# Metal Halide Issues



## telsa (May 22, 2015)

You've got a multi-vibrator circuit.

I leave it for you to study up -- Wiki has a work up on it.

Come back with your questions. 

I can't possibly cover all that material in a forum post. :no:


----------



## daveEM (Nov 18, 2012)

Fixture make and number?


----------



## emtnut (Mar 1, 2015)

Mr.Awesome said:


> Both circuits are wired to a contact controlled by a photocell.
> 
> There isn't an issue every morning, just on occasion.
> 
> ...


What contactor are you using ?

When you have the issues, are they temperature related ?

Your Voltage readings... are these readings when the light isn't on ?


----------



## Big John (May 23, 2010)

Dumb question: Are you assuming the distributor supplied lamps are correct or did you check the nameplate to see they were the right ANSI class?

Because I would start with the lamps. Swap all three to another brand rated for that fixture, go from there.


----------



## Mr.Awesome (Nov 27, 2015)

Telsa, peaked at the wiki page. Way over my head. 2ill need more time to read up on that.

Dave, will have to get back to you on a model number.

Temperature crossed my mind. They didnt start acting up until the temperature dropped. My company uses these lights all the time though without issue.
120v at lights while on and working.
Allen bradley contact. Proper ratings.
I opened the lights and crossed checked the bulbs with the ballasts. Good there.

Thank you all for the responses thusfar.


----------



## Awg-Dawg (Jan 23, 2007)

If the lights are new, I would start eliminating things. You said wires were good, I'd lose the contactor first. The PC is more than likely adequate for the load. 

I gotta tell you tho, it seems like it might be a wiring problem.

With the load you have on each circuit, you could have a neutral issue that isn't showing up.

I'd also put them on one circuit, unless you have a reason to put them on two.


----------



## telsa (May 22, 2015)

Mr.Awesome said:


> Telsa, peaked at the wiki page. Way over my head. 2ill need more time to read up on that.
> 
> Dave, will have to get back to you on a model number.
> 
> ...



You've left off the critical details that figure huge:

Wire size.

Distance from the load to the panel.

I'll take a wild guess and assume that these dinky loads merited only #12 AWG.

I'll further take a wild guess that they are not at all close to the panel.

If this is the case ( both true ) then you've crafted a multi-vibrator.

You can no longer consider the field conductors to have nearly zero resistance. 

They are now active components in the circuit and are causing oscillations that perplex 99.7% of electricians.

One could have a 40-year career and never run across a multi-vibrator circuit.

( Outside of every PC and chip that has ever been. The chip's clock is a multi-vibrator circuit. They are now EVERYWHERE in our digital world. )

The moment you start seeing *Flip-Flop* behavior - -a light bulb should fire off in your head.

Ultimately, if this is what you are dealing with, your only cure is to replace your field wiring. For it needs to be upsized... at least one bump.

The distance from the panel to the load is _extremely_ relevant.

You are in no position to re-engineer the fixture or the lamp.

All of the above is said in the belief that you've pounded out all of the basics....

Double check them one last time, with a fresh mind.

BTW, I see a constant stream of puzzled electricians whenever these situations pop-up. They are normally once in a career events. 

I'm embarrassed to admit how long it took me to dope out the first time I ran across one. For they are not in any text oriented towards electricians.

They are covered in the course material given to electronics engineers, instead. That's where I gained my insight. 

BTW, it, the problem, had stumped every high time pro. That's why it was dropped into my lap.


----------



## emtnut (Mar 1, 2015)

telsa said:


> You've left off the critical details that figure huge:
> 
> Wire size.
> 
> ...


I think you're saying these lamps have a high start-up current :thumbup:


----------



## telsa (May 22, 2015)

emtnut said:


> I think you're saying these lamps have a high start-up current :thumbup:


That's the Cliff's notes version. :laughing:


----------



## ELECTRICK2 (Feb 21, 2015)

Mr.Awesome said:


> Telsa, peaked at the wiki page. Way over my head. 2ill need more time to read up on that.
> 
> Dave, will have to get back to you on a model number.
> 
> ...


 I would start with bypassing the PEC and contactor. Put a switch in to control the 3 lights on one circuit. Turn it on and see if they come on. If they do, turn them off and then back on right away. Repeat. If telsa is right you should get a failure, if not....


----------



## Big John (May 23, 2010)

Awg-Dawg said:


> I gotta tell you tho, it seems like it might be a wiring problem.
> 
> With the load you have on each circuit, you could have a neutral issue that isn't showing up....


I hear ya, but I lean completely the other direction: 

If he's got a hard steady 120V at the fixture (and it sounds like he does) then this is a problem with the ignitor circuit. That's why I would start with lamps, because it's the easiest check.

