A panel that feels warm to the touch is not normal. Warmth at the panel almost always means a connection somewhere inside is loose or corroded, and a loose connection under load generates heat.
What causes a warm panel
Every termination inside a panel is a mechanical joint. Over years of thermal cycling, aluminium conductors in particular can relax slightly in their lugs. The joint gets marginally looser, resistance rises, and resistance under current produces heat.
What to do right now
If the panel cover is warm, stop using the heaviest circuits in the house and call a licensed electrician the same day. Do not open the cover yourself.
A thermal inspection and a torque check on every termination usually finds it in under an hour. Left alone, a warm connection is one of the more common causes of residential electrical fires.
