Eiko t8 led typeB

Mparn

Member
We are in the process of replacing approximately 7000 lamps throughout our school district. The current lamps range from T8 to T12, all sorts of ballast magnetic, instastart, electronic. I am looking to go with an Eiko,17 Watt, ballast bypass, direct wire,dual ended lamp. Most of the district's lighting is 277 volt, and most of the rooms run off of two switches, with a shared neutral. I'm not really sure if we have a lot of voltage spikes, but I can say during a heavy lightning storm our power will dim briefly, without going out completely. Any ideas or suggestions to be aware of before starting this project? Such as surge protectors on panels, is eiko a good brand, is type B the way to go?
 

LarryFine

Master Electrician Electric Contractor Richmond VA
I believe the LED internal power supply does an adequate job of protecting itself, but I'm not brand savvy. What is Type B?
 

Dennis Alwon

Moderator
Staff member
We use those all the time for 120V. I believe the LED bulbs can take a wide variety of voltages so surges may not be an issue. We usually leave the ballast in and just disconnect it otherwise you have to put it in hazardous waste
 

JFletcher

Senior Member
You're going to want to play around with the Kelvin rating of the replacement bulbs, and get an ideal color before committing to buying 7000 of them. 3000 to 3500 k are yellow ish, 4000 or 4100k are brighter and more white. you may find the existing diffusers inadequate, or that 4-lamp fixtures only need two bulbs. There may also be a ton of busted or broken tombstones that need to be replaced. As far as the brand, I don't have any experience with them, but type B, the ballast bypass, are definitely the way to go.

As far as the dimming , it maybe the lightning is kicking out loads like air conditioning, and when they restart the inrush causes a voltage drop systemwide. you're going to be reducing the load on the system somewhere between 90 and 140 kilowatts by going to LED lights over fluorescent, that should help with brown out issues
 

Mparn

Member
You're going to want to play around with the Kelvin rating of the replacement bulbs, and get an ideal color before committing to buying 7000 of them. 3000 to 3500 k are yellow ish, 4000 or 4100k are brighter and more white. you may find the existing diffusers inadequate, or that 4-lamp fixtures only need two bulbs. There may also be a ton of busted or broken tombstones that need to be replaced. As far as the brand, I don't have any experience with them, but type B, the ballast bypass, are definitely the way to go.

As far as the dimming , it maybe the lightning is kicking out loads like air conditioning, and when they restart the inrush causes a voltage drop systemwide. you're going to be reducing the load on the system somewhere between 90 and 140 kilowatts by going to LED lights over fluorescent, that should help with brown out issues

Thanks, I did some lux testing on a few classrooms. I decided to go 2-bulb 4k lighting. This is going from a 3-bulb t8 and 4-bulb T-12. We have a wide variety of colors now. I would also guess that 20% of the districts current lamps are not working.
 

chris kennedy

Senior Member
Your existing T8's have shunted tombstones that may need to be replaced with non-shunted. Also the tombstones need to be listed for direct connection to a branch circuit.
 

Mparn

Member
Your existing T8's have shunted tombstones that may need to be replaced with non-shunted. Also the tombstones need to be listed for direct connection to a branch circuit.
The lights im using are a dual end. Hot goes to one end, neutral to the other. They also require each pin to be wired to. I am using shunted tombstones so each pin is energized.
 

Mparn

Member
I completed 5 rooms today. I get a random flicker on a lamp when I turn the other switch on in the same room. It doesn't happen all the time and when it does it's not the same lamp. There are 2 series of lights in the room, each on its own switch leg, with a shared neutral. Could this be because of the shared neutral? This didn't happen before. Did the ballast prevent this before?
 

Sierrasparky

Senior Member
I have a issue with the fact that the lamp sockets are now exposed to 277v. To untrained people this is could be a hazard.
 

Mparn

Member
I have a issue with the fact that the lamp sockets are now exposed to 277v. To untrained people this is could be a hazard.
Good point, I plan on having a meeting with maintenance and custodial staff about this. I have also placed new warning stickers inside each fixture
 

Russs57

Senior Member
I wouldn’t use the dual ended lamp. It isn’t the standard and may be discontinued or cost way more in the future.

