# Metal halide's and their capacitors



## jza (Oct 31, 2009)

I just did a big job which involved servicing multiple parking lot lights. I found that most of the time, it was just the bulb that needed replacing. If it wasn't the bulb, or if the bulb would light dim, I found that replacing the capacitor was the fix.

That being said, is there anything wrong with just replacing the capacitor? It's a lot faster than replacing the capacitor and ballast together.


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## BBQ (Nov 16, 2010)

jza said:


> That being said, is there anything wrong with just replacing the capacitor? It's a lot faster than replacing the capacitor and ballast together.


Well there is when you find one of your guys stole all the capacitors out of compete ballast kits but never ordered replacements so now I have a bunch of ballasts without caps. 


But other than that, no not a problem.


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## jza (Oct 31, 2009)

BBQ said:


> Well there is when you find one of your guys stole all the capacitors out of compete ballast kits but never ordered replacements so now I have a bunch of ballasts without caps.
> 
> 
> But other than that, no not a problem.



LOL, it's funny you should mention that...

Ballast and cap kit, $100, in stock.
Capacitor, $10, special order.

Eventually I'll get around to ordering those two capacitors.


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## D-Bo (Apr 15, 2012)

ive always replaced bad caps only because i have a surplus of them at my disposal but the last time this topic was brought up the general consensus was its more economical to replace the whole ballast kit. to each their own. if you worked on exterior lighting a few times a year i could see doing the whole kit. if you're responsible for hundreds year round im only fixin whats broke


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## jza (Oct 31, 2009)

D-Bo said:


> ive always replaced bad caps only because i have a surplus of them at my disposal but the last time this topic was brought up the general consensus was its more economical to replace the whole ballast kit. to each their own. if you worked on exterior lighting a few times a year i could see doing the whole kit. if you're responsible for hundreds year round im only fixin whats broke


Why is it more economical to replace the ballast as well? Because you're there?


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## Sparky J (May 17, 2011)

jza said:


> Why is it more economical to replace the ballast as well? Because you're there?


Usually. I will check the bulb or photocell if it has one and replace as needed but generally if I need to replace the capacitor I just put in the whole kit. It sucks when the customer thinks you fixed it, has paid and then the ballast craps out in like a week from changing only the cap or starter. I just change it all if needed as my customers want it to work and they pretty much always want the complete kit swapped. Some even supply their own kits/bulbs no biggie.


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## jza (Oct 31, 2009)

Sparky J said:


> Usually. I will check the bulb or photocell if it has one and replace as needed but generally if I need to replace the capacitor I just put in the whole kit. It sucks when the customer thinks you fixed it, has paid and then the ballast craps out in like a week from changing only the cap or starter. I just change it all if needed as my customers want it to work and they pretty much always want the complete kit swapped. Some even supply their own kits/bulbs no biggie.


Ya, but what's to say the ballast will fail in a week after changing the capacitor? You could change the bulb, and the ballast could go within a week from that. Where do you draw the line?


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## RePhase277 (Feb 5, 2008)

The "ballast" is a combination of capacitor and transformer. Having said that, in all my lighting jobs (I do lots of parking lot lighting), rarely have I found the transformer to be bad. I mean almost never. In fact, the only time I can think of in recent history that I found a bad transformer, was because someone wired to the wrong tap voltage.

I even took a transformer out of a light that had caught fire. It was in bad shape but still functional. Consequently, I have gone from buying ballast kits to just buying capacitors.


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## Sparky J (May 17, 2011)

No I'm saying that generally I change the whole ballast kit but because thats what my clients want (yes I've asked). It's the same with the light bulbs if I change a ballast I change the bulb too. Check the timer photocell etc. Just good to do in my opinion. But you know what they say about opinions....
As a pretty much one man band without a bucket truck it is more beneficial to my clients for me the do it this way. BTW. Most of the ones I work on are lower ones like 12-20 feet high so I don't need a bucket or lift that often.
And also I am not knocking your way, my way is just different that's all.


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## D-Bo (Apr 15, 2012)

jza said:


> Why is it more economical to replace the ballast as well? Because you're there?


I don't necessarily think it is unless I'm in the bucket and I don't want go back up in a month to replace the rest. That being said if one out of 100 lights is out on one of the plants I'm employed at I'm changing the cap that's it. Every situation is different


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## jza (Oct 31, 2009)

InPhase277 said:


> The "ballast" is a combination of capacitor and transformer. Having said that, in all my lighting jobs (I do lots of parking lot lighting), rarely have I found the transformer to be bad. I mean almost never. In fact, the only time I can think of in recent history that I found a bad transformer, was because someone wired to the wrong tap voltage.
> 
> I even took a transformer out of a light that had caught fire. It was in bad shape but still functional. Consequently, I have gone from buying ballast kits to just buying capacitors.


