Use the link on the left to access our cable sizing application. Manage and size all your cables, from low voltage to 33 kV.
Welcome to our cable sizing application.
Our cable sizing application lets you manage and size your cables in a table-based format. It runs as a separate module within our site; to launch it, select 'Cable Engineering' from the main menu.
Use the navigation menu on the left to move between various parts of our site. The menu button will show/hide the navigation menu. To get started, first, create a new project. Then, add a cable to the project and edit the cable to start sizing.
The application is intuitive and can be learned just by using it. The 'App Help' section provides simple guidance and help for using the application. Our sites, 'Knowledge Base' and YouTube channel, provide additional help.
For any issues or problems, you can open a support ticket from our main site.
The application is intuitive to use and self-guiding.
The quickest way to gain familiarity is to use the application and just try out different options. Start by clicking on 'Projects', and add a new project. Go to the projects cables, add a new cable, open this up and change what you need. It really is that simple.
Our application is Evergreen, which means you will always be using the latest version of the app.
When regulations, standards and codes of practice change, we update our application to reflect these. Typically, these changes do not affect the calculations. In a few instances, new requirements may affect the calculation results.
If you need to keep an audit trail, we recommend that periodically you print and file a 'Project Cable Sizing Report'.
We have a collection of written guides and short videos. For most users, the application is straightforward and very little, if any additional help is needed. If you do want more guidance, we publish short videos on our YouTube channel.
Given the application is constantly updated, some of our guides may related to older versions of the app.
If you are still struggling, you can open a support ticket at any time by using the 'Contact Us' button on the main site.
The dashboard is the entrance to the application. From here, you can quickly access cables for your recent projects or check the latest LME metal prices to see if your cables will increase or decrease in price.
The standard reference allows you to drill down to various tables, while equipment data lets you view standard data for common cables and PV modules.
For a video tutorial, please see: Projects - managing projects
Projects are containers to hold your cables. You can add a new project by clicking the '+Project' button. Once a project is added you can edit project details and add cables.
Your projects are listed in a table. You can filter what is displayed by typing search terms and sort the table by clicking on headings. For each project, you can do the actions:
Projects reflect the way you work and are used to organised cable schedules. Once you create a project, you will be able to access its cable schedule and select and work with cables.
To create [add] a new project click the 'Create New Project' button, fill out the project number and name. When you create a project, you are automatically the project owner. As the project owner, you can complete/update project details, add contributors to the project and transfer ownership.
Description: to keep track of your projects, give a meaningful project a number (or other identifier) and description.
Environmental: default values can be set. See Projects - environmental variables.
Branding: You can change the project logo here. The logo will appear on report headings.
Summary/Comments: you can enter comments or summary information about your project here. Comments are printed on various reports. In particular, the 'Project Cable Sizing' report will include comments as the first section. Making it ideal to document scope, assumptions, findings and other relevant project information.
You can update projects by clicking the update button on the projects menu. On the update page you can change the project number and description, set default values or update the logo.
Default values set for temperatures and soil thermal resistivity are used when a new cable is created. Although, they can also be overridden in the cable itself. If you know the actual site conditions, you should enter these, otherwise, by selecting a country from the drop-down list, the default values will be populated with the reference conditions given in the IEC standards.
The logo appears on reports, and you are free to change this and upload your own logo if you wish.
Changing advanced settings may result in your cables being sized incorrectly or not in line with regulations. Only change these settings if you are confident that your decisions will result in compliant cables.
When you create a new cable, the default values of soil thermal resistivity, and ground and air temperatures are used. You can set these default values here. When editing any cable, you can override the default values if required.
Selecting the country your project is based in will populate the default values with suggested values. While you can use the suggested values, it would be better to use the actual values. To use actual values, overwrite the suggested values.
When using environmental variables (temperature and soil thermal resistivity), they are often constant throughout a project. Setting these in the project can make your life easier when entering cables.
You can create and size cables for your projects. To add a new cable, click the '+Cable' button. Once a cable is added, you can then edit and size the cable.
Besides navigating to a project's cables from the projects view, you can also use the projects dropdown box to change projects. Navigating directly to 'Cables', loads cables for the last project you worked on.
Your cables are listed in a table. You can filter what is displayed by typing search terms and sort the table by clicking on headings. You can select cables using the tick boxes. For each cable row, you can do the actions:
You can also use the action buttons to print reports and display different columns in the schedule. When using reports, by default all cables are printed. Only selected cables are printed if one or more cables are selected.
The actions buttons delete, copy and move are enabled when multiple cables are selected and will perform actions on all selected cables.
To keep track of your cable, give a meaningful designation, the start point of the cable, end point of the cable and useful description.
