When should I use this instead of the normal voltage drop calculator?

Use this when the route has different segment lengths or cable data values that need to be summed separately.

Does this choose cable sizes for each segment?

No. It uses mV/A/m values entered by the user and reports the summed voltage drop.

Can segment two or three be blank?

Yes. Leave optional segments blank or 0 when the route has fewer than three segments.

Why show the largest segment?

The largest voltage-drop contributor is often the first part of the route to review when the total is high.

Does this prove compliance?

No. Standards, cable data, project limits and competent review remain outside the calculator.

Segmented route voltage drop calculator

Vdrop_total = sum(mVAm_i x I x L_i / 1000); Vdrop_% = Vdrop_total / V x 100; margin_% = target_% - Vdrop_%

Segment mV/A/m values are entered by the user.
Optional blank segments are treated as unused.
The page sums segment drops only.
It does not reproduce controlled cable tables or decide compliance.

Formula variables
Variable	Meaning	Unit	Use
mVAm_i	Segment cable data	mV/A/m	Entered voltage-drop data for each segment.
I	Load current	A	Current flowing through the route.
L_i	Segment length	m	Entered one-way length for each segment.
Vdrop_total	Total voltage drop	V	Sum of each segment voltage drop.
Vdrop_%	Voltage drop percent	%	Total drop divided by the entered voltage basis.
target_%	Entered target	%	User-entered project comparison target.
margin_%	Target margin	%	Entered target minus calculated voltage-drop percent.

Segmented route voltage drop calculator technical guide

Estimate Australian voltage drop across a segmented cable route from entered segment lengths, cable data and load current.

Use this calculator when a cable run has distinct route segments with different lengths or cable data values. It keeps each segment visible, then adds the voltage drop contributions into one project record.

Field use cases

Segmented voltage-drop use cases
Work setting	Real question	Useful action from this page
Board-to-board route	Which segment contributes most of the total drop?	Enter each length and mV/A/m value separately.
Mixed cable data	How much does a cable-size change affect the route total?	Keep each segment source value visible.
Long upstream section	Is the long segment dominating the result?	Review the largest segment output first.
Design review record	Is the total inside the entered project target?	Compare total percent drop with the entered target.
Route revision	Which changed segment should be updated?	Adjust only the affected segment inputs.

The page is intentionally a segment summation worksheet. For one uniform run, the standard voltage-drop calculator is cleaner.

Data checklist

Segment input checks
Value	Where it normally comes from	Stop if
Segment length	Drawing, cable schedule or measured route	The entered length is not one-way route length.
Segment mV/A/m	Cable data source or project record	The value belongs to another cable or installation basis.
Load current	Load calculation or design record	Current differs between segments and the route model has not been reviewed.
Voltage basis	Supply or equipment basis	Percent drop is being compared to the wrong voltage.
Target percent	Project requirement or design assumption	The target is not documented.

If segment data is uncertain, keep the result as a draft calculation record.

Method comparison matrix

Segmented method boundary
Method element	What this calculator does	What remains outside
Segment drop	Calculates mV/A/m x current x length / 1000.	Selecting the mV/A/m value.
Route total	Adds each populated segment drop.	Whether the route split is the right design model.
Largest segment	Identifies the highest segment contribution.	Engineering decision on which segment to change.
Target margin	Compares total percent with user-entered target.	Final standards or project approval.

The result is most useful when the worksheet shows enough detail for another reviewer to repeat the segment total.

Worked records

Segmented route examples
Situation	Inputs	Result	Record use
Mixed route	63 A, 400 V, segments 25 m, 18 m and 12 m	5.647 V total, about 1.41%	Segment one is the largest contributor.
Long first segment	70 A with a 58 m first segment	Long segment review applies	Review route allocation and cable data.
Target exceeded	Three longer segments with a 1% target	Outside the entered target	Review segment data and route design.

The examples show why a segmented route should not be hidden inside one average cable-data value.

Stop points

Segment lengths are not on the same one-way route basis.
mV/A/m values are copied from unrelated cable data.
The route has changing load current between segments and needs a different model.
The total is above the entered target and no segment review has been done.
The result is being used as final compliance evidence without project review.

A useful export record includes the route reference, current, voltage, target, each segment length, each mV/A/m value, total voltage drop and largest segment.

Route reference: SEG-ROUTE-1
Load current: 63 A
Voltage: 400 V
Segments: 25 m, 18 m, 12 m

Segment drops3.31 V, 1.64 V, 0.7 V by entered segment.
Total drop5.65 V across the entered route.
Percent drop1.41% against the entered voltage basis.

Segmented voltage drop1.41%

Target margin is 0.59%.

The segmented route is inside the entered target, with segment one contributing the largest drop.

Each mV/A/m value is entered from the project cable data source.
The route is summed as three one-way segments.
This page does not replace the single-run voltage-drop calculator.

Route reference: LONG-SEGMENT-1
Load current: 70 A
Voltage: 400 V
Segments: 58 m, 16 m, 0 m

Segment drops8.93 V, 1.34 V, 0 V by entered segment.
Total drop10.28 V across the entered route.
Percent drop2.57% against the entered voltage basis.

Segmented voltage drop2.57%

Target margin is -0.57%.

The route is close enough to the entered target that the long first segment should be reviewed.

Blank segment three is treated as 0 m.
The entered target is a project value.
Cable-size selection remains outside this worksheet.

Route reference: SEG-REVIEW-1
Load current: 63 A
Voltage: 400 V
Segments: 50 m, 30 m, 20 m

Segment drops6.62 V, 2.74 V, 1.16 V by entered segment.
Total drop10.51 V across the entered route.
Percent drop2.63% against the entered voltage basis.

Segmented voltage drop2.63%

Target margin is -1.63%.

The sum is above the entered target, so cable data, route splits and target basis need review.

All segment data is entered by the user.
The largest segment is highlighted for review.
The result is not a final compliance decision.