# 40 watt ballast ok for 36 watt tube?



## licklick (Feb 26, 2010)

as above will be changing uv bulbs soon fromm repti glo to arcadia 12%,thing is though the retiglo is 40 watts(48" tube) and arcadia is 36 watts (i think)do i have to change my ballast again(went from 15 to 40 watts ) or do i need a lower wattage starter?any help will be nice.
thanks nick.


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## jef_b (Mar 7, 2010)

No dude, the fixture is rated for up to 40 W, as long as you do not exceed that you should be fine... just like a regular light socket, the ceramics are rated for up to 660W and most people put 40 or 60 W bulbs in them.


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## lee young (Oct 14, 2009)

Im pretty sure thats not the case, UV bulbs work very differently to incandescent bulbs, using a higher wattage starter is more than likely going to fry the bulb, or atthe least give out too much/not enough UV. You'd be best off asking an electrician.


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## jef_b (Mar 7, 2010)

Actually I use lower wattage bulbs and higher wattage fixtures all the time. As stated before, the W is the highest you can use in that particular fixture. It is not going to effect the amount of UV output, as the ballast does not control that. I have never fried out any bulb by putting it in a higher rated fixture. I have, however, had the experience of blowing a bulb by putting it in a fixture that was rated too low for the bulb. Don't worry 4W is not going to hurt either, unless you were using a 44W bulb in a 40W ballast.


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## lee young (Oct 14, 2009)

The rated wattage on the fixture is the power it puts out, nat a rated maximium. Normal bulb holders have a rated maximum, but theyre just an electrical connection, a UV starter gives out a constant current.

A good analogy is that you could use 50W speakers with a 100W amp, but they would die a lot quicker. To obtain the stated levels of UV and maintain good bulb life you need to correctly match the starter and the tube.

http://home.howstuffworks.com/fluorescent-lamp6.htm


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## jef_b (Mar 7, 2010)

To be honest I just read that article that you posted and read nothing about wattage, or causing lights to have an early life due to an under wattage. It does, however state that the ballast controls the voltage allowed to pass through the circuit, which causing the differing charge that lights the tube. Also, I am still confused as to how a bulb that has a specific UV rating can give off more UV?? Not trying to argue the point, but I have never had a prob with using a lower rated bulb in any fixture I have used, fluorescent or incandescent.... maybe I am just lucky??


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## jef_b (Mar 7, 2010)

lee young said:


> A good analogy is that you could use 50W speakers with a 100W amp, but they would die a lot quicker. To obtain the stated levels of UV and maintain good bulb life you need to correctly match the starter and the tube.
> 
> HowStuffWorks "How Fluorescent Lamps Work"



Also there is a huge difference here! 50W vs 4W!!


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## lee young (Oct 14, 2009)

I know there is a huge difference, I was merely pointing out that your statement of "No dude, the fixture is rated for up to 40 W, as long as you do not exceed that you should be fine... just like a regular light socket, the ceramics are rated for up to 660W and most people put 40 or 60 W bulbs in them." is not true.

Ballasts for UV tubes have to be more or less equal to the tube. In this case as the difference is only 4W, you probably wouldn't notice any detrimental effects, but try putting a 15W tube in a 40W starter and you'll start a fire.

The arcadia ACUP36 starter is designed for both the 36W (40") and 38W (48") tubes, so your 40W starter should be ok for a 36W tube, but there was a thread on here last week about using the wrong starters for tubes, and a few people have had fires due to tubes overheating because of too much power going through them.


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## jef_b (Mar 7, 2010)

If you look at the original question, he was asking if it was okay to put a 36 W bulb in a 40 W fixture. I will admit, I may be wrong about the ceramic comment, but if you reread the article that you posted, it says that most new starters send a current to create the connection, and once the connection is made, the starter stops as the circuit is on. I think that your speaker analogy works for the differential between a 15W and 40 W, as this is a huge difference as well. The initial charge from the starter would be enough to either fry the bulb or the wiring, but as I stated earlier 4 W is not that big of a current differential.


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