Does this size the PV DC cable?

No. It estimates voltage drop from entered values only. Cable size, current rating, protection, installation method and product requirements remain separate checks.

Should string current or array current be entered?

Enter current for one string and the number of parallel strings. The calculator multiplies them to produce array current.

Where does conductor resistance come from?

Use a project, manufacturer or competent-person cable data source for the selected conductor and basis. The calculator does not embed cable tables.

What does temperature factor do?

It multiplies the entered conductor resistance to reflect the project resistance basis. Keep its source with the exported record.

Can this approve AS/NZS 5033 compliance?

No. AS/NZS, equipment, DNSP and manufacturer requirements remain external to this arithmetic worksheet.

PV DC cable voltage drop calculator

Iarray = Istring x Nparallel; Rcircuit = 2 x Lm x Rkm x Tfactor / 1000; Vdrop = Iarray x Rcircuit; percent = Vdrop / Vdc x 100

Enter string current from the project source record.
The resistance formula applies outgoing and return conductors.
The temperature factor and voltage-drop target are user-entered source values.
The worksheet does not size or approve PV DC cable.

Formula variables
Variable	Meaning	Unit	Use
Iarray	Array current	A	String current multiplied by entered parallel strings.
Istring	String current	A	Entered current for one PV string.
Nparallel	Parallel string count	strings	Whole number of parallel strings sharing the cable run.
Lm	One-way route length	m	Entered one-way PV DC cable route length.
Rkm	Conductor resistance	ohm/km	Entered single-conductor resistance from the project cable data source.
Tfactor	Temperature factor	factor	Entered multiplier applied to conductor resistance.
Rcircuit	Adjusted circuit resistance	ohm	Outgoing and return conductor resistance for the entered route.
Vdrop	Voltage drop	V	Array current multiplied by adjusted circuit resistance.
Vdc	Nominal DC voltage	V	Entered DC voltage basis used for the percent calculation.
Margin	Target margin	%	Entered target voltage-drop percent minus calculated drop percent.

PV DC cable voltage drop calculator technical guide

Estimate PV DC cable voltage drop from string current, parallel strings, route length and entered conductor data for Australian solar project records.

Use this page when a PV DC cable run needs a traceable voltage-drop record before the result moves into cable selection, protection review, inverter input documentation or a project handoff. The calculator turns entered string current, parallel string count, voltage, route length and conductor resistance into a transparent voltage-drop worksheet.

PV DC Cable Boundary

This calculator is a voltage-drop worksheet. It does not select a cable size, confirm current-carrying capacity, approve an isolator, choose string fuses, set inverter input grouping or decide whether an installation complies with Australian requirements.

Boundary with nearby solar tasks
Task	Use this page?	Why
String current row	Sometimes	Use the PV string current calculator first when module Imp, Isc and parallel strings need a current record.
String voltage	No	Voltage limits from module count and temperature belong to the PV string voltage calculator.
PV DC cable voltage drop	Yes	This page owns the entered current, route length and conductor resistance arithmetic.
Cable sizing	No	Cable sizing needs current rating, derating, installation method, protection and product review.
DNSP or final compliance outcome	No	Network and compliance outcomes sit outside this worksheet.

Data Checklist

PV DC cable source values
Value	Where it normally comes from	Stop if
String current	Module data, string-current worksheet or project record	Current basis is copied from the wrong module or string layout.
Parallel strings	Array layout or inverter input schedule	The run does not actually carry the listed parallel strings.
Nominal DC voltage	String-voltage record or design schedule	Voltage basis is unknown.
Route length	Cable route takeoff or site measurement	The result is close to target and length is only guessed.
Conductor resistance	Cable data source or competent review record	The value belongs to another conductor or temperature basis.
Temperature factor	Project method or cable-data basis	The multiplier source is not recorded.

The useful output is not only the voltage-drop percent. A reviewer needs to see the current source, route length, conductor data and target basis together.

Review Workflow

Confirm the PV DC run reference from the array layout, cable schedule or inverter input schedule.
Enter one-string current and the number of parallel strings carried by the run.
Enter nominal DC voltage from the project voltage basis.
Enter one-way route length, single-conductor resistance and any temperature factor used by the source method.
Compare voltage drop percent with the entered project target.
If the target margin is negative or narrow, review route length, string count, current source and conductor data before using the record.
Carry the exported result forward only with cable data source, current source and reviewer notes attached.

Worked Records

PV DC cable examples
Situation	Inputs	Result	Record use
Two-string residential run	18 A per string, 2 strings, 600 V, 35 m, 1.15 ohm/km, factor 1.1	36 A array current, about 3.19 V drop, 0.53%	Below the entered 1.5% target with source values visible.
Long route review	18 A per string, 2 strings, 600 V, 150 m	About 2.28% voltage drop	Stop for route, cable and project-basis review.
Short single-string row	14.5 A, 1 string, 450 V, 22 m	Low voltage-drop record	Useful as a downstream cable worksheet input.

Stop Points

String current is not tied to a module or array source record.
Parallel string count is unclear.
Conductor resistance is copied from a different cable, temperature or installation basis.
The entered temperature factor has no source.
Voltage drop is above the entered target.
The result is being used as a final cable or protection decision.

String current: 18 A
Parallel strings: 2
Nominal DC voltage: 600 V
One-way route length: 35 m
Conductor resistance: 1.15 ohm/km

Array current36 A
Voltage drop3.19 V
Target margin0.97%

Voltage drop percent0.53%

Maximum route length at the entered target is approximately 98.8 m.

The entered route sits below the voltage-drop target, so the current, route and conductor source can be carried into cable review.

String current is entered from the project PV current record.
Conductor resistance is entered as project data in ohm/km.
The worksheet does not select a cable size or protection device.

String current: 18 A
Parallel strings: 2
Nominal DC voltage: 600 V
One-way route length: 150 m
Conductor resistance: 1.15 ohm/km

Array current36 A
Voltage drop13.66 V
Target margin-0.78%

Voltage drop percent2.28%

Maximum route length at the entered target is approximately 98.8 m.

The voltage-drop percentage is above the entered target, so route length, conductor data and current basis need review.

The same 600 V nominal PV DC context is used.
The target is user-entered, not a universal approval limit.
PV array design, cable rating and isolation remain outside the worksheet.

String current: 14.5 A
Parallel strings: 1
Nominal DC voltage: 450 V
One-way route length: 22 m
Conductor resistance: 1.83 ohm/km

Array current14.5 A
Voltage drop1.23 V
Target margin1.23%

Voltage drop percent0.27%

Maximum route length at the entered target is approximately 121.1 m.

The short route gives a low voltage-drop record, but the conductor and temperature basis should remain attached.

One-way route length is entered in metres.
Temperature factor is entered by the user.
No AS/NZS table values are embedded.