What is the percentage of current that is allowed to flow through a given breaker with a continuous load on it?

The percentage of current allowed to flow through a circuit breaker with a continuous load is typically set at 80% of the breaker's rated capacity. This guideline ensures that the breaker can handle continuous loads without overheating or tripping. For example, if a breaker is rated for 100 amps, it should not carry more than 80 amps continuously. This rule is part of the National Electrical Code (NEC) in the United States.