Dimmer question

[steigs]

I recently installed a dimmer switch on four ceiling cans. Total load is 150w, dimmer is rated for 600. The face plate is off, as the drywall is not up, and I've noticed that the metal housing on the front of the dimmer gets a bit warm... Not hot, but just warm to the touch. Is this just normal resistance generated heat, or should I be concerned about the dimmer?

[nates]

all dimmers get hot, i have one in my living room that has 7 cans on it and it is real hot but nothing to worry about