While there is no specific limit to the number of electrical outlets that can be installed on a single 15 amp breaker, the total load cannot exceed 1,800 watts. This number is calculated by multiplying the standard voltage (120) by the number of amps on the circuit (15).
To determine how many appliances can safely be used on a particular circuit, calculate the individual requirements of each unit. For instance, some standard coffee pots require 800 watts of power while a bathroom blow dryer can use between 300 and 1,200. Refrigerators and microwaves generally draw about 700 watts each. Dedicated circuits should be used for appliances exceeding 1,800 watts.