Conductor size, ampacity, voltage drop, and fault withstand
Voltage Drop Calculator
Estimate voltage drop by current, conductor length, material, cross-section, and phase system.
Open calculatorCable, Wire & Voltage Drop Tools
Engineering calculators for cable sizing, AC and DC voltage drop, derating, AWG conversion, PE conductors, and thermal withstand.
8 calculatorsConductor size, ampacity, voltage drop, and fault withstand
Cable Size Calculator
Find a reference conductor size from load current, sizing factor, conductor material, and installation severity.
Open calculatorConductor size, ampacity, voltage drop, and fault withstand
DC Voltage Drop Calculator
Check DC voltage drop for 12 V, 24 V, 48 V, control, LED, battery, and PV accessory circuits using AWG conductor resistance.
Open calculatorConductor size, ampacity, voltage drop, and fault withstand
AWG Wire Size Calculator
Find the smallest AWG conductor that passes both reference ampacity and voltage-drop checks.
Open calculatorConductor size, ampacity, voltage drop, and fault withstand
mm² to AWG & AWG to mm² Converter
Convert conductor cross-sectional area between metric mm² and American Wire Gauge, with nearest and not-smaller standard-size references.
Open calculatorConductor size, ampacity, voltage drop, and fault withstand
Cable Derating Factor Calculator
Combine ambient-temperature, grouping, installation, and soil factors to estimate corrected cable ampacity.
Open calculatorConductor size, ampacity, voltage drop, and fault withstand
Protective Conductor Size Calculator
Calculate minimum protective-conductor cross-section using the IEC adiabatic equation and a user-selected material k value.
Open calculatorConductor size, ampacity, voltage drop, and fault withstand
Cable Short-Circuit Thermal Withstand Calculator
Check cable short-circuit thermal withstand using conductor area, fault current, duration, and material k value.
Open calculatorCheck conductor performance from load to fault duty
Cable and wire selection must satisfy current-carrying capacity, voltage drop, installation derating, terminal limits, and short-circuit thermal withstand. Conductor material and cross-sectional area alone do not complete the selection.
These tools separate conductor electrical performance from the physical routing and termination questions covered under Cable Management & Installation.
Ampacity, voltage drop, and fault duty are separate checks
A conductor can pass ampacity but fail voltage drop on a long run, or pass normal operation but fail the adiabatic short-circuit check. Each condition should be calculated on the same load, route, material, and protection basis.
AWG and mm² are different nominal systems. A nearest conversion is useful for comparison, but final selection should use an available standard size that is not smaller than the required electrical area.
Applications
Where these calculators fit
Feeder and branch circuits
Estimate conductor size from load, phase, installation method, and allowable voltage drop.
DC and low-voltage systems
Control voltage loss in battery, PV accessory, LED, control, and automotive-style circuits.
Fault withstand
Compare conductor area with fault current and protective-device clearing time.
FAQ
Is cable size determined by current only?
No. Ampacity is only one requirement. Voltage drop, fault withstand, installation method, ambient temperature, grouping, terminals, and mechanical minimums can require a larger conductor.
Can cable outside diameter be converted to mm²?
No. Outside diameter includes insulation, fillers, screens, armor, and sheath. Conductor cross-sectional area must come from the cable construction or datasheet.
Should I choose the nearest AWG equivalent?
Use nearest AWG for reference. For capacity selection, use a standard conductor whose verified area and ampacity meet or exceed the requirement.
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