Get a high qaulity power srtip and dont over load it. You said it could handle 1600 watts, then why did you hook up 1800 watts to it(600x3=1800)? It burned out because you overloaded it. Fires happen and there is more than one grower out there that burent his house and and got fucked by the insurance company because they were growing weed.

you dont have to flower the plants now, when in the vegetative state theyre not so sensitive to the photoperiod.