I connected around 10m of christmas light LEDs to a 5V voltage regulator (lm7805). It gets quite hot, put I can still touch it without burning my finger. So in is within its temperature range (120 C max). It's a self regulating voltage regulator so I am not affraid of it burning itself.
But to ensure that my christmas tree wont burn, can I put 2 regulators in parallel to dissipate the heat better?