But I'll go one better: Next time you have a fixture out, put a decent sized load right at the fixture leads, like a 300W bulb in a clip-on test socket. If it lights, and you don't see any voltage fluctuations you know this is a fixture problem.


----------



## Mr.Awesome (Nov 27, 2015)

Alright gents, more info.
Fixtures are Lithonia TWR2 250M 120/347 LPI CSA
Separate circuits are being used because A will have two more lights added to the circuit when the sheet metal guys finally finish the exterior siding, and this will put us over our 12A limit. 15A circuit is being used because the jman said so.
20' of #12 runs to a j box from the panel, out of it is a 15' run of 14/2 feeding B and C, and maybe 30' of 14/2 feeding A.
Monday I have to swing by our shop so I'm grabbing fresh bulbs to try, and I think I'm going to try the switch and 300W bulb ideas. Currently, the jman had a walkthrough today and asked that the photocell be bypassed so the lights are burning continuously to be monitored. With the switch, should the lights follow a pattern or is this a random act of working/not working?
I'm absolutely not opposed to the idea that I just built one of these vibrator circuits, I just don't understand how. This method is how exterior lighting circuits are dealt with on every site I've been on, and no issues.
Would it be possible to speed up the "flip flopping" and use colored bulbs to make the building look festive at least?


----------



## emtnut (Mar 1, 2015)

Mr.Awesome said:


> Alright gents, more info.
> Fixtures are Lithonia TWR2 250M 120/347 LPI CSA
> Separate circuits are being used because A will have two more lights added to the circuit when the sheet metal guys finally finish the exterior siding, and this will put us over our 12A limit. 15A circuit is being used because the jman said so.
> 20' of #12 runs to a j box from the panel, out of it is a 15' run of 14/2 feeding B and C, and maybe 30' of 14/2 feeding A.
> ...


Here ya go ... Merry Christmas :laughing:


----------



## telsa (May 22, 2015)

Mr.Awesome said:


> Alright gents, more info.
> Fixtures are Lithonia TWR2 250M 120/347 LPI CSA
> Separate circuits are being used because A will have two more lights added to the circuit when the sheet metal guys finally finish the exterior siding, and this will put us over our 12A limit. 15A circuit is being used because the jman said so.
> 20' of #12 runs to a j box from the panel, out of it is a 15' run of 14/2 feeding B and C, and maybe 30' of 14/2 feeding A.
> ...



Here's the issue with CWA and other halide ballasts: They take drastically more starting current than the nominal wattage.

This surge in draw is quite brief. It's so brief that it never shows up as an issue with the wire or the circuit breaker.

It's just that if the wire is small enough and long enough a CWA can get choked off enough that it can't Q U I T E make it over the hump. It won't pulse.

Instead, its buddy fired off.

Then, after you cycle it off... the next time the fixtures flip -- what had been off is now on, what had been on is now off.

The very long field wiring turns into an RL (resistance-inductance) circuit element.

%%%

In the case at hand, your distances are modest.

Yet, you managed to run as little as #14-2.

Your first lesson: never, ever, ever, run circuits outside (site lighting) without bumping them up ( #14 => #12 if not #10 ) 

Such runs are the LAST place you should attempt to "value engineer' a job.

We have a steady stream of posters complaining about their own under-sized craft work. Since they ran cable, they are not interested in hearing the ugly truth: start over.

&&&

Back to your circuit, for a brief moment, your fixtures are fully capable of drawing 750 Watts. ( 3x nominal Wattage )

You are trying to heat it up at the same time you're trying to get it to pulse. 

#14 is just too small.

In a commercial setting, #12 is the minimum. And you can bet that the fixture designers expected that minimum.

But, as I wrote, you must clean up all other issues before you start chasing this matter down. I'd look everywhere else, first.

Be doubly sure that your neutrals are absolutely sweet.


----------



## telsa (May 22, 2015)

As for a general point of knowledge (an essential) :

Study up on the 555 integrated chip. 

This timer chip is a multi-vibrator in a chip.

About 100,000,000+ are made each year, IIRC.

You guessed it, timers are needed everywhere you turn.

This fella costs less than a buck if you bought in real volume.

Yes, it has its own Wiki page.

It's actually hard to built an electronic circuit of consequence and not use a 555.

Heh.


----------



## Southeast Power (Jan 18, 2009)

Ok Mr. vibrating circuit.
His runs are #14.
His longest run is 30'
Second run 20' 
Last run 15'

His 250 watt load is maybe but highly doubtful 10x the load on start.

Assume a WYE system

What would be the running current on the neutral assuming the loads are equal at about 2.5 amps per phase?


----------



## Southeast Power (Jan 18, 2009)

telsa said:


> Here's the issue with CWA and other halide ballasts: They take drastically more starting current than the nominal wattage
> 
> Be doubly sure that your neutrals are absolutely sweet.


