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rprevallet

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replacing a 2 tube ballast ( t-8's ) with a 2 tube ballast has always been the norm,:thumbsup: now to save money the VA i work for wants to remove all 1,2 & 3 tube ballast and replace them with 4 tube ballast's. this removes 1,2,3, tube ballasts from the shelves and makes space. :cry:and i'm told to use a 4 tube ballast for all app's, yet when showing the bean counters the different bulb configuations right on the ballast, it clearly shows a 4 tube ballast feeding a 3 or 4 tube Florissant and a 2 tube ballast shows it feeding a 2 tube or 1 tube florissant. does any one of my fellow brothers/sisters have any info or links that can hold water to my dilemma
 
rprevallet said:
replacing a 2 tube ballast ( t-8's ) with a 2 tube ballast has always been the norm,:thumbsup: now to save money the VA i work for wants to remove all 1,2 & 3 tube ballast and replace them with 4 tube ballast's. this removes 1,2,3, tube ballasts from the shelves and makes space. :cry:and i'm told to use a 4 tube ballast for all app's, yet when showing the bean counters the different bulb configuations right on the ballast, it clearly shows a 4 tube ballast feeding a 3 or 4 tube Florissant and a 2 tube ballast shows it feeding a 2 tube or 1 tube florissant. does any one of my fellow brothers/sisters have any info or links that can hold water to my dilemma
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I do know a 4 lamp ballast will light a single lamp, which you have probably figured out. I do not know if it has any impact on life of lamp or ballast, or if there is any impact on energy used.
 
hillbilly1 said:
Check the listing on the ballast, some are only listed for a certain number of lamps, but will operate fewer, but are not listed for the lower number.
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That is precisely what he is asking about. His employer/or other similar entity, is choosing to only stock the 4 lamp ballast and he is wanting to know if there is a problem with them only showing 3 or 4 lamp operation on the instructions, even though he knows they will work with less than 3.
 
Rapid start ballasts will not function for fewer lamps. Instant start ballasts will often operate fewer lamps than labeled however you violate the NEC and the lamps will be overdriven resulting in a little shorter lamp life. Driving one too few lamps is acceptable.
 
Since four lamp ballasts are the cheapest available from my supply house I am currently conducting my own test in my own house. I have two, two lamp T8 fixtures wired up with four lamp ballasts

No fires to report to date.

FWIW the guy I talked to at Sylvania tech support one time said you can always use fewer lamps with an electronic ballast. Of course there is no words to that effect on any ballast I have ever seen.
 
When you start capping leads you increase the ballast factor of the system. This increase the current and the wattage drawn. From an energy standpoint, it's a bad idea. It's going to cost you money. From a lamp warranty standpoint, you don't want want to overdrive them too hard. Most manufacturers don't recommend going over that 1.18 BF threshold and you certainly will driving one lamp with a four lamp ballast. You'll also create more heat doing this.

There's a reason why companies make ballasts for differing amounts of lamps.
 
Right next to the pallet of 4-lamp ballast, you should stock a 55 gallon drum of 8-port wagos. That way, you eliminate the shelf space taken up by all those different color wirenuts!
 
TNBaer said:
When you start capping leads you increase the ballast factor of the system. This increase the current and the wattage drawn. From an energy standpoint, it's a bad idea. It's going to cost you money. From a lamp warranty standpoint, you don't want want to overdrive them too hard. Most manufacturers don't recommend going over that 1.18 BF threshold and you certainly will driving one lamp with a four lamp ballast. You'll also create more heat doing this.

There's a reason why companies make ballasts for differing amounts of lamps.
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Some revisions of GE UltraMax uses individual lamp current regulation so the BF remains virtually constant when de-lamped or lamps fail, which they call Active Current Regulation.

(not all same model number ballasts are the same. Different product number with same model # can have different design with GE ballasts)

A typical four lamp 0.87BF ballast will run at 0.95 to 1.00 when running 3 lamps and 1.1 or so running 2. Many 4 lamp T8 ballasts do not allow more than 3 40W 5' T8s. Running four F40T8 will cause over-wattage and it can burn out.

The ballast label only shows a few typical examples of configuration. Some ballasts allow N-2, some don't. You often have to comb through manufacturers ballast catalog or request detailed datasheet from technical support to see all configuration. That said, some manufacturer sanctioned configurations do list BF as high as 1.3.

If you're going to do this, its important to print out the brochure and keep it on file. I recommend sticking with the same brand as well.
If you buy OSI ballasts and run OSI lamps at documented factory sanctioned configuration that deviates from warranty criteria, such as running at 1.3 BF, they have nobody to point fingers to and they're going to have hard time denying warranty as it proves you followed their own recommended practice.

Say you run OSI lamps with a 4-lamp GE ballast that permits running two lamps but runs at BF 1.3. When a bunch fails and OSI asks for ballast for warranty inspection (inspection of ballast for warranty claim investigation is often permitted by warranty contract) they'll likely say its not their problem that their lamps failed due to GE ballast running them outside of ANSI recommendations.
 
Smiley64 said:
Rapid start ballasts will not function for fewer lamps. Instant start ballasts will often operate fewer lamps than labeled however you violate the NEC and the lamps will be overdriven resulting in a little shorter lamp life. Driving one too few lamps is acceptable.
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This depends. Traditionally, programmed rapid starts were series wired.
GE's T8 proggies have been parallel for a while and the latest OSI's prog rapids are parallel as well. OSIs 4 lamp progs actually support 1-4 lamp operation. The reason for this move is that it increases group relamp interval. When one lamp goes out, one goes out with parallel. When one goes out in 3 lamp series layout, 3 goes out. Make sense? Your latter claim is also incorrect.

ActionDave said:
Since four lamp ballasts are the cheapest available from my supply house I am currently conducting my own test in my own house. I have two, two lamp T8 fixtures wired up with four lamp ballasts

No fires to report to date.

FWIW the guy I talked to at Sylvania tech support one time said you can always use fewer lamps with an electronic ballast. Of course there is no words to that effect on any ballast I have ever seen.
Click to expand...

No need for experiments.
http://ecom.mysylvania.com/onlineme...ogy-Application-Specification-Guide/#page=203

OSI QTP4x32T8 ISN officially permits 2 lamp operation, but uses 69W and runs lamps at 1.07BF (BEF 1.55) as opposed to QTP2x32 running two lamps running at 0.88 @ 59W (BEF 1.49)

It uses 17% more power, but overdrives the lamp at 21.6% more.

Now, the 1.20 BF 2 lamp high light ballast uses 78W and rated at 1.20BF

Don't use a configuration for which you can't locate written endorsement for liability reasons.


QTP 4x 32T8 ISN is a cookie cutter ballast and cheap.
QTP 2x32T8 ISH is lower volume and costly.

So, if higher output is desired and 1.07 as opposed to 1.20 is acceptable, 4x32T8 running is perfectly acceptable substitute. As a bonus, efficacy is better than 2 lamp normal output as evidenced by BEF I included.

Hope this make sense.
 
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