Wiring and Protection
Bundled Cable Derating Calculator
Bundled Cable Derating is a worksheet for comparing one electrical condition at a time, with the result tied to its inputs.
Run a Bundled Cable Derating check
Use measured values for Bundled Cable Derating when available and rated values only when they describe the same condition.
Where Bundled Cable Derating fits
Use the page when bundled ampacity needs to be checked without rebuilding the equation by hand. The surrounding notes define how far the number should be carried.
Testing single-cable ampacity
Using the sample values, Single-cable ampacity = 35 A; Grouping factor = 0.7, the primary result is 24.50 A.
This Bundled Cable Derating one-input test is a scale check, showing direction and sensitivity without turning the changed case into a recommendation.
If the changed grouping factor comes from a real measurement, keep the original Bundled Cable Derating run so the source of the difference remains clear.
When the scope changes, move to Conductor Temperature Derating and leave this run as the original reference.
Unit handling for Bundled Cable Derating
A clean Bundled Cable Derating result confirms the arithmetic for bundled ampacity; it does not prove the equipment rating or source data is the right one.
Only the entries shown on Bundled Cable Derating feed bundled ampacity. If another correction factor matters, keep it in the notes or make a separate run.
Assumptions not included in bundled ampacity
The arithmetic here is compact, but the use of bundled ampacity still depends on the condition represented by grouping factor. If that condition changes, make a new run instead of editing the old result.
Local code review and manufacturer terminal ratings can be stricter than a simple arithmetic result.
Keeping grouping factor tied to the case
Collect Single-cable ampacity, and Grouping factor from the same operating case before reading bundled ampacity.
- Single-cable ampacity
- Enter single-cable ampacity in A. Default shown: 35 A.
- Grouping factor
- Enter grouping factor. Default shown: 0.7.
Reading bundled ampacity
When bundled ampacity is copied into notes, include the unit and the assumption that controls the result more than display precision does.
Boundaries for bundled ampacity
Spacing and the number of loaded conductors affect the factor.
- Bundling
- Voltage drop
A numerically valid Bundled Cable Derating result can still be wrong if the field condition, connection type, tariff period, or equipment rating does not match.
Help with bundled ampacity
How should multiple scenarios be compared?
For Bundled Cable Derating, keep the baseline unchanged, duplicate the case, and adjust one uncertain value at a time so the reason for the difference stays visible.