What happens if one installs a fluorescent tube or set of tubes of higher or lower wattage that the fisture is designed for? Do the results depend on whether the tubes are one-pin or two-pin? Do the results depend on whether the ballasts are magnetic or electronic? In particular, is it OK to use one of the newer low-wattage tubes in an older higher-wattage fixture?

 

Most case useally hard to defeat it unless you got old T12 ballast and try to run with T-8 Bulbs that useally not work very well and it will shorten the life both bulb and possiblty overheat the ballast.


No., They are not interchangeable between single and bipin format at all both have complely diffrent electrical charcticis { performace }

The magnetic ballast is pretty much old school stuff it slowly phasing out now and going with electronic it will not only save engery but little brighter to boot and very quiet as well.

Now for new lower wattage bulbs some of the ballast are not designed to take lower wattage bulbs at all.

Real cheap shoplights { typically about 10 € / $ 10 } typically are low power factor ballast and they can able take the reducted wattage bulbs but a major gotcha here is when you do use them they will have some diffucitally to lit up when cold espcally when colder than 50°F (10°C)

Also check the ballast label to see if they can take it as well.
Useally stamped on the ballast label

{ a 25watts 48 inch T-12 bulbs may work on some flourscent luminaires but not very many at all ditto with 34 watts T12 (4 footers) as well }

Merci,Marc

 

You obviously speak from experience with tubes rated at lower wattage than the fixture, and you didn't mention possible damage. I conclude that I can safely try it, but the tube may not light, may be dim, or may not start below 50 degrees F.

 

Calm G.,

I do speak from my experince from both North America and European side and I been in the bussiness for almost 20 years and I did see some crazy stuff along the way.

Now let get to the point the main issue is the ballast will take reduced wattage bulbs ??

The answer is yes it can however with older ballast it may overheat due they have to raise the secondary voltage to keep it lit.

That kinda common on very old ballast and some low power factor ballast they are designed to only give out so much of current running thru the bulbs.

Again check the ballast label to make sure they can use the reduced wattage bulbs
Side note here .,, pretty good percentage of electronic ballast have more leeway with reduced wattage bulbs but as I mention before the min starting tempture that usealy get them.

Merci,Marc