Tools

Cable Sizing Application

Click here to register to use our cable sizing application

What Changed

So that we can focus all our efforts on our new application, we have retired our myElectrical.com cable sizing calculator. We recommend you now use our main cable sizing application over at myCableEngineering.com.

myCableEngineering.com

Cable Sizing Software - select, size and manage your power cables using myCableEngineering. All your cables, for all your projects.
  • LV and MV cables up to 33 kV with current capacity in accordance with BS 7671, ERA 69-30 and IEC 60502.
  • Positive and zero sequence impedance to IEC 60609. Voltage drop in accordance with CENELEC CLC/TR 50480.
  • Project management and team collaboration, with clear easy to read calculations and reports.

Our software is the only cloud-based solution and has been built from the ground up to be fully responsive - meaning you can access your cables from anywhere and on any device, desktop, tablet or smartphone.

Duct Size Calculator


Tip: registered users can save calculations.

Typical Cable Diameters

Following outside diameters are for reference only and will vary depending on cable manufacturer. 

600/1000V XLPE Armoured

Overall Diameter (mm)
mm2 1core  2 core  3 core  4 core 
1.5    12.3  12.8  13.5
2.5    13.6  14.1  15.0
4    14.7  15.3  16.4
6    16.9  16.6  18.7
10    18.0  19.5  21.1
16     20.0  21.2  22.9
25    24.1  26.7  28.9
35    27.9  29.6  32.1
50*   17.5  25.8  28.5  32.0
70   20.2  29.0  32.2  37.7
95   22.3  33.1  37.0  41.7
120   24.2  36.1  40.0  47.7
150   27.4  39.3  45.5  51.4
185  30.0  44.7  49.8  56.6
 240  32.8  49.0  55.1  63.0
300  35.6  53.5  60.2  68.8
400  40.4  59.0  66.6  78.1
500  44.2      
630  48.8      
800  55.4      
1000  60.6      

 * - change in class of conductor

Calculation

1. Required fill factor k (in decimal)
2. Cable diameter d, giving a cable area, a:

a= π 4 d 2
3. Cable total area Ca = sum of area for all cables
4. Minimum duct diameter D:

D= 4 C a πk
Photovoltaic (PV) - Utility Power Grid Interface

Photovoltaic (PV) systems are typically more efficient when connected in parallel with a main power gird. During periods when the PV system generates energy...

Arc Flash Calculations

Working in the vicinity of electrical equipment poses an hazard. In addition to electric shock hazard, fault currents passing through air causes Arc Flash...

Understanding Motor Duty Rating

One of the comments on my Motor Starting Series was asking for something on duty cycles. Here it is. As a purchaser of a motor, you have responsibility...

Cost Performance and Time

Often us engineers get so bogged down in equations, using software, producing drawings and writing specifications that this becomes the sole focus.   ...

Electromagnetic Fields - Exposure Limits

Exposure to time varying magnetic fields, from power frequencies to the gigahertz range can have harmful consequences.  A lot of research has been conducted...

Electromechanical Relays

Electromechanical relays have been the traditional backbone of electrical protection systems.  While over recent years these have been replaced by microprocessor...

Earth Electrode Resistance

Earthing of electrical systems is essential for the correct functioning and the protecting of life and equipment in the event of faults.  The earth electrode...

Low Voltage Fault Tables

The following tables provide quick order of magnitude fault levels for a a range of typical low voltage situations.

Understanding Circuit Breaker Markings

IEC 60947 is the circuit breaker standard and covers the marking of breakers in detail. Any manufacturer following this standard should comply with the...

How a Digital Substation Works

Traditionally substations have used circuit breakers, current transformers (CT), voltage transformers (VT) and protection relays all wired together using...

Footer
(click here to extend)
Copyright (c) 2026 myElectrical