Ballast heat- when to be worried?

My ballast (only running about 4 hours a day at the moment) heats up after it's been turned on for about 2 hours. I would definitely describe it as hot rather than warm but it's still OK to touch it. How much does your ballast heat up?

Mine gets rather warm too. It's normal. Are you concerned with your ballast heating up your grow space? I have mine outside my room so it's a non-issue.

Mines outside as well so the heat is a non-issue. I'm concerned about a potential fire hazard...have been since I noticed this inside the bulb. It's a brownish spot.

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Good to know the ballast heat is normal though, thx