You can select either an a.c or d.c. supply. Depending on the supply type, you must provide the voltage, frequency, phases and earthing system type.
Changing voltage may change the selection of available cables. Setting the frequency to zero will select dc.
Select the type of load your cable will be used with, and provide the anticipated maximum current which will flow in the cable (including the power factor). You can also enter the kW or kVA, and the application will calculate the load current.
For motors, power refers to the motor output. Power factor is fixed unless explicitly changed.
You can select a protective device and trip unit for your cable. If selected, current capacity will be based on the protective device settings. For adjustable protective devices, you can enter a setting lower than the trip unit rating if desired by using the 'Set o/c' checkbox.
If required, you can add an RCD using the 'Add RCD' checkbox and select an appropriate rating from the dropdown.
You can select the cable you would like to use from a selection of generic and manufacturer cables. The selected voltage and system type determine the available cables.
Select the correct value from the dropdown box if you know which CSA you wish to use.
If you wish to calculate the CSA, select any value. Once sufficient data is entered and the sizing method selected, the calculation results will suggest a suitable CSA.
Depending on voltage, selected cables and configuration details, sizing standards may be available. It is possible that no sizing standard covers your cable type, in which case only UDR is available.
Once a sizing standard is selected, appropriate installation methods based on the selected cable are given. Once the installation method is selected, the calculation box will show the cable's sustained current capacity and suggested minimum CSA to comply with the sizing standard.
Our application only uses installation methods defined in the sizing standard. The available methods in the standard may not cover your particular installation requirement. In this event, you can try a different sizing standard.
The available cable CSA is based on manufacturing standards and what manufacturers provide. For a given sizing standard, the CSA which can be sized is based on the values given in the standard. In general, this creates no issues, however in a few cases it may be that the sizing standard does not cover the selected CSA. In this event, the calculation box will display an appropriate message.
As part of the installation, you need to specify the circuit length and number of parallel cables intended to be used for the circuit. The circuit length is the distance from the cable source/start point to the cable destination/end point.
For single-core cables, you need to specify the proposed arrangement and cable spacing if required (edge to edge, 0 = touching).
User defined rating is always available and is the default option. This is used to specify the value of sustained current capacity for the cable, temperature and number of parallel cables at which the rating is calculated.
UDR allows you to keep track of cables where the sustained current capacity is determined by other means, along with cables where the application has calculated the rating. Any entered UDR is used in subsequent impedance, voltage drop and fault rating calculations.
Depending on the selected sizing standard and installation method, you must provide additional derating factor data to enable the calculation.
Note: 'Circuits' is the number of independent cable circuits being run together (include this cable as 1 circuit, plus any additional circuits). Spacing between independent circuits is edge to edge ( 0 = touching).
Enter the maximum allowable voltage drop for your system. This is primarily used to provide a notification if the calculated value exceeds the required maximum.
Provide the expected line-line and line-earth fault ratings (either in kA or impedance), along with the power factor and time before the fault is cleared. Changing a rating value (kA or Ze) will update the other values.
A soil resistivity of 100 Ω.m is typical and can be used in the absence of actual data.
Earth Fault Loop calculations for certain LV cables can be carried out when a protective device is selected. In many cases, the maximum allowable EFL impedance is automatically calculated. Where this is not the case, or should you wish to use a different value, this can be entered.
To reduce EFL impedance, you can choose or add an external CPC or use a spare core if one is available. It is also possible to select to ignore any cable armour in EFL calculations.
You can enter comments or information about your cable here. Comments are printed on various reports. Comments are ideal to document your findings, assumptions, and other relevant cable information.
Creating a new cable or editing an existing cable, brings up the cable edit screen. The cable edit screen is divided into two parts
The edit pages is designed to guide you through the process, with inputting the minimum amount of data. As you go through the form, the selections you make will determine which information is requested (d.c. cables, for example do not require frequency or power factor information). If you get stuck or your calculation is not working, hits are given at the top right (calculation box) on what you need to do.
The calculation box itself is updated after every change and shows current capacity, voltage drop and fault withstand information. The left-hand border is colour coded against some internal checks to indicate if there is a possible issue with the cable. The box overlays the main form and can be hidden (or shown) by clicking the arrow icon.
Note: the application covers all voltages up to and including 33 kV. By changing your cable voltage, the appropriate cables for and options will be presented for you required voltage. The cross-sectional area (CSA) of the cable is selected by the user, however, if a sizing standard is employed, the calculation box will give a suggested size and the user can use this to determine the correct CSA.
The application calculates current capacity to various standards (see the posts sub-topics), positive and zero sequence impedances for the cable by IEC 60909 (see Impedance).
