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#174090 - 01/26/08 07:56 AM metal halide fixtures
janderscu Offline
New Member

Registered: 01/25/08
Posts: 9
Loc: SC, USA
Hi,
I have four 400W metal halide fixtures at my church that run off of 220V. All wires from each fixture are tied together in one junction box and one 220V line is run back to a photocell mounted on the building. Over the past 5 years since the lights were installed, we have had to replace lamps numerous times and ballasts numerous times as well. I thought you could expect 2 or 3 years out of your lamps and even longer for the ballasts. My question is what could be causing this? I will tell you that I noticed that the original electrician installed a 110V photocell and is only switching one leg of the 220V, so the lights are always getting 110V. Could this be causing the problems? Thanks for any input.

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#174093 - 01/26/08 08:52 AM Re: metal halide fixtures [Re: janderscu]
sparkyinak Offline
Member

Registered: 07/08/07
Posts: 1286
Loc: Alaska
Welcome to the board. Ballasts is usually the last thing that goes on any type of fixture. I doubt the single leg switching will have anything to do with it unless the ballast or one of its leads were grounding out on something. Since the ballast replacement, how has the bulb life been since?

I do not mean any disrespect for asking the simplist questions, your posts has very limited info and I am well aware of wiring in churches.

Has the bulb been verified for proper mounting oriention?

Has all the connections been check to ensure good connections and proper wiring i.e. proper voltage tap?

Has the voltage at the fixture when the P.E. is closed been verified.

Has the capacitor been tested?

What it the open voltage at the socket?

How long is the run from the panel? What size wire is it that runs out to the light?

Has the been any adnormal power issuses in or around the Church?

To the best of your knowledge of the bulb/failure rate, is there any corralation with the failures with the weather? For example, When it rainy or adnormally hot, is there a higher rate of failures?

Is there any thing else on the circuit?

I would definently slave a relay off the P.E. to switch both legs. Someone cold get hurt.

details, details...
_________________________
"Live Awesome!" - Kevin Carosa

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#174096 - 01/26/08 11:51 AM Re: metal halide fixtures [Re: sparkyinak]
stlchuck Offline
Junior Member

Registered: 12/16/04
Posts: 5
Loc: St. Louis Mo.
Heres a couple of things to check;
Make sure the input voltage is matched to tap on the ballast.Ballasts frequently have multiple hookups (different wires or tabs to hook to)for different voltages,
if the voltage coming in is 240 volt and its hooked to the 208 volt tap, or vice versa the input is 208 volt and tapped to the 240 Volt tap either situation will shorten lamp and/or ballast life.
Check that the photocontrol (A.K.A. photocell or PEC)is hooked correctly, if the line and load wires are reversed, the PEC will stay closed (ON),all night,but will turn itself OFF and ON during daylight with the frequency of its time delay (PECs usually have a time delay of a couple of minutes to up to 10 or 15 minutes to stop car headlights and similar things from shutting them OFF).This will severly reduce life of lamps and ballasts.
Make sure that there are no 120 Volt loads tapped off the switched line to the lights.With the other line live all the time,the 400 Watt lights will be in series with the 120 Volt load, and this can burn out lamps due to the starting electrodes in the lamps still trying to fire even though the input voltage is less than 1/2.(Odds are probably slim of that one but it is a possibility, I know several years ago I beat my head against a wall quite a bit before I figured out that was occuring at one of my customers businesses).


Make sure the breaker is OFF to BOTH incoming lines before working on these fixtures,if only the PEC is OFF,there is still 120 Volts to the fixture.
When just changing lamps,there is 120 Volts on the screw shell of the lampholder even with the PEC OFF,so if someone touched the base of the lamp when screwing it in, they could be shocked and/or seriously hurt.

Chuck

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#174105 - 01/26/08 04:46 PM Re: metal halide fixtures [Re: stlchuck]
janderscu Offline
New Member

Registered: 01/25/08
Posts: 9
Loc: SC, USA
THank you Chuck and Sparky for all of the info and things to consider. That is what I was looking for. I have the original electrician coming out in a couple of weeks with his bucket truck to check the ballasts and connections so that should answer most of Sparky's questions, but I just wanted to get some ideas of other things I can get him to check out when he is there. I did have a different electrician come out recently and he said they never switch just 110V. They hook a PEC to a lighting contactor and switch the full 220V, but he was going to charge me $2600 to change it out and change out all 4 ballasts. So before I swallowed that much, I wanted to get more info.

Please keep the comments coming if anyone has other thoughts and I'll provide more feedback when I know more.

Thanks again.