I would buy a retrofit kit from respected name that would keep the fixtures UL rating. I’d assume they will come with new tombstones for live end of fixture. Be advised tubes are heavier so you want a good tombstone, not to mention one rated for line voltage. You want a solution with paperwork to cover everyone’s rear end. Small extra price to pay IMHO.

Personally I like the 5K color better. Seems a little much at first but is a much cleaner/ brighter look. Lot more POP than 4100 lamps. You want people to see your retrofit and notice a profound difference in lighting quality. On the other hand I hate the 6500 color.

PS, pay attention to angle of dispersion. Also going to have a little dark area near live end of tube that might be a deal breaker for some. Make sure building ownership signs off on sample room.
 

Mparn

Member
Thanks Russ.

All my sockets say they are rated for 600v. I can't seem to find anything saying UL doesn't approve of a consent 277 going to the socket. Can someone help me out on this? I would defiantly be replacing any worn or broken socket
 

Ragin Cajun

Senior Member
Just out of curiosity, what do the new LED lamps go for?

What's the warranty period? All the new fixtures come with a 5 year warranty.
Published lifetime at P-80?
CRI?

Thanks,

RC
 

Mparn

Member
Just out of curiosity, what do the new LED lamps go for?

What's the warranty period? All the new fixtures come with a 5 year warranty.
Published lifetime at P-80?
CRI?



Thanks,

RC
7500 lamps @ 6.48 is what I was quoted

2200 lumens
80 cri
50,000 hour burn
5 year material only warranty
What does p-80 mean?
 
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Ragin Cajun

Senior Member
7500 lamps @ 6.48 is what I was quoted

2200 lumens
80 cri
50,000 hour burn
5 year material only warranty
What does p-80 mean?

L80,not P-80,my typo. The fixture I spec for new work, at L80, lifetime is 60,000.

Surprised at only 2200 lumens. You will not get that out of the fixture. Did you take fc readings before and after?

What is the wattage, amps? Lumens per watt is important. So is the pf.
 

Mparn

Member
L80,not P-80,my typo. The fixture I spec for new work, at L80, lifetime is 60,000.

Surprised at only 2200 lumens. You will not get that out of the fixture. Did you take fc readings before and after?

What is the wattage, amps? Lumens per watt is important. So is the pf.
They are 17w, 129 lumens per watt. I did a lux reading on some desktops before, 3 bulb t8 I was getting 580-600, 4 bulb t12 rooms I was getting less the 400 (alot were burned out) . I replaced a whole classroom with 2 bulb leds and was getting 505-515 off the desktops, this classroom didnt have windows.
 

Russs57

Senior Member
The UL rated kits are really more about proper labels. If anything ever happens insurance companies will look for an out. Why put anyone in that position.

I know UL put out a warning about falsely labeled tubes that caused fires. Think James was manufacture. So there is bogus stuff out there. Another reason to get a rated kit from a name you know.

You will get best performance and life from external driver.
 

syhdeejey

Member
I have no idea of Eiko you said,butI think if the tubes pass the UL & DLC, then you don't have to worry too much. Anyway, UL&DLC are trustworthy authority.
Also, you don’t need to consider the lifespan of ballast if you choose Type B
 

Mparn

Member
Any idea why a random lamp or lamps would pulse when another series of lights are turned On? The lights in our building is on a multi branch circuit, I'm guessing it has something to do with the shared neutral.
 

ActionDave

Moderator
Staff member
Any idea why a random lamp or lamps would pulse when another series of lights are turned On? The lights in our building is on a multi branch circuit, I'm guessing it has something to do with the shared neutral.
Whatever the problem is it's not because the lights are on a multiwire branch circuit. Stop focusing on some superstitious fear that isn't based in reality.

The whole North American Continent is fed with power that shares a neutral. There may be some bad wiring causing problems, but electrons are too dumb to know what circuit conductor they are traveling around on, and LED lamps don't care what kind of circuit they wired to.

I think it's far more likely that cheap LED lamps are the problem.
 

Mparn

Member
Whatever the problem is it's not because the lights are on a multiwire branch circuit. Stop focusing on some superstitious fear that isn't based in reality.

The whole North American Continent is fed with power that shares a neutral. There may be some bad wiring causing problems, but electrons are too dumb to know what circuit conductor they are traveling around on, and LED lamps don't care what kind of circuit they wired to.

I think it's far more likely that cheap LED lamps are the problem.