This is what I'm finding as well. I guess I'll report back and see how the 3 lights with new caps and old ballasts hold up.


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## retiredsparktech (Mar 8, 2011)

jza said:


> Ya, but what's to say the ballast will fail in a week after changing the capacitor? You could change the bulb, and the ballast could go within a week from that. Where do you draw the line?


Your nose would know if the ballast was ready to fail.
Most of my experience has been with with HPS. The fixture rebuild kit would cost as much as a complete replacement fixture. Generally the starter pack, would be the problem. Once in a while, the cap.
I'm refering to inside hi-bay lighting.


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## nervous (Nov 13, 2012)

To me, each light is gonna be different. One light will have a bad capacitor and a stinky,ugly ballast. I will install a ballast kit. Another light will have a bad capacitor and what looks and smells like a newer ballast and I will change only the capacitor.


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## micromind (Aug 11, 2007)

InPhase277 said:


> The "ballast" is a combination of capacitor and transformer. Having said that, in all my lighting jobs (I do lots of parking lot lighting), rarely have I found the transformer to be bad. I mean almost never. In fact, the only time I can think of in recent history that I found a bad transformer, was because someone wired to the wrong tap voltage.
> 
> I even took a transformer out of a light that had caught fire. It was in bad shape but still functional. Consequently, I have gone from buying ballast kits to just buying capacitors.


Same here. Very rarely do I ever see a transformer burnt up. Almost always the capacitor. 

Caps are pretty easy to come by, one of the local wholesalers stocks most sizes. Grainger stocks some of them too.


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## BBQ (Nov 16, 2010)

I find lots of burned up core and coil ballasts. If a new lamp does not work and the ballast looks toasted I change them.


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## hardworkingstiff (Jan 22, 2007)

Anyone using the electronic ballast?


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## BBQ (Nov 16, 2010)

hardworkingstiff said:


> Anyone using the electronic ballast?


Only in some indoor fixtures, I have not seen one in an outdoor fixture and unless it was potted I dont think they would last.


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## HARRY304E (Sep 15, 2010)

BBQ said:


> Well there is when you find one of your guys stole all the capacitors out of compete ballast kits but never ordered replacements so now I have a bunch of ballasts without caps.
> 
> 
> But other than that, no not a problem.


Thats always fun when you pick up ballasts and open the box on site to find the capacitor is missing..


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## BBQ (Nov 16, 2010)

HARRY304E said:


> Thats always fun when you pick up ballasts and open the box on site to find the capacitor is missing..


Exactly.

I went to a site where we keep a gang box full of lamps and ballasts for that site. We do a monthly lighting service there. 

Anyway I open the gang box and see a few boxes marked 'missing cap'.

Nice they labeled them, pain in the ass that they did not order new ones to replace them.


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## Cletis (Aug 20, 2010)

jza said:


> Ya, but what's to say the ballast will fail in a week after changing the capacitor? You could change the bulb, and the ballast could go within a week from that. Where do you draw the line?


What if they are 100 ft stadium light 1500's. do you all have the same approach?


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## Amish Electrician (Jan 2, 2010)

This is more of a 'business' question than a technical one. How many tims do you want to go up the pole?

Me, I like to do it once, twice MAX. Remember, any call-backs are on your dime, and the customer rightly expects your stuff to last at least a year.

HID's are almost always located high up, in difficult to reach, remote locations. You can spend all day walking back and forth to the LOTO point, waiting for the lights to cycle, etc. 

So ... do you want to replace just the capacitor, only to have the igniter crap out a week later? Or the ballast itself?

OK ... design time ... I'd say the first thing you need at each pole is a fuse on every 'hot' wire. That helps you locate amd isolate faults. You also want a local means of disconnection - so you need not walk three miles to the panel every time. Perhaps some sort of 'plugs' inside the handhole.

You also want an accessible way to bypass the photocell. It gets tiring searching out the photocall and climbing over the roof.

Quick-connects on the ballast also make life easier - and might also qualify as your 'disconnecting' means. 

Simple procedure: Power things up, and see who's "dark." Replace ub; still dark, verifypower is getting there, then replace ballast AND bulb. Take old ballast to shop and bench-test to your hearts' content.


