DC Cable Sizing Calculator – For PV

Engineering planning aid — verification required. Base current ratings, grouping factors and K constants in this tool originate from the supplied workbook and may include indicative values requiring confirmation against the current licensed Standards, manufacturer data and project conditions. The KEI PV array cable table below is intentionally limited to 6 mm² and 10 mm², matching the PV array cable sizes provided in this public tool. The table is not a substitute for project-specific derating. Do not use the result as a substitute for competent engineering design or statutory compliance review.

1. Project / Circuit

Project / site

Circuit ref

Designer

Date

2. Electrical Inputs

Module Vmp @ STCV

Module Imp @ STCA

Module Voc @ STCV

Module Isc @ STCA

Modules per stringno.

Parallel strings on cableno.

Voc temp coefficient%/°C

Min effective cell temp°C

3. Cable & Installation

Conductor material

Conductor sizemm²

Insulation type

Installation method

Route length (one-way)m

Base rating overrideA

R20 manufacturer overrideΩ/km

Override / manufacturer note

This public PV array calculator intentionally provides only 6 mm² and 10 mm² conductor-size selections. Verify the applicable KEI current rating, installation method, correction factors and project requirements before relying on the result.

4. Correction Factors (CF)

Ambient air temperature°C

Grouping arrangement

No. of circuits in groupno.

Verified grouping CF overridefactor

Extra mutual-heating CFfactor

The workbook's “Spaced ≥ 1D” grouping column is intentionally unpopulated pending verification. This web version therefore requires a verified grouping CF for that arrangement rather than treating a blank as zero.

6. Voltage Drop Inputs

Conductor-temp basis

Design Vd limit%

7. Short-Circuit Inputs

Prospective fault currentkA

Fault clearing times

K constant

K is a verify-against-Table-5.1 input. It depends on conductor material and initial/final temperature conditions.

Calculated Design Summary

String Vmp

—

STC

Cold String Voc

—

max system voltage basis

Design Current

—

Imp × parallel

Overall

—

all applicable checks

Max conductor temp θc

—

INPUT BASIS

Temperature CF

—

CALC

Grouping CF

—

Extra mutual-heating CF

—

INPUT

Base rating Iz0

—

Corrected current capacity Iz

—

Utilisation

—

INFO

Minimum PV rating = 1.25 × Isc × parallel

—

Spare CCC above PV minimum

—

INFO

Voltage Drop & Loss

Calculated operating temperature θop

—

CALC

Temperature used for Vd

—

BASIS

R20

—

DATA

Resistance at design temperature

—

CALC

Voltage drop

—

CALC

Voltage drop % of String Vmp

—

Cable loss

—

INFO

Short-Circuit & Overall Result

Minimum conductor area Smin = I√t / K

—

VERIFY INPUTS

The overall verdict includes the thermal, PV current-rating, voltage-drop and short-circuit checks. This intentionally closes a gap in the supplied workbook's overall-result formula, which did not include its separate PV current-rating PASS/FAIL cell.

Reference / Verification Notes

AS/NZS 3008.1.1:2025: use the current licensed edition to verify installation method, base current rating, grouping/correction factors and K constant. The workbook identifies dedicated DC current-rating and voltage-drop provisions.

AS/NZS 5033:2021: verify PV maximum-current requirements, cable selection, voltage limits and protection for the actual array configuration. The workbook uses 1.25 × Isc × parallel as its PV cable current-rating check.

WA transition: WA Building and Energy advised full compliance with AS/NZS 3008.1.1:2025 from 19 June 2026. Users outside WA must verify the regulatory adoption applicable to their jurisdiction.

KEI H1Z2Z2-K PV Array Cable — Manufacturer Reference
Size	Approx. OD	Single cable in air @ 60°C	Single cable on surface @ 60°C	2 loaded cables touching @ 60°C	Max. R20	Approx. weight
6 mm²	6.5 mm	70 A	67 A	57 A	3.39 Ω/km	87 kg/km
10 mm²	7.4 mm	98 A	93 A	79 A	1.95 Ω/km	132 kg/km

Source: KEI Industries, Solar DC Cable & Wire — BS EN 50618 H1Z2Z2-K product/rating table, accessed 9 September 2026. KEI manufacturer page. Manufacturer table values are reference data only; verify the exact cable construction, installation method, correction factors and project requirements before design use.

Mutual Heating Inputs

Installation environment

Cable overall diameter Demm

Clear spacing between bunchesmm

Number of bunchesno.

Circuits per bunchno.

Within-bunch arrangement

Verified within-bunch CFfactor

Verified inter-bunch CFfactor

Thermal Interaction Result

Independence threshold

—

AIR BASIS

Actual spacing ÷ De

—

CALC

Bunches thermally independent?

—

Within-bunch grouping CF

—

Inter-bunch CF

—

Total grouping CF

—

INFO

For steady DC, this helper treats cable-to-cable interaction as a thermal grouping/spacing effect. It does not add an AC mutual-inductance loss term.

For buried groups, or close/critical spacing, use the applicable AS/NZS 3008 correction factors and project-specific thermal analysis. IEC 60287 may be required for rigorous thermal modelling.

Why the Helper Separates Thermal and Inductive Effects

Steady DC: current is constant, so there is no continuing induced voltage from mutual inductance between neighbouring circuits. Continuous interaction relevant to cable rating is therefore thermal.

AC or significant ripple: time-varying current can create proximity, eddy and sheath/armour losses. Those effects are outside this DC helper and require the appropriate AC/ripple cable-loss method.

Important notice and disclaimer
This calculator is provided by JETS Energy as a general engineering planning aid only. Results are generated from user-entered data, selected assumptions, workbook-derived lookup values and simplified calculation methods, and may not reflect all project, manufacturer, installation, environmental, statutory or site-specific requirements. JETS Energy does not warrant or guarantee that the information, calculations or results are accurate, complete, current or suitable for any particular purpose. Users must independently verify all inputs, assumptions, manufacturer limits, cable data, applicable Standards, regulatory requirements and results before relying on the calculator for design, procurement, installation, construction, certification or operational decisions. To the maximum extent permitted by law, JETS Energy excludes liability for loss, damage, cost or expense arising from use of, or reliance on, this calculator or its results. Nothing in this notice excludes, restricts or modifies any right, guarantee, liability or remedy that cannot lawfully be excluded under the Australian Consumer Law or other applicable law.

© 2026 JETS Energy. All rights reserved. The calculator interface, calculation implementation and associated content must not be copied, reproduced, adapted, reverse engineered, redistributed or used to create a derivative tool without prior written permission from JETS Energy, except to the extent such restriction is prohibited by law. Printed or PDF results may be retained for project records, subject to the disclaimer above.