner's painting technique was roll right over outlet, cover and all. That's how I found out about his wiring ability.
It was pretty ugly.

But not quite as bad as his carpentry work. I replaced the patio door several years after moving in. The seals on the thermopane glass had gone away. He had used 8" landscape spikes to mount the door.

Most of his carpentry used was what ever nails he happened to steal from FoMoCo that week. Just curious where they used the landscape spikes at in a Ford stamping plant.

[varmintpopper]

Fecmech
Go here : https://ec.europa.eu/health/scientific_committees/opinions_layman/en/energy-saving-lamps/l-3/3-cfl-characteristics.htm#:~:text=A%20fluorescent%20lamp %20generates%20light,254%20nm%20and%20185%20nm).

Good Shooting

Lindy

[samari46]

I had some 4 lamp flourescent fixtures in the garage. Put them in when we moved into the house in 1996. In the winter had to wait until they finally made up their minds to light up. Off to Harbor Freight and bought 6 of the 4000 leumen LED fixtures. So now have plenty of bright white light and with the pull chains only turn on or off as needed. and if they go belly up, replacements are cheap. Frank

[JSnover]

Speaking about post #28 concerning the replacement of ballast with commercial ones. In my experience a ballast is a ballast. The commercial variety concerns mounting the ballast in the fixture. Mine slide into pre-made tabs on one end and are held in the fixture with nuts on the opposite end. So I think it is simply a mechanical difference in the mounting. The older magnetic ballast are bad about leaking the black compound which leaks out with heat over time. The newer solid state ballast are lighter and will usually slip right in where the older magnetic type was. Sometimes the solid state ones are shorter than the older magnetic type and may need to be fitted into the old position. If the newer solid state ballasts are compatible with LEDs it will state such on the wiring diagram of the ballast. However I think a program of eliminating the ballast and replacement with no ballast LEDs is the way to go if the fixtures in question are of good quality.
Thanks.
These were the magnetic ones and had a good amount of 'tar' on them. The solid state ones went right in. I'm not up to reworking the garage but when I lit the shed last month it was LEDs. The difference was amazing!

[bangerjim]

Scrap it! Don't waste time and money on a new ballast if you can even find one these daze!

I am in the process of replacing all 14 of my 40 watt old flor shop lights (working and non-working) with LED's. They only cost about $30 each (complete!) at Lowe's. Don't go for those "replacement LED tubes for old lights!). Buy the entire fixture and enjoy the BRIGHT (4K lumens) they provide for pennies a day.

banger

[John Wayne]

To answer the original question, by touching the bulbs you became the best path to ground. Check your ground with a 3 prong plug in type tester available at any home supply, cheap. If it lights correctly at the outlet with good ground, then the fixture, inside the fixture, the ground wire was not screwed into the metal frame of the fixture. You would not want to be standing on a wet floor and touch the housing of that fixture. I watched EMT's try to start a neighbors heart who placed his hand on the vent-a hood above the stove, wet floor and couldn't let go till my other neighbor cut the power at the panel. All that power going through Mr. Byers and it did not trip the breaker. He died a week later.

[frkelly74]

We are in the process of replacing all the old fluorescent tubes at Church with LED tubes. I am scrapping the ballasts and it seems that the market is flooded with old ballasts. They are the same price as sheet Iron right now. It is exceedingly simple to re-wire an old fixture to accept LED tubes. The last ones I bought were less than $10 each. The power company gave the church about 300 , 4000K LED tubes , I have about 200 installed. They are nice.

[JSnover]

Scrap it! Don't waste time and money on a new ballast if you can even find one these daze!

I am in the process of replacing all 14 of my 40 watt old flor shop lights (working and non-working) with LED's. They only cost about $30 each (complete!) at Lowe's. Don't go for those "replacement LED tubes for old lights!). Buy the entire fixture and enjoy the BRIGHT (4K lumens) they provide for pennies a day.

banger

You can still find them at Lowe's but I'm a convert: Next time they start acting up they're gone.

[sharps4590]

Until LED fixtures became affordable, the last 2-3 years I worked probably 1/2 of my work as a contractor was updating existing fluro fixtures to LED. It most assuredly was cost effective. IF, as has been mentioned, you have quality fixtures I would still recommend updating them to non ballasted, LED, T-8 lamps. Why would anyone leave a maintenance item in a fixture when you don't have to?

Winger and Mal Paso have the right of it regarding why your lamps come on when you touch them.

[Soundguy]

Good question.

I think it works along the lines of when our parents used to beat us kids.
We'd straighten right out and get with the program.

It's a charge issue with the ionized gas and your static charge. Think of it as a truck jumping another truck with a weak battery. Your static charge upped the potential in the ionized gas of the light to allow for it to go on... and excite the phosphor.

For all us/you electrical guys out there.. yes that is a oversimplification.... but it's close.

[gwpercle]

Why did three channels come in when my little brother held one of the TV rabbit ears ... he didn't have to hold both ... just one !
Watching three different channels on that black and white screen was something ...
...we usually got one channel with a sometimes picture and sound and one snowy channel with sound and all the rest of the channels was nothing but static ! The good old days .

[bangerjim]

Why did three channels come in when my little brother held one of the TV rabbit ears ... he didn't have to hold both ... just one !
Watching three different channels on that black and white screen was something ...
...we usually got one channel with a sometimes picture and sound and one snowy channel with sound and all the rest of the channels was nothing but static ! The good old days .

The human body, with all it's surface area, usually makes an excellent RF antenna.

And no, those were NOT good old days!

[fecmech]

Just want to add a little factoid to the original post. I never got around to replacing the fixture because as we went into the fall the light started working by itself. It has worked all through the winter till a couple weeks ago as we got into our summer pattern and the humidity level in the basement rose a bit. I now again must touch the bub to make it light. The humidity evidently affects something.

[Shawlerbrook]

HF and most other discount places have LED fixtures for less than $20. Only way to go.

[45_Colt]

Just want to add a little factoid to the original post. I never got around to replacing the fixture because as we went into the fall the light started working by itself. It has worked all through the winter till a couple weeks ago as we got into our summer pattern and the humidity level in the basement rose a bit. I now again must touch the bub to make it light. The humidity evidently affects something.

Yep, it is the humidity that affects them and causes the no-light-up. Had/have the same issue here, both 2' and 4' bulbs do it. It seems that this all started once the government mandated higher efficiency bulbs. Never had a problem prior to then (back in the Bush Jr days).

Swapping to an electronic ballast works, but is expensive and is now difficult to find them.

The shop fixtures ended up having the ballasts removed and direct wired to the bulb connectors (tombstones). Then T8 LED bypass bulbs installed (into a T12 fixture, they go right in).

Other then the rewire and install of the LED bulbs nothing else was done or replaced. Now I enter the shop, flip the switch, and have light. Sure as heck beats going around fondling the fluorescent bulbs to get them to light up.

Oh yea, the two 4' fixtures in the laundry room also got the LED treatment. With one fixture having a bad ballast it was a win/win there.

45_Colt

[WRideout]

When you touch the tube your capacitance to ground stimulates the arc inside the tube that generates the uv that stimulates the florescent material on the inside of the tube to produce visible light.

I vote for costco shop lights for $20 or less.

Sometimes capacitance to ground will cause a LED shoplight over a cement floor to glow a little when shut off. Sometimes reversing the plug will fix it.

Same reason that on the old portable radios, one could touch, or even get near the telescoping antenna, and it would receive better.
Wayne