400w mh ballast

[msmibew683]

as an electrician i guess i should know this but can a 120volt ballast for a 400w metal halide run two 175 or two 150w or even two 200w mh lamps

 

[msmibew683]

i think i can put two 150w mh lamps in series so the ballast only sees it as one load. as long as the resistive values are either equal to or less than the 400w lamp. any suggestions

 

[PaulErik]

It will not work. Using two lamps will require double the starting/open circuit (OCV) voltage to ignite/start the lamps. A 150/175-watt MH lamp has an OCV requirement almost identical to a 400-watt lamp.

Hope that helps