Circuit Breaker vs wire load.

CB 30AMPERE

30 x 230 = 6900 watts x 80% = 5520Watts

AWG#10

CB 20 AMPERE

20 x 230 = 4600 watts x 80% = 3680Watts

AWG#12

CB 15 AMPERE

15 x 230 = 3450 watts x 80% = 2760Watts

AWG#14

14-gauge are used for light fixtures, lamps, lighting circuits with 15 amps. 12-gauge are used in kitchen, bathroom, outdoor receptacles, and 120-volt air conditioners supporting 20 amps.

A 15-Amp circuit breaker can average between 1800 to 2000 watts. However, it is important to account for the 80 percent NEC rule that states you should load the breaker only to 80 percent of its capacity. This means that it is best to load a 15-amp circuit to 1600 Amp or less.

You can run up to 8 outlets on a 15-Amp circuit, the key is for them to have no more than 1600 Amps total.

When it comes to particular appliances used with 15-Amp circuits, the ones that need a dedicated 15-Amp circuit are:

• Microwaves: the 15-Amp dedicated circuit is enough for smaller countertop conditioners.
• Garbage disposals
• A 120V outlet for timer of a gas stove
• Small-window air conditioners or portable air conditioners

Other appliances that do not need a dedicated 15-Amp circuit but are often used on a shared 15-Amp circuit are:

• Small kitchen appliances include coffee makers, toasters, blenders, and food processors.
• Television sets, desktops, printers, and gaming consoles
• Hair dryers, curling irons, and electric razors. The dryers can actually hold significant power, but they are allowed for 15-Amp circuits because they are only being used for a short time.

Wire Size & Amp Ratings

• Ampacity is the maximum current that a conductor can carry continuously under the conditions of use without exceeding its temperature rating. Current is measured in amperes or “amps.” You must use the correct size wire for the current (load) requirement of the circuit to prevent the wire from overheating.
• The number and type of electrical devices connected to a circuit determine the ampacity requirement of the conductor. Usually, a general-purpose house circuit is designed for 20 amps. Lighting circuits may be designed for only 15 amps
• To calculate the load requirement for a circuit, first add up the wattage of all the electrical devices that will be on the circuit. Then, divide the total wattage by the voltage of the system, typically 120 or 240, and that will give you the required current or amps.

• SIZE OF WIRES FOR OTHER CIRCUIT BREAKERS 

  Here are the sizes of circuit breakers for other common cables in a house:

  • 10 AMP Circuit Breaker - 16 AWG Copper, 14 AWG Aluminum 
  • 15 AMP Circuit Breaker - 14 AWG Copper, 12 AWG Aluminum
  • 20 AMP Circuit Breaker - 12 AWG Copper, 10 AWG Aluminum
  • 25 AMP Circuit Breaker - 10 AWG Copper, 8 AWG Aluminum
  • 30 AMP Circuit Breaker - 10 AWG Copper, 8 AWG Aluminum

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