Suppose we need to size a cable for a residential lighting circuit with the following parameters:
The IEC 60364 standard sets permissible voltage drop limits for different types of electrical installations:
Where:
The standard voltage drop formula for AC circuits is:
Where:
| Installation type | Max voltage drop (lighting) | Max voltage drop (other uses) | |------------------|------------------------------|-------------------------------| | Low voltage installation (public supply) | 3% | 5% | | Low voltage installation (private supply) | 6% | 8% |
Voltage drop is only one part of the cable sizing process. According to the Electrical Installation Guide , you must also consider: TiSofthttps://www.ti-soft.com IEC 60364 requirements - TiSoft iec 60364 cable sizing voltage drop formula
ΔV = (Ib * L * (R + X * tan(φ))) / (1000 * A)
If you need the specific or a spreadsheet calculator , let me know. Suppose we need to size a cable for