When manufacturer device data matters
How to recognise protection questions that need manufacturer data, time-current curves or engineering review instead of a public calculator result.
Boundary purpose
Public calculators are useful for transparent relationships: voltage divided by impedance, entered fault current, entered clearing time and worksheet comparisons. They are not substitutes for protective-device data.
Manufacturer data matters whenever the answer depends on how a real device behaves under a specific condition.
Hand-off workflow
- Use public calculators to prepare transparent relationship values.
- Identify whether the next decision depends on a real protective device.
- Gather manufacturer data, device ratings, curves or instructions.
- Record the product source and version.
- Stop for engineering review when coordination, selectivity or let-through behaviour controls the answer.
Manufacturer-data triggers
| Trigger | Why public formulas are not enough | Hand-off |
|---|---|---|
| Breaking capacity | Product rating and installation context matter | Manufacturer and project review |
| Time-current behaviour | Curves differ by product | Current device data |
| Let-through energy | Device-specific performance matters | Manufacturer data |
| Selectivity | Upstream and downstream devices interact | Engineering study |
| RCD/RCBO details | Device type and test requirements differ | Product instructions and test record |
Boundaries
- Do not use public calculators as manufacturer data.
- Do not copy time-current curves into guide copy.
- Do not infer selectivity from a single current value.
- Do not hide product version or rating source.