Can I add additional outlets to an existing circuit?
You need to figure the current circuit load in watts to see if it can handle additional use. The National Electric Code is 20 percent less than maximum. This means a 15-amp circuit has a safe capacity of 1,440 watts. A 20-amp circuit limit is 1,920 watts, a 25-amp circuit's limit is 2,400 watts and a 30-amp circuit has a safe limit of 2,880 watts.