ballast question

hi people just a question about lighting ive got my floros in my veg box and ive aqiured a 250w ballast so i wired a 75w sodium bulb to it instead of a 250w because i just wanted to give my little seedlings a little boost until i put them under my 400w to veg (cant do this until i chop my other plant down) so as i was saying this 75w sodium it comes on and it goes bright as hell then it flickers abit and goese even brighter it does this for about 10 mins then it cuts out i thought it had blown my bulb but i tested it this morn and it still worked i just turned it off straight away so can anyone tell me if a 75w can be wired to a 250w ballast?? (without any risk of fire ect)

thanks clubber :)

your just over volting it for the wattage. be careful

so is it ok to wire the bulb to the ballast or do i need to get a lower watt ballast??

The running voltage is not the same. Some run on 277v out of the transformer and some run on 208v out of the transformer. You must match the bulb to the transformer output voltage.

how can i find this out??