Would theory show that he could lift the neutrals off of the neutral bar and wire them together under one wirenut?

I really have a problem with your voltage drop theory on a circuit with three home runs and and the longest one being 30' with 2.5 amps of load on it.

Btw, no one has suggested using 208 volts, if permitted, for this circuit.

I'm with the lamp camp on this one.


----------



## Southeast Power (Jan 18, 2009)

telsa said:


> As for a general point of knowledge (an essential) :
> 
> Study up on the 555 integrated chip.
> 
> ...


You are just tryimg to see how much smoke you can blow up this guys azz aren't you.:laughing:


----------



## Big John (May 23, 2010)

jrannis said:


> You are just tryimg to see how much smoke you can blow up this guys azz aren't you.:laughing:


 You just aren't smart enough to understand how an extremely simple and common lighting circuit is actually secretly a timed oscillator!


----------



## MTW (Aug 28, 2013)

Big John said:


> You just aren't smart enough to understand how an extremely simple and common lighting circuit is actually secretly a timed oscillator!


This was the same guy that said we needed to understand quantum physics / wave mechanics to understand a open neutral over voltage on an MWBC.


----------



## Big John (May 23, 2010)

Every good electrician knows that if you ever see lights brightening in a way that suggests an open neutral, the very first thing you do is call the chaps over at the CERN particle accelerator so they can explain the cause of the problem.


----------



## MTW (Aug 28, 2013)

Big John said:


> Every good electrician knows that if you ever see lights brightening in a way that suggests an open neutral, the very first thing you do is call the chaps over at the CERN particle accelerator so they can explain the cause of the problem.


:laughing::laughing::laughing::laughing::laughing:


----------



## Southeast Power (Jan 18, 2009)

Big John said:


> You just aren't smart enough to understand how an extremely simple and common lighting circuit is actually secretly a timed oscillator!


Oh. and you think you are going to school me on the 555 multi-vibrator chip?

Nice try. :laughing:


----------



## Vintage Sounds (Oct 23, 2009)

Big John said:


> Every good electrician knows that if you ever see lights brightening in a way that suggests an open neutral, the very first thing you do is call the chaps over at the CERN particle accelerator so they can explain the cause of the problem.


 Yeah but you can't think about calling up CERN until you blame Red China, Muslims and "Barry Soetero" for collaborating with the MSM to make it appear that the lights brightening is entirely normal and not the doing of an international syndicate whose intent is to blind the public so they can accomplish their insidious agenda.


----------



## Mr.Awesome (Nov 27, 2015)

Thank you for the simple break down telsa. Neutrals were inspected and happy.
So to sum this up...
Monday I'll try new bulbs, bypass the photocell with a toggle switch to flip them on and off, and if the issue persists, suck it up and bump my bx up a size.


----------



## Big John (May 23, 2010)

Mr.Awesome said:


> ...Suck it up and bump my bx up a size.


 What does this mean? Inncrease your conductor size?


----------



## gryczewskip (Oct 27, 2015)

Wire size I would assume

Sent from my E6782 using Tapatalk


----------



## gryczewskip (Oct 27, 2015)

LED

Sent from my E6782 using Tapatalk


----------



## ELECTRICK2 (Feb 21, 2015)

Mr.Awesome said:


> Alright gents, more info.
> Fixtures are Lithonia TWR2 250M 120/347 LPI CSA
> Separate circuits are being used because A will have two more lights added to the circuit when the sheet metal guys finally finish the exterior siding, and this will put us over our 12A limit. 15A circuit is being used because the jman said so.
> 20' of #12 runs to a j box from the panel, out of it is a 15' run of 14/2 feeding B and C, and maybe 30' of 14/2 feeding A.
> ...


Forgot to ask before, when a light turns on does it stay on?
A bad lamp will cycle on and off


----------



## Mr.Awesome (Nov 27, 2015)

Yes john, my conductor size. Excuse the terminology.
Electrik, yes they do stay on. I will be surprised if the bulbs are all thats wrong. Not that I've been at this job for a long time, but I've never seen this issue and never seen 100% of the bulbs bad out of the box.


----------



## Big John (May 23, 2010)

If you're not seeing voltage problems at the fixture leads, then re-installing the branch circuit would be the last thing I'd do, no kidding.

If the fixture is getting proper voltage there's nothing else you can do to make it any happier.

I'd try a lamp, and if that doesn't work, I'd either replace the ballast or the entire fixture.


----------



## Mr.Awesome (Nov 27, 2015)

John, thats the jmans plan. Monitor them for a few days, if the problem persists, rip them down and send them back.


----------



## Helmut (May 7, 2014)

My money is on cheap or bad bulbs. Change all 3 and your problem will go away.

