You're on the right track, but let's clarify a few things.Here's the breakdown of how conductor ampacity works with continuous loads:1. Continuous Load Defined

A continuous load is a load where the maximum current is expected to continue for 3 hours or more.2.

Initial Calculation (Before Adjustments/Corrections)

The

starting point is that the overcurrent device (circuit breaker or fuse) must be rated to at least 125% of the continuous load. This translates to requiring the conductor ampacity before any adjustments or corrections to be rated at 125% of the continuous load. `Conductor Ampacity (before adjustments) >= 1.25 Continuous Load` `Overcurrent Device Rating >= 1.25 Continuous Load`3. Ampacity Adjustments and Corrections

Next, you need to adjust and correct the conductor ampacity based on factors like:

Ambient Temperature

If the ambient temperature is higher than the temperature rating of the conductor insulation, you need to reduce the ampacity.

Number of Conductors in a Raceway/Cable/Earth

When you have multiple current-carrying conductors bundled together, the heat generated can raise the temperature of the conductors, so you need to reduce the ampacity.

Other factors such as burial depths or insulation types may require further adjustment.The formula for this is:`Adjusted/Corrected Ampacity = Initial Ampacity Adjustment Factor Correction Factor(s)`4. Ensuring Final Ampacity Sufficiency

After applying all the adjustment and correction factors, the adjusted/corrected ampacity of the conductor must still be sufficient to carry 100% of all non-continuous loads plus 125% of all continuous loads.`Adjusted/Corrected Ampacity >= (1.00 Non-Continuous Load) + (1.25 Continuous Load)`

In Summary



You always need to consider the continuous load at 125% when determining the minimum required conductor ampacity before any adjustments or corrections. This ensures the conductor has sufficient capacity from the start. After adjustments and corrections, the final adjusted/corrected ampacity must still meet or exceed 100% of the non-continuous load PLUS 125% of the continuous load. The adjustments and corrections are to account for real-world conditions that affect the conductor's ability to dissipate heat.

Example

Let's say you have a continuous load of 20 amps and a non-continuous load of 5 amps.1.

Minimum Ampacity Before Adjustments

Continuous Load: 20 amps 1.25 = 25 amps Non-Continuous Load: 5 amps 1.00 = 5 amps Total Required Ampacity (Before Adjustments): 25 amps + 5 amps = 30 amps. You need to select a conductor that has an ampacity of at least 30 amps from the appropriate ampacity table (e.g., Table 310.16). Minimum Overcurrent Protection = 25 Amps.2.

Adjustments/Corrections

Let's say you have an ambient temperature that requires a correction factor of 0.82. Your initial conductor ampacity choice was 30 amps. Adjusted Ampacity: 30 amps 0.82 = 24.6 amps.
3.

Verify Adequate Adjusted Ampacity

You MUST now check to see if the adjusted ampacity is adequate: (1.00 Non-Continuous Load) + (1.25 Continuous Load) = (1.00 5 amps) + (1.25 20 amps) = 5 amps + 25 amps = 30 amps.Since your adjusted ampacity (24.6 amps) is less than the required 30 amps, you need to choose a larger conductor (with a higher initial ampacity) so that after the correction factor is applied, the final adjusted ampacity is at least 30 amps.

In essence, you don't get to "skip" the 125% rule just because you're doing adjustments/corrections. The adjustments/corrections only affect how much you need to increase the initial conductor size to account for those real-world conditions. The 125% factor is built into the calculation of the minimum required ampacity before AND after adjustments/corrections. Flag for review