You should size conductors no less than which percentage of the continuous loads plus what percentage of the non-continuous loads?

The sizing of conductors for electrical installations is based on the National Electrical Code (NEC) guidelines. For continuous loads, the NEC requires conductors to be sized to handle 125% of the continuous load. This is because continuous loads are defined as loads that are expected to run for three hours or more, and increasing the size of the conductors helps to prevent overheating and ensures safety and reliability.

For non-continuous loads, the sizing is based on the actual load without the additional percentage increase, which is set at 100%. Non-continuous loads are those that can be safely assumed to disconnect or shut down before they reach a point where they could cause overheating or failure.

Therefore, when sizing conductors, the correct approach is to take 125% of the continuous loads and add 100% of the non-continuous loads, ensuring that the conductors are adequately rated for the maximum anticipated load. This practice aligns with safety standards and helps in mitigating risks associated with electrical installations.