Ballast amp + light amp = total amps?

smoto

Member
I'm wondering what the TOTAL amps would be when considering my light and ballast combined. The light is a 1000w hps and the ballast claims 9.5 amps at 120v. Calculating the light amps at 120v is about 8.3amps. Does the ballast use an additional 9.5 amps to run the light (17.8amps) or is that 9.5 considered the combined amperes for the light and ballast together? Is the question clear? I've tried searching this topic but no luck. The ideas were never them running together.
 

Mother's Finest

Well-Known Member
If the bulb actually draws 8.3a and the ballast draws exactly 9.5a, then the ballast wastes 1.2a through heat & EMI generation.
 

smoto

Member
I just did a rough calc of the bulb. 1000w/120v=8.33amps. I don't know the true use. So e system usage would be about 9.5 then? I just didn't want to end up over loading the circuit.
 

Mother's Finest

Well-Known Member
If the ballast is rated at 9.5a then it should draw very close to that amount, even if the bulb doesn't use quite that much. Because a ballast starts off at a low output that slowly increases over a short period of time, it is, by design, quite easy on electrical circuits. Any reputable manufacturer that rates their ballast at a maximum draw of 9.5a is specificly saying a 10a breaker & 14awg wiring will cover it. I assume that's what you're driving at.
 

ToastyJoe

Member
No, they are not combined. Its basicaly the bulb size plus a little waste. A 1000W SETUP(Ballast/Bulb) pulls 1000W +/-. About 4.5A-ish/220V and 8.5-9.5A/110
 
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