after some investigation I found that my Digital greenhouse 400w digi ballast was shutting down because the base of the hps bulb had insufficient contact and had melted the lead. I suppose that it was a good thing that it shut off when it did. I replaced the bulb with a homedepot metal halide and it is back up and running great. Whew!!!!
Check the grounding (green or bare copper wire connects to the ballast housing. Leaving these ungrounded makes too much THD (true harmonic distortion) that rapidly degrades elecricial functioning.