Thanks for the reply Dave. I'm getting this random flicker on several rooms. I know it could be a possible wiring issue, but I can't believe that many are wired bad. I have personally wired a few offices by myself and feel they are all correct. I have also tried a Phillips 17w type B with the same flickering results.

Once all lights are on I have zero problems. The only time I have a problem is when a set is turned on, an existing set will have a random flicker on 1 or a few lamps. I can't say it's always the same lamp and sometimes it doesn't happen at all.
 

gar

Senior Member
180423-1029 EDT

Mparn:

You clearly have a single shot transient problem that only occurs at some turn on time. To light an LED for a moment it takes some amount of energy.

You have lights that are turned on and off by some sort of switch. What is the actual switching device between power (the hot wire) and the actual lights that flash when some other circuit is turned on? Is it an ordinary mechanical wall switch, mechanical contacts on a relay, or some sort of electronic switch?

How long are wire runs where hot and neutral wires are close together? A 4 ft long LED bulb will take a moderate amount of energy for a momentary flash. Could a 1000 pfd (0.001 ufd) capacitor provide enough energy?

An LED driver probably has a fairly large input capacitor with little current limiting in series. After being off this capacitor has near zero stored charge. If turn on to this capacitor occurs at an AC voltage peak, then you can expect a large input current spike at this turn on.

How could such a large current spike couple to what you think is an unconnected LED? Also there are likely large voltage spikes.

.
 

Mparn

Member
180423-1029 EDT

Mparn:

You clearly have a single shot transient problem that only occurs at some turn on time. To light an LED for a moment it takes some amount of energy.




You have lights that are turned on and off by some sort of switch. What is the actual switching device between power (the hot wire) and the actual lights that flash when some other circuit is turned on? Is it an ordinary mechanical wall switch, mechanical contacts on a relay, or some sort of electronic switch?

How long are wire runs where hot and neutral wires are close together? A 4 ft long LED bulb will take a moderate amount of energy for a momentary flash. Could a 1000 pfd (0.001 ufd) capacitor provide enough energy?

An LED driver probably has a fairly large input capacitor with little current limiting in series. After being off this capacitor has near zero stored charge. If turn on to this capacitor occurs at an AC voltage peak, then you can expect a large input current spike at this turn on.

How could such a large current spike couple to what you think is an unconnected LED? Also there are likely large voltage spikes.

.
The switch is an ordinary wall switch. Last week I turned all the lights on that run off the same panel and fired a few compressors from the RTUs. The lights didn't flicker or react in any way. I have plenty of slack between wires feeding the fixture and tombstones. Could that be a problem, too much wire?
If there are large spikes, how would I prevent this?
 

gar

Senior Member
180423-1230 EDT

Mparn:

(1) How many different LED fixtures in one room?
(2) How many different switched LED circuits in one room?
(3) How many switches in one box?
(4) How many different switching locations are in one room?
(5) How big is the room?
(6) Are all the lights in one room on the same phase?
(7) Are all the LEDs controlled by one switch close together in the room or scattered amongst LEDs on other switches?
(8) If you toggle on and off one circuit of LEDs what percentage of time does an LED flash in another circuit? Is it always in the same other circuit?

What does a tombstone have to do with the problem? I think that you can consider a single fixture when disconnected from its supply wires at the fixture to have almost zero likelihood of flashing from adjacent wires.

.
 

Mparn

Member
180423-1230 EDT

Mparn:

(1) How many different LED fixtures in one room?
(2) How many different switched LED circuits in one room?
(3) How many switches in one box?
(4) How many different switching locations are in one room?
(5) How big is the room?
(6) Are all the lights in one room on the same phase?
(7) Are all the LEDs controlled by one switch close together in the room or scattered amongst LEDs on other switches?
(8) If you toggle on and off one circuit of LEDs what percentage of time does an LED flash in another circuit? Is it always in the same other circuit?

What does a tombstone have to do with the problem? I think that you can consider a single fixture when disconnected from its supply wires at the fixture to have almost zero likelihood of flashing from adjacent wires.

.
12 fixtures per room, each fixture has 2 lamps.
2 circuits per room, most rooms are divided in half, some thirds
2 single pole switches per box.
Rooms are 30'x30'
They share the same circuit the ones I turn on and the ones that Flickr
They flicker immediately as the lights are powered.
I don't have any dimmers or 3ways.

