HTHOMETALLYTHE PRACTICAL HOME GUIDE

Electrical power/ CALCULATOR

DC cable area for a voltage-drop target

Estimate the copper conductor area needed to keep steady DC voltage drop below a chosen percentage.

Measure from the source to the load; the return conductor is included by the formula.
Use the realistic continuous current at the lowest relevant operating voltage.
Use the voltage basis for the permitted percentage drop.
A project target, not a substitute for an applicable wiring requirement.
Allowed cable voltage drop

0.96 V

Minimum area from voltage drop only

14.58 mm²

Next area in the screening list

16.0 mm²

Drop at the listed area

0.88 V

Drop at the listed area

1.82 %

Cable heat loss at the listed area

70.0 W

Interpretation:Voltage drop alone requires at least 14.58 mm²; the next area in this screening list is 16 mm², with about 1.82% drop and 70 W of cable heat. Verify ampacity, protection and installation rules separately.

Copper resistivity 0.0175 Ω·mm²/m at a reference temperature, equal outgoing and return conductors, steady DC current and a generic metric area list. Temperature, connection resistance, conductor ampacity, insulation, bundling, terminals, fuses, fault current and local rules are excluded. The listed area is a voltage-drop screen, never a complete cable selection.

FROM ESTIMATE TO ACTION

Use the result, not just the number.

01

Verify the inputs

Measure or document each input. If a value is only an estimate, record its source and test a conservative alternative.

02

Keep the calculation traceable

Save the input link or copied result together with the date, units and assumptions. A number without its inputs cannot be checked later.

03

Confirm the decision

Compare the estimate with the related guide, current product data and requirements that apply at your location before buying or building.

Inputs to verify

One-way cable length (m)
Measure from the source to the load; the return conductor is included by the formula.
Steady design current (A)
Use the realistic continuous current at the lowest relevant operating voltage.
System voltage (V)
Use the voltage basis for the permitted percentage drop.
Maximum voltage drop (%)
A project target, not a substitute for an applicable wiring requirement.

Continue your calculation

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