Electrical load capacity is the total amount of current a wire can handle. The total electrical capacity of the electrical service panel is measured in ampere or amps. When making significant additions to your home, you should calculate the electrical load capacity on anything that runs on electricity in your home.
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The electrical load is measured in wattage or watts, or hours. The electrical load capacity is the total electrical current your household wiring can handle. For example, if you have a refrigerator rated at 600 watts, and a light fixture with two 60-watt bulbs, your wiring circuit's total electrical load capacity cannot exceed 1200 watts or 12 amps.
The national electrical codes are the basis to ensure that wiring is safe and meets safety requirements for a given location. The national electric code recommends that individual branch circuits in a modern residence be at least 40 amps, equivalent to eight standard 15 amp outlets per circuit.