Tombstones have nothing to do with it, I was just stating my 18 gauge in the fixtures may be fairly long with hot and neutral possibly close together.
 
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gar

Senior Member
180423-1301 EDT

Mparn:

To get electrical energy to a load you need some sort of closed electrical circuit (excluding radiated radio frequency energy, I think we are only concerned with conductive, capacitive, and inductive components describing your circuit).

Assuming your switches are really open when off, then to get energy to the flickered fixture means there has to be some form of capacitive or inductive coupling to the flickered circuit.

A very remote possibility is a very large transient voltage at the switch box that causes electrical breakdown of the open switch. I view this as a zero likelihood.

I don't believe there is inductive coupling.

Very likely you have capacitive coupling. You might have 20 pfd per foot between some wires. At most it is unlikely you have more than 60 ft of two hot wires from different circuits this closely coupled. Suppose you did, then the capacitance is 1200 pfd. Can I cause a flicker in a fixture with this amount of coupling? Depends. With sufficient voltage it might be possible.

I don't know your voltage. But get a 0.1 ufd capacitor or somewhat larger of sufficient voltage rating for your circuit voltage. Connect this capacitor between neutral and the hot wire to the fixtures that flicker on the output side of the switch that is off. The connection might be made at the switch box or anywhere near a fixture. See if this eliminates or in any way changes the flicker. This creates a capacitive voltage divider that should greatly reduce the source of voltage to a fixture, if capacitive coupling is the problem.

If capacitive coupling is yor problem, then you need to change the way wiring is run.

.
 

Mparn

Member
180423-1301 EDT

Mparn:

To get electrical energy to a load you need some sort of closed electrical circuit (excluding radiated radio frequency energy, I think we are only concerned with conductive, capacitive, and inductive components describing your circuit).

Assuming your switches are really open when off, then to get energy to the flickered fixture means there has to be some form of capacitive or inductive coupling to the flickered circuit.

A very remote possibility is a very large transient voltage at the switch box that causes electrical breakdown of the open switch. I view this as a zero likelihood.

I don't believe there is inductive coupling.

Very likely you have capacitive coupling. You might have 20 pfd per foot between some wires. At most it is unlikely you have more than 60 ft of two hot wires from different circuits this closely coupled. Suppose you did, then the capacitance is 1200 pfd. Can I cause a flicker in a fixture with this amount of coupling? Depends. With sufficient voltage it might be possible.

I don't know your voltage. But get a 0.1 ufd capacitor or somewhat larger of sufficient voltage rating for your circuit voltage. Connect this capacitor between neutral and the hot wire to the fixtures that flicker on the output side of the switch that is off. The connection might be made at the switch box or anywhere near a fixture. See if this eliminates or in any way changes the flicker. This creates a capacitive voltage divider that should greatly reduce the source of voltage to a fixture, if capacitive coupling is the problem.

If capacitive coupling is yor problem, then you need to change the way wiring is run.

.
Thanks, I there a reason why this problem didn't occur with the ballast and t12? Will this capacitive coupling cause any future problems, other then the random flicker when lights are turned on?
 

gar

Senior Member
180423-1627 EDT

Mparn:

The probable reason the T12s never flashed was need for greater energy, and possibly less coupling of transient energy.

.
 

Mparn

Member
180423-1627 EDT

Mparn:

The probable reason the T12s never flashed was need for greater energy, and possibly less coupling of transient energy.

.
Thank you for all your help today. Could this lead to bigger problems down the road?
 

Russs57

Senior Member
I suggest you look at IEEE 1789-2015 paper.

I suspect your problems have nothing to do with wiring, loads, or shared neutrals. Might prove interesting to see how many others notice this problem. Some are much more sensitive. I am....probably borderline epileptic!

This isn’t an unknown problem and why I advised trusted name. Also mentioned a driver would do better. Problem is most won’t work on 277.

Really hoping problem is some simple/stupid wiring issue. But do be aware some are suggesting there is a health risk. That is not a place you want to be with children involved.

Not trying to worry you. Just saying it might be time to slow down and evaluate things.
 

Mparn

Member
Gotcha thanks, I have tried 2 different brands (one being phillips) with the same results. This is a one time flicker on a lamp or few lamps when others are powered on. We've been monitoring the lamps daily for any flickering or strobing. No one seems to find evidence of either.
 
