Electrical

Computes conduit fill from the conductors you enter against the 53, 31 and 40 percent limits, and recommends the smallest trade size that fits. Use it to check whether a conduit is within the fill limit.

Derives a motor's full-load current from its power, voltage, efficiency and power factor, then sizes the branch-circuit conductor, overload and disconnect. Use it for a first-pass motor circuit sizing.

Solves Ohm's law and the AC power triangle from any two known values among voltage, current, resistance and power. Use it for quick electrical calculations across single and three-phase circuits.

Sizes a transformer from the connected load, growth and diversity, and selects the smallest standard kVA rating with its primary and secondary full-load currents. Use it to choose a distribution transformer.

Calculates the voltage drop along a conductor run from its size, length, load current and material, reporting the drop in volts and as a percent against your limit. Use it to check a branch or feeder circuit and find the smallest size that stays within the allowed drop.

Sizes a copper conductor for both voltage drop and ampacity and reports which one governs. Use it to pick the smallest conductor that carries the load and stays within the allowed drop. Aluminium is not covered: the ampacity table this calculator carries does not include aluminium.