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## stlchuck (Jan 9, 2009)

Over the last 20+ years i have probably replaced hundreds of capacitors and quite a few igniters, I have never had to go back and replace the transformer afterwards. 
When I check a ballast, I will test the open circuit voltage first, (I use Advances pocket guide to HID lighting, it has the test limits in it). I then test the secondary short circuit current, if there little or no current, then the cap is completely bad, (in that case the open circuit voltage usually reads low also).
If the current reads below the spec, the cap is weak, but not completely gone (this is often the cause of dim and extra blue-ish light output of metal halide lamps).
In either case the cap needs replacing, so I'll power down and examine the transformer, if it shows signs of overheating I will replace it, but that rarely happens. A capacitor is usually quick and easy to change, and they are frequently cheaper than the lamp.
I do the same checks on ballasts with igniters,if the OCV & SCC are good but a known good lamp won't start, the igniter is the issue.
I don't fault someone for changing the whole kit if they prefer, I know that accessing this type of lighting is often a challenge, and having the individual components on hand is not always practical, in my case, my service truck is a 55' ladder truck and I carry a large amount of lighting stock on it, so my service habits will be a bit different than the guy that has to rent a piece of equipment and load up or buy what parts he needs for the job.


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## n5i5ken (Jun 5, 2011)

*Field lighting*

usually 50 feet up plus I change out all. Customer does not like it when we change lamp-- week later we are back for the cap and a week later we are there again.. They usually say this trip up is free BOSS DONT LIKE THAT.


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## Wingman2002 (Jan 2, 2011)

For years we tried to replace what we thought was wrong. We could afford to make a trip back if the light stopped working again. Now it cost to much money to make the extra trip. If they want a price upfront........they are buying the kit!!


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## dthurmond (Feb 7, 2011)

We have about 20 parking lot lights about 30 feet up . We have to rent a lift to change the ballast so I usually change everything . I have found numerous ballast totally fried in these lights . It is usually after a real bad lighting storm .


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## bigpapa08 (Nov 19, 2012)

The last company I worked for the bulk of what we did were parking lot lights and other exterior lights. Generally if the ballast looked good I would just replace the cap. If it smelled and looked smoked then it got the whole kit. Now one of the other guys would change the whole kit regardless. He said that by installing a new lamp and cap, and not changing the ballast would cause the ballast to go bad, if it wasnt already.


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## energylightbulbse (Aug 3, 2012)

Hi cletis,

I agree with you, you will have to change the approach.


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## bobelectric (Feb 24, 2007)

Any one have secrets to change a "shoebox" fixture ballast?


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## RePhase277 (Feb 5, 2008)

bobelectric said:


> Any one have secrets to change a "shoebox" fixture ballast?


Open the fixture... replace ballast...:whistling2:


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## Cletis (Aug 20, 2010)

jza said:


> I just did a big job which involved servicing multiple parking lot lights. I found that most of the time, it was just the bulb that needed replacing. If it wasn't the bulb, or if the bulb would light dim, I found that replacing the capacitor was the fix.
> 
> That being said, is there anything wrong with just replacing the capacitor? It's a lot faster than replacing the capacitor and ballast together.


I do it all the time. 99.9% of the time it's either the bulb or capacitor. Remember, Those two are "Wearable" parts. The actually ballast is not really "Wearable". The only reason ballast (transformers) fry is heat, lightening. The heat is when capacitors start to go bad and overcompensate with voltage fluctuations causing an antipole thermal cascade back into the transformer (ballast). 

So, carry a bunch of round (round fits in oval, oval not in round) capacitors and bulbs and your ready for business. 

Note: Quality is extremely important so buy good capacitors!!!


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## NacBooster29 (Oct 25, 2010)

bobelectric said:


> Any one have secrets to change a "shoebox" fixture ballast?


Don't drop it on your head


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## frenchelectrican (Mar 15, 2007)

bobelectric said:


> Any one have secrets to change a "shoebox" fixture ballast?


 
There are few ways to deal with those dammed shoeboxers ., but #1 rules is never stand below the shoebox luminaire ya never know what will drop down when you open up the lens door if they have it or reflector lens screw off and drop it down.

BTW those larger shoebox are no lightweight luminaires at all they can weight much as 50 KG ( apx 110 lbs ) some case more.

Merci,
Marc


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## delaware74b (Jan 29, 2012)

I see more cap failures than ballast failures. A local mall has approx 70 1000w MH and we have a 'standard' procedure when servicing them. Any fixture that gets opened for a lamp or socket failure gets the cap tested. The normal 1000w cap is a 24uF with a 3% tolerance. If a cap reads 22uF or less, it gets replaced. A borderline bad cap causes a low strike, burns out the start probe in 100 hours or less.

The only bad ballasts I have seen were the result of either a nearby lightning strike or getting wet. The Cooper GLA's have a problem with water leaks in the top corner where the ballast is mounted. Something about a 480V ballast and water usually letting out all the factory installed smoke......


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