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gar

Senior Member
180423-1946 EDT

Russs57:

The
IEEE 1789-2015 has nothing to do with the problem that Mparn was questioning. Mparn described a single shot transient event. IEEE 1789-2015 is concerned with a continuous steady state modulation of light intensity. Should this be of concern? Yes. But it is not what the original post was about.

.
 

gar

Senior Member
180423-1958 EDT

Mparn:

If the single shot flicker does not bother anyone, then I would do nothing about it. I doubt that it is a resistive leakage problem.

The IEEE 1789-2015 brings up a much bigger and different concern. LEDs designed to provide some approximation of visible white or other color light generally are a blue or UV LED used to excite a phosphor(s) in the visible spectrum. These phosphors generally have moderate time constants of intensity decay. Thus, a square wave drive of the LED emitter that produces a square wave of blue or UV light may have a much more averaged visible light output. The time constants of the different colors from the LED phosphors may not and probably are not the same. Thus, the percentage of flicker from each color may differ.

For other reasons it would be good to drive LED chips from DC.

.

.
 
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Mparn

Member
I noticed a weak switch today in one of the classrooms. If i held the switch in the middle, the other series would get more of a random flicker. Could it be several of the switches are going bad? It even happened if I would just push in on the switch
 

gar

Senior Member
190426-2032 EDT

Mparn:

With inductance in a circuit and current flowing the opening of the circuit can easily produce thousands of volts to initiate a spark or arc across the opening element. This how an old automotive ignition coil works.

To test the sensitivity of electronic circuits to transient noise I have simply rapidly oscillated a plug to a two bulb 8 ft Slimline fixture.

Will arcing of a set of switch contacts in some fashion couple enough energy into a turned off LED circuit to momentarily flicker the LED? I don't know. But you may have demonstrated that it does.

.
 

Mparn

Member
190426-2032 EDT

Mparn:

With inductance in a circuit and current flowing the opening of the circuit can easily produce thousands of volts to initiate a spark or arc across the opening element. This how an old automotive ignition coil works.

To test the sensitivity of electronic circuits to transient noise I have simply rapidly oscillated a plug to a two bulb 8 ft Slimline fixture.

Will arcing of a set of switch contacts in some fashion couple enough energy into a turned off LED circuit to momentarily flicker the LED? I don't know. But you may have demonstrated that it does.

.
Thanks, the flicker happens in the circuit that is already on, when the other is turned on.
 

gar

Senior Member
180427-1005 EDT

Mparn:

At this point you need to define some words and run some independent experiments.

Flicker could means a number of different things. Is it a single shot event? Does it means 120 Hz ripple on light intensity? Not in your case, but it did in Russs57's comment. Does it mean an increase in intensity, or a decrease? Is it a short duration oscillation in intensity? Or etc.

Consider two 120 V switched 100 W bulbs fed from the same phase and sharing a common neutral of 10 ohms. A cold 100 W 120 V incandescent bulb is about 10 ohms, and hot about 144 ohms. With one bulb on its voltage is about 120*144/154 = 112 V. You would see a brightness difference in the bulb compared to a circuit with a much lower neutral resistance.

I have selected the bulb size and neutral resistance such that you can easily experiment. 100 W incandescent bulbs are still around, and a moderately stable resistance at 1 or 2 A and somewhat near 10 ohms is the resistance of a 1500 W space heater.

At the instant the second bulb turns on the voltage across the two bulbs is about 120*10/10 = 60 V. Actually a little less because you have 144 ohms shunting 10 ohms, or 9.35 ohms. So you will see a short time flicker in the dimming direction of the initially on bulb.

Now suppose the two bulbs are supplied from opposite phases. The 10 ohm neutral initially has a voltage drop of 120*10/154 = 7.8 V with one bulb on. At the instant that the second bulb is turned on two opposing currents exist in the neutral. Doing the math just after the second bulb is turned on I get a voltage drop across the 10 ohm resistor of about 54 V. This is in a direction to add voltage to the initially on bulb so that the already on bulb sees about 120 + 54 = 174 V. Thus, the already on bulb brightness momentarily increases a lot, bright flash.

When the turning on bulb reaches its high resistance the 10 ohm resistance has a voltage drop of about 0 volts, canceling currents thru the neutral, and the initially on bulb is slightly brighter than when it was the only load. You may not detect this.

