Disclaimer
What these tools do, and what they explicitly do not do.
These are calculation tools
The calculators on this site compute what the stated formulas produce from the values you enter, using the reference data cited on the methodology page. They are intended for engineering estimation and for education.
They do not determine compliance
A voltage drop calculation is arithmetic and carries no code authority. An ampacity figure shown here is a base table value before any correction or adjustment factor, before terminal temperature limitations, and before the overcurrent-protection rules that govern a real installation. Neither is a determination that anything complies with any electrical code.
They model an ideal conductor
The calculations account for the conductors and nothing else. They do not include resistance at terminations, splices, breakers, switches or devices; they do not model harmonics, unbalanced three-phase loading, motor inrush, source impedance, or the specific conditions of an installation. A measured voltage drop will normally exceed a calculated one.
Reference data may not match your edition
Values are drawn from published sources current at the time of writing and cited individually. Electrical codes and standards are revised, and the edition adopted in your jurisdiction may differ from the one referenced. Confirm against the tables in the edition that applies to you.
Use qualified judgement
For work that will be built, follow the electrical code in force where the work is done, the equipment manufacturer’s data, and the direction of a qualified person. Electrical work carries risk of injury, fire and death; nothing on this site replaces the training and authorisation required to do it safely.
No warranty
This site is provided as is, without warranty of any kind. The operator accepts no liability for any loss or damage arising from use of, or reliance on, anything published here. If you believe a value is wrong, please say so. Accuracy is the point of the site.