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Discussion Starter · #1 ·
How do you determine exactly how many watts a fluorescent fixture uses? For instance, a fixture that has 2 T8-32watt lamps. Is it simply 2 times 32 watts = 64 watts? or is it a combination of the lamps' wattage and the amperage draw of the ballast?

Thank you,
Mike
 

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Amperage draw of the ballast. With fluorescents you can't simply add the lamp wattage. Rated amperage should be labeled on the ballast.
 

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Discussion Starter · #3 · (Edited)
Amperage draw of the ballast. With fluorescents you can't simply add the lamp wattage. Rated amperage should be labeled on the ballast.
Hi Kyle,

Thank you for the quick response.

The following is from a ballast that I have. As you can see it says that the nominal line current is 0.81 A.....but it also lists System Watts as 53. What is the actual power usage of this 2 lamp fixture? .81 A x 120 V = 97.2 Watts or is it 53 system watts?

Lamp Type F32T8, # of Lamps 2 , Line Voltage 120 , System Watts 53 , Nominal line current 0.81 A, System ballast factor 0.83 , Ballast efficacy factor 1.57 , Power factor >0.05 , Crest factor <1.7 , THD % <145 , Min. starting temp 0 °F,
 

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Discussion Starter · #4 ·
Hi Kyle,

Thank you for the quick response.

The following is from a ballast that I have. As you can see it says that the nominal line current is 0.81 A.....but it also lists System Watts as 53. What is the actual power usage of this 2 lamp fixture? .81 A x 120 V = 97.2 Watts or is it 53 system watts?

Lamp Type F32T8, # of Lamps 2 , Line Voltage 120 , System Watts 53 , Nominal line current 0.81 A, System ballast factor 0.83 , Ballast efficacy factor 1.57 , Power factor >0.05 , Crest factor <1.7 , THD % <145 , Min. starting temp 0 °F,


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Lamp Type F32T8, # of Lamps 2 , Line Voltage 120 , System Watts 53 , Nominal line current 0.81 A, System ballast factor 0.83 , Ballast efficacy factor 1.57 , Power factor >0.05 , Crest factor <1.7 , THD % <145 , Min. starting temp 0 °F,
I hope you did not get the typo on the power factor but for the ballast factor that is not too bad at all.

This ballast I can read the THD and that is a strictlly resdentail ballast they are ok to me I rather use the commercal grade ballast due they draw little less current but that not the point at the moment.,

You have to use the ballast amps to get the actual wattage we never read the lamp wattage itself on Flourscent or HIDs at all.

So actual wattage will be about 90 watts due two or three thing can combine can affect everything.

Merci,
Marc
 
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