The above is a suggested experiment that I have not played with but may illustrate how neutral impedance can affect components in a circuit.

LEDs have ballasts (power supplies) that may be pretty much like an uncharged capacitor at their input before turn on. Connecting an electronically ballasted LED at a voltage peak and large peak currents may flow.

.
 

Mparn

Member
180427-1005 EDT

Mparn:

At this point you need to define some words and run some independent experiments.

Flicker could means a number of different things. Is it a single shot event? Does it means 120 Hz ripple on light intensity? Not in your case, but it did in Russs57's comment. Does it mean an increase in intensity, or a decrease? Is it a short duration oscillation in intensity? Or etc.

Consider two 120 V switched 100 W bulbs fed from the same phase and sharing a common neutral of 10 ohms. A cold 100 W 120 V incandescent bulb is about 10 ohms, and hot about 144 ohms. With one bulb on its voltage is about 120*144/154 = 112 V. You would see a brightness difference in the bulb compared to a circuit with a much lower neutral resistance.

I have selected the bulb size and neutral resistance such that you can easily experiment. 100 W incandescent bulbs are still around, and a moderately stable resistance at 1 or 2 A and somewhat near 10 ohms is the resistance of a 1500 W space heater.

At the instant the second bulb turns on the voltage across the two bulbs is about 120*10/10 = 60 V. Actually a little less because you have 144 ohms shunting 10 ohms, or 9.35 ohms. So you will see a short time flicker in the dimming direction of the initially on bulb.

Now suppose the two bulbs are supplied from opposite phases. The 10 ohm neutral initially has a voltage drop of 120*10/154 = 7.8 V with one bulb on. At the instant that the second bulb is turned on two opposing currents exist in the neutral. Doing the math just after the second bulb is turned on I get a voltage drop across the 10 ohm resistor of about 54 V. This is in a direction to add voltage to the initially on bulb so that the already on bulb sees about 120 + 54 = 174 V. Thus, the already on bulb brightness momentarily increases a lot, bright flash.

When the turning on bulb reaches its high resistance the 10 ohm resistance has a voltage drop of about 0 volts, canceling currents thru the neutral, and the initially on bulb is slightly brighter than when it was the only load. You may not detect this.

The above is a suggested experiment that I have not played with but may illustrate how neutral impedance can affect components in a circuit.

LEDs have ballasts (power supplies) that may be pretty much like an uncharged capacitor at their input before turn on. Connecting an electronically ballasted LED at a voltage peak and large peak currents may flow.
Gar,

Thank you for all your help. Although you are way over my head, you have explained it to where I am able to understand. By "flicker" I mean, a single shot, one time, where the light dims or goes out. It happens really fast but you are still able to see it. You have to actually study it to see that it's dimming and not getting brighter.
 
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gar

Senior Member
180427-2131 EDT

Mparn:

My two bulb experiment is not as good as I would like. The high current pulse generated by randomly turning on an incandescent (I used 75 W for convenience) does not have an adequately high probability of having its maximum value and longest duration as compared with a controlled turn on at the voltage peak. I could barely detect the transient pulse compared to the steady state change.

For an illustration of incandescent turn on current see my photos P1 thru P4 at http://beta-a2.com/EE-photos.html .

In doing this experiment the bulb being turned on should be totally out of view. Do not look directly at the always on bulb. Shine it on a wall or use something to greatly attenuate the brightness.

Do not view what I am describing as over your head. Think about it and ask any questions. You seem to have a great interest for looking into why things you see occur.

.
 

gar

Senior Member
180428-1146 EDT

Mparn:

I would like you to run an experimebt if you can.

I took my only LED fixture, a 4 ft twin tube Costco shop light, and with a Powerstat (variac) adjusted the input voltage from 70 to 140 V with a GE light meter monitoring the light intrnsity and saw virtually no intenity variation.

Do you have any way to change the AC sine wave voltage to one of your fixtures? If so, then even a visual observation may tell us whether the light output is particularly sensitive to voltage.

In contrast I can take a Cree screw-in 9.5 W bulb and get good dimming control with a variable sine wave voltage source.

.
 

