The rule of thumb is to only load a breaker up to 80% of its capacity. On a 15-amp service with 14/2 gauge wire one should only load it up to 12 Amps MAX. Since most lights will draw 1 amp per 100 watts a 15-amp breaker can handle one 1K light each. This brings up another point in home growing. That it is always good practice to have the fans and the light that they cool on the same breaker. That way if the breaker is somehow tripped (Murphy's Law) then both the light and its cooling system are down. Instead of the cooling system for the light going down and the light still blazes away because it was on another breaker. Note: above figures are estimated based on 110V supply. can some one please put this in words that i understand? basically i need to know how many watts can i plug into a 110v outlet?....without burning my house down?