The number in the table is the capacity. You must reduce it if conditions are not perfect.
Why is this table so important in the real world? Consider a common building mistake: installing a 20-amp breaker with 14 AWG wire (rated for 15 amps). Without the table, an electrician might think, "It's just a few feet; it will be fine." But under a continuous 16-amp load, the 14 AWG wire will exceed 60°C, degrading the insulation over months until a short circuit or fire occurs. The US Fire Administration attributes over 25,000 residential electrical fires annually to improper wiring—most of which trace back to ignoring ampacity ratings. current carrying capacity table
To use these tables effectively:
Current carrying capacity tables, also known as ampacity tables, are essential references for electrical engineers, technicians, and designers. These tables provide the maximum current that an electrical conductor, such as a wire or cable, can safely carry without overheating or causing a fire. The number in the table is the capacity