Kinexis

Member
i recommend trying the new led's in various parts of the building's for a period of time (honestly i would test for a year before replacing that many) before replacing everything with LED, there has recently been an article series in EC&M magazine about ground planes for LED drivers that talks about some of the issues coming up with LED's especially in older facilities. i would think you would have decent bonding throughout the buildings but i would test before committing to all LED. i have seen several facilities that have kept replacing LED's and i suspect it may be related to the issue discussed in the articles in EC&M, they were older facilities and not very well wired to begin with.
 

Kinexis

Member
i'm not finding anyone else addressing it in this forum, but there was discussion over concern of 277v at the tombstones, don't most fixtures like the op currently has have lamp start voltages of several hundred volts at the tombstones? when you install or remove a lamp on an energized fixture you are exposed to that voltage, your exposed when you remove because you can easily disconnect and accidentally reconnect. or is the secondary of most ballasts not grounded?
 

Mparn

Member
Our building were built in 1988 and 1999. Thanks for the info on the magazine, I'll look into that.

Kinexis, are you concerned with 277 at the sockets?
 

gar

Senior Member
180429-2206 EDT

LarryFine:

For a cold cathode tube, mono end electrodes, it takes a relatively high voltage, 600 to 1000 V, to initiate ionization of the gas. After initiation of ionization, then the arc voltage drop is relatively low. The power source to the tube must be of a current limiting nature. High leakage inductance in the transformer.

Once a tube has been initiated the mono electrodes become fairly hot from tube current and the initial breakdown voltage per half cycle becomes less.

In tubes with two pins per end and a small heater electrode at each end, the earliest fluorescents, a preheat circuit including what was called starter was used to lower the initial breakdown voltage.

.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
In tubes with two pins per end and a small heater electrode at each end, the earliest fluorescents, a preheat circuit including what was called starter was used to lower the initial breakdown voltage.
I have plenty of experience with starter-equipped fluorescent lights, and even have modified them with momentary switches to eliminate the starter. N.O. push-buttons to start the lights, and N.C. to extinguish them.

I've been doing electrical work for fifty or so years. I'll be 63 next month, and I did my first service upgrade when I was 15. I added a generator and T/S years later, and critiqued my own work. Proud to say I did everything correctly. :p
 

Kinexis

Member
Our building were built in 1988 and 1999. Thanks for the info on the magazine, I'll look into that.

Kinexis, are you concerned with 277 at the sockets?

no, i would put warning stickers on them though. say something like "DANGER 277Volts at tombstones, site policy is to de-energize light before servicing", or "De-energize or light will be damaged when servicing".

and also make sure everything is rated for it, the wire may be good at the high voltage only for start-up and not for continuous operation at the voltage i don't know though, just throwing it out there because i would look into it if i was going to do that

i always thought you should de-energize a light when changing lamps anyways, when you put it in unless you do it perfectly you can connect and disconnect and then reconnect which i think is very hard on lamps of any kind especially new ones. plus there hot and you might be more likely to drop it.
 

Mparn

Member
Update on our project.

Starting in February and completing in July, we have replaced approx. 5,000 lamps and decamped around 2,000. I know its early but here are some notes from the project.

Everyone seems to like the overall quality, consistancy, and level of lighting. It seemed a little bright for some at first, most of those rooms had several lamps out.

We've had a few issues; 1 lamp went bad, 2 lamps where the wire came loose, and 1 lamp was not put in correctly.

Our district has avgerged around 1.6 mil kWh per year over the last 3 years. We are on pace to end the year at 1.2 mill kWh. That should be around $40,000 in savings. I also adjusted the summer HVAC schedule, which also played a role in reduction.

Over the next month I will be replacing the exterior lighting. This includes; shoeboxes, flood lights, and wall packs. Each exterior fixture will have it's own surge protector.
 
Is there an update to this project? I work for a large school district and one of our new electricians ordered a lot of tombstone kits and type B lamps. We have never done type B lamps due to the mains voltage at the tombstone (non qualified personnel routinely are in the fixtures). Has this ever been a liability concern, safety issue or as a code issue and are we violating the UL listing by modifying the fixture with separate components vs a kit? Any input would greatly appreciated before we change direction in our retrofit program.
 

Dennis Alwon

Moderator
Staff member
The first thing I want to know is why there are unqualified people opening these fixtures?

Most kits that I have seen come with stickers that need to be installed but these are 120v units.
 
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