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
Fault Calculations - Typical Equipment Parameters

A frequent problem in fault calculations is the obtaining of equipment parameters.  While it is always preferable to use the actual parameters of the equipment...

Fault Calculation - Symmetrical Components

For unbalance conditions the calculation of fault currents is more complex. One method of dealing with this is symmetrical components. Using symmetrical...

Paternoster Lifts

These lifts were first built in 1884 by J. E. Hall and called a paternoster ("Our Father", the first two words of the Lord's Prayer in Latin) due to its...

What does N+1 mean?

The term 'N+1' relates to redundancy and simply means that if you required 'N' items of equipment for something to work, you would have one additional...

8 Motor parts and common faults

Straight forward list of some common motor faults.  If I have missed any other common faults, please take a bit of time to add them in as a comment below...

Understanding LV Circuit Breaker Fault Ratings

I think this post is going to be helpful to several of our readers. While the IEC low voltage circuit breaker Standard [IEC 60947-2, Low voltage switchgear...

Why is electricity so hard to understand?

It's been a busy few months on different projects or busy couple of decades depending on how I look at it. I can say that on the odd (frequent) occasion...

Laplace Transform

Laplace transforms and their inverse are a mathematical technique which allows us to solve differential equations, by primarily using algebraic methods...

Electromechanical Relays

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  While over recent years these have been replaced by microprocessor...

Electric Motors

Collection of links to various places with useful motor information. I’ll try and return to the page every now and again to update it with any motor notes...

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