Question about ballast plz help

I have a 400w digital ballast dimmable mh/hps
When I ran my mh on 18/6 had no probs. I've been on my hps for 1 week yesterday I noticed the light would occasionally turn off for like 1 min then back on so I went brought a new globe 55 dollars well it's still doing it not as often but still doing it Iam thinking of buying new ballast even tho this one runs my mh fine could it be my timer or power board or hood ? Also my land lord recently split my power board and they install new wires to the mains box to handle 3 apartments Iam freakin out as Iam 2 weeks into my flower bud coming along nicely

shutting down is a sure sign that something is wrong.... Try to deduce it down to the ballast or timer... a high quality timer is a damn solid investment...

It's weird can stay on for hours the it will turn off it does not even cool down before it restrikes

A "brown out" can drop an arc. A voltage drop could be caused to too small a service and a heavy load kicking in.