Note: soil resistivity is used in the calculation of zero sequence impedance. If you don't know the actual soil resistivity, leaving it at the default value (100 Ω) is a good option.
Clicking 'Save Changes', saves any changes. You can cancel your editing by clicking the 'Cancel' button.
* the video is recorded using an older version of the application, but is still generally relevant)
A project’s cable schedule is accessed by clicking on the 'Manage Cables' button. The schedule shows the current project at the top, which can be changed by selecting from the drop-down list.
The cable schedule can be filtered by entering search terms in the search box and sorted by clicking on the column headers. Clicking the add (+ ) in the action menu lets you create a new cable, and clicking on a cable field in the grid will allow you to edit the details. Traffic light type symbols show the current status of current capacity, voltage drop and fault withstand calculations for the cable.
By clicking the select boxes to the left, you can select one or more cables. Once selected cables can be deleted by clicking the delete (wastebasket) button.
The action menu and record menu let you work on and use your cables.
Reports are for all cables in the schedule, or by clicking 'print selected only' you can print only cables which have been selected in the schedule.
As you hove over a row the record menu (three vertical dots), is available at the right. From here you can carry out actions specific to an individual cable:
When adding or editing a cable you will be taken to the cable edit screen.
Here we discuss different ways of selecting the correct CSA and go through a live demonstration.
Cables can be moved between projects by using the row action menu or selecting multiple cables and the page menu 'move'.
Entering the correct voltage for your cable is easy, with just a few points to keep in mind.
The meaning of voltage value depends on the type of system under consideration:
For a.c. systems to convert between line-line and line-neutral voltages we can divide (or multiply) by the square root of 3. For example, 300V line-line would be 173.2V line-neutral.
ULN=ULL3
ULL=3ULN
It should be noted that there are also defined IEC and commonly used voltage ranges (line-line/line-neutral), which are rounded: 400/230V, 660/380V, 11000/6350V etc. Within myCableEngineering we use these standard ranges if applicable, otherwise the mathematical conversion
Traditionally cables have been given two ratings (600/1000 V for example) indicating the maximum line-earth (U0) and line-line (U) voltage. However, with the rapid growth of d.c. systems (particularly in the renewable industry), manufacturers are rating their cables accordingly (600/1000 V a.c., 1500 V d.c. for example). Within our cable database, we maintain separate ratings for line-line, line-neutral and d.c for each cable. In the display of cable ratings, we use the following format:
[U0 / U Vac Udc Vdc] - for example [600/1000Vac 1500V dc], 6.35/11kVac [11kVdc]
Cable Selection
Determination and selection of cables are carried out primarily based on voltage and system phase. Typically we will select the next highest rated cables, relative to the system voltage as suitable candidates to use. We further filter the list of cables based on the number of phases (3-phase, 1-phase, etc.) compared to the number of cable cores.
Additionally, we may apply special rules for certain cases:
Calculation of cable impedance is reasonably involved. Other notes give an insight into the individual calculations.
With myCableEngienering, the calculation will typically follow the following procedure
Positive and zero sequence impedance calculated above is in complex form. The real part of the impedance gives the resistance and the imaginary part the reactance.
Currently, we do not calculate capacitive reactance. This will likely be added as the application grows and develops the need for this calculation.
Cable Cores and Phase
Within myCableEngineering, the type of end load (regarding phases) a cable can be used on is dependant on the number of cores.
* there may be additional variations within the application
Note: for armoured cables, the armouring is always considered as part of the earth return path. If the user opts to ignore cable armour, the equations for unscreened cable equations are used. The effect of any return path through the earth itself is considered. If multiple spare cores are available, only one can be used as an earth return path. For any spare core being used as an earth conductor, its impedance is added in parallel with that obtained from the IEC equations.
Reporting is available through the application. Dropdown lists of reports can be found on the Cables page.
Generated reports are exported to pdf and automatically downloaded to the user's computer. You will need a pdf reader or application to view reports.
The billing pages allow you to view and manage your access to our application.
These details will be displayed if you are on a trial (automatically granted on initial registration) or have a fixed end date. You will also be given options to purchase a subscription.
Subscribed users are shown the current subscription, details, and end date. A link to manage an existing subscription is given. Please see Billing - Managing Subscriptions for more information on managing subscriptions.
If you are accessing our application via your company's enterprise licence, the billing page will note this.
Details on subscription pricing can be found on our pricing plans page.
The following infographic show how to purchase, manage or cancel a subscription:
Enterprise licensing includes:
Enterprise users are to control access by adding or removing users to their license.
We have video tutorials dotted about the knowledge base. We will be continuing to add additional tutorials in the future.
If you wish to view all our tutorials in a single location, please visit our YouTube channel.