Jason

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#174106 - 01/26/08 04:54 PM Re: metal halide fixtures [Re: janderscu]
janderscu Offline
New Member

Registered: 01/25/08
Posts: 9
Loc: SC, USA
Sparky, these are the answers that I know:

Since the ballast replacement, how has the bulb life been since?
I would say around 6 months.

Has the bulb been verified for proper mounting oriention?
What do you mean by this?


How long is the run from the panel? Approx. 150 ft.

What size wire is it that runs out to the light? I can check that. What is needed for that length?

Has the been any adnormal power issuses in or around the Church? At one point we had problems with incoming power from the power company, but they have fixed that over a year ago.

To the best of your knowledge of the bulb/failure rate, is there any corralation with the failures with the weather? For example, When it rainy or adnormally hot, is there a higher rate of failures? I havent's noticed any kind of correlation, but a good idea to pay attention to.

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#174108 - 01/26/08 05:39 PM Re: metal halide fixtures [Re: janderscu]
WESTUPLACE Offline
Member

Registered: 03/29/04
Posts: 252
Loc: Kingwood, TX USA
Bulbs are rated to burn base up, base down or all. Check and make sure the bulb rating matches the fixture. Also make sure the proper ballast is being used, I have found MH bulbs screwed into fixtures with SV ballast. ( they wanted the white light!lol) they will light, just not for long. The ballast needs to be matched to the wattage, and type of bulb. Robert

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#174110 - 01/26/08 06:03 PM Re: metal halide fixtures [Re: janderscu]
sparkyinak Offline
Member

Registered: 07/08/07
Posts: 1286
Loc: Alaska
 Originally Posted By: janderscu
Has the bulb been verified for proper mounting oriention? What do you mean by this?
Not MH bulbs are equal. Their performace and life expentancy can be shorten based on how the axis of the bulb is mounted in the fixture rather horizonally, at an angle or vertically. I was just looking through a bulb catalog. Some of the bulbs listed life expentancy is reduced by 25% and even 40%. It is dependent on the particular bulb and it axis orientation. typcial bulb life is 15,000 to 20,000 hrs. Presuming (never assume)12 hours a day on average for burn time, 3 to 4 years.

 Quote:
What size wire is it that runs out to the light? I can check that. What is needed for that length?
I would expect to see #10. at 150 feet. It is dependent of the entire length and how the wires are routed.
_________________________
"Live Awesome!" - Kevin Carosa

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#174113 - 01/26/08 07:20 PM Re: metal halide fixtures [Re: sparkyinak]
leland Offline
Member

Registered: 08/20/07
Posts: 856
Loc: Lowell area, Ma. USA
---particular bulb and it axis orientation---
I'm ashamed to admit it, But I've heard this and never paid it any mind (20+ yrs).
How is the orientation ID'd on the lamp?
#1 I'm having a similar problem at a gas station.(horizontal 400W MH)

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#174114 - 01/26/08 07:28 PM Re: metal halide fixtures [Re: leland]
frenchelectrican Offline

Member

Registered: 02/06/03
Posts: 938
Loc: Wi/ Paris France { France for ...
Leland the horztonal bulbs most will have either " U " marking or " Horz" marking but a catch here some old probe start MH's still use the POMB [ Post Ortation Mogual Base ]
the reason why the POMB base it have a pin so it will only go in so far and lock in the shell socket to keep the arc tube at correct postion because the arc tube some are slightly arc shaped so given performac there.

but down to the bottom line most impoart part is read the suffix on the bulb #'s like say U or Horz or BU or BD or H/45 [ horz to 45┬░ axis ]or other per manufacter spec called for.

Merci, Marc
_________________________
Pas de problme,il marche n'est-ce pas?"(No problem, it works doesn't it?)


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#174116 - 01/26/08 07:43 PM Re: metal halide fixtures [Re: frenchelectrican]
janderscu Offline
New Member

Registered: 01/25/08
Posts: 9
Loc: SC, USA
Been doing a little more poking around ...

Here is a link to the Sylvania product catalog. We are using the M400/Multi-kit .. page 49
http://dafnwebpd.sylvania.com/idmweb/doc...03683544&Page=1


Now here is a link to the Intermatic K4236C photocell we are using that is switching the 110 leg of the 220V going to the lights.
http://www.intermatic.com/Default.asp?action=subcat&sid=237&cid=119&did=45

Assuming the photocell is wired correctly (still need to check), can anyone see a problem with using the PEC with the M400 multikits (remember I have 4 fixtures connected)? It looks like to me we are pushing the current limit of the PEC. But seems like that would blow the PEC before having problems with the ballasts or lamps.

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