Either that or the electrons coming from the plant need charging.


----------



## ELECTRICK2 (Feb 21, 2015)

Mr.Awesome said:


> Yes john, my conductor size. Excuse the terminology.
> Electrik, yes they do stay on. I will be surprised if the bulbs are all thats wrong. Not that I've been at this job for a long time, but I've never seen this issue and never seen 100% of the bulbs bad out of the box.


If they stay on its not the lamps
When it gets confusing go back to KISS
Keep it simple stupid.
Not calling you stupid, that's just the phrase.
By operating the lights with just a switch you eliminate a lot.
I like your attitude, let us know..


----------



## sparkywannabee (Jan 29, 2013)

I have been replacing metal halides with LED's for a while now, Acuity, which I think is Lithonia, makes these awesome 250W equivalent, only use 80W, floods. Better light, dos not have to cool to reignite, can't beat em. Prices on the fixtures are a lot closer as well.


----------



## sbrn33 (Mar 15, 2007)

sparkywannabee said:


> I have been replacing metal halides with LED's for a while now, Acuity, which I think is Lithonia, makes these awesome 250W equivalent, only use 80W, floods. Better light, dos not have to cool to reignite, can't beat em. Prices on the fixtures are a lot closer as well.


worthless without a part number or at the very least a pic.


----------



## telsa (May 22, 2015)

sbrn33 said:


> worthless without a part number or at the very least a pic.


Google is your friend.

http://milehighledsystems.com/lithonia_led.html


----------



## Mr.Awesome (Nov 27, 2015)

LED was explored but the building's GM didn't want to go that route for whatever reason.
Update for you guys. Shop didn't have any bulbs kicking around. Lights were burning 24 hours all weekend without issue. Plopped a toggle switch on in place of the photocell and every few minutes flipped them on and off. All three worked 100% of the time. Wired the photocell back in and we'll see how they do this week.


----------



## ELECTRICK2 (Feb 21, 2015)

Mr.Awesome said:


> LED was explored but the building's GM didn't want to go that route for whatever reason.
> Update for you guys. Shop didn't have any bulbs kicking around. Lights were burning 24 hours all weekend without issue. Plopped a toggle switch on in place of the photocell and every few minutes flipped them on and off. All three worked 100% of the time. Wired the photocell back in and we'll see how they do this week.


I assume the toggle switch was operating the contactor. If so, you've eliminated most of the possibilities. 
Just a thought, is there any lights in the area of your PEC that might be affecting it?


----------



## Mr.Awesome (Nov 27, 2015)

Yes, operating that contactor. The photocell is located a couple of feet above the lights, which project outward and not upward. If the photocell was picking up on light from the lights themselves though, would that not cause it to on and off? Therefore killing all the lights and not just one or two at a time?


----------



## Mr.Awesome (Nov 27, 2015)

Well, photocell went back in on Monday, wonky lights on Tuesday, then no issues.
Jman is siding with "one of those things" and we're leaving it until they act up again.
This one will bug me for awhile!


----------



## ELECTRICK2 (Feb 21, 2015)

Mr.Awesome said:


> Well, photocell went back in on Monday, wonky lights on Tuesday, then no issues.
> Jman is siding with "one of those things" and we're leaving it until they act up again.
> This one will bug me for awhile!


Never been a fan of "one of those things".
At this point with me it would become personal. I would have to figure it out. the reason I brought up the ambient light is because if there is ambient light affecting the photocell the HID lights will turn on and off at different times, they cool off and restrike at different times. This would account for your scenario of 2 lights on the same circuit and 1 is on and the other is off. With the switch you proved the circuitry and contactor works. The lights all work, as you proved by leaving them on for a while. That leaves the photocell. If I remember right you also proved the photocell works by putting your glove over it. The only variable left (that I can think of) is the ambient light. Take into consideration what the conditions were at the time the system failed. Intermittent cloud cover could be the cause. I love it when an apprentice wants to know. Let me know what happens.....


----------



## Mr.Awesome (Nov 27, 2015)

I've been asked to leave them alone until they act up again. I'm sure I'll be back up there one day though so I will definitely let you know how things go. Added two more lights onto one circuit so we'll see if they give us grief as well.
I'm also not opposed to your ambient light idea, but my glove is my photocell turner onner which completely blocks out light. Several times using my glove the lights have acted up.


----------



## Mr.Awesome (Nov 27, 2015)

Wanted to throw this out there for you guys, especially you Electrick.
Swayed my jman to order fresh bulbs just before christmas. Popped them in, and a month later there hasn't been a single issue. Got a crappy batch of bulbs I guess. What I don't understand now is what is going on inside the bulb itself to cause them to light randomly.


----------

