Free Professional Cable Sizing Tool

By EBSP Editorial Team · Jul 17, 2026 · Updated Aug 14, 2026
CableApp shown running on a desktop monitor, laptop, and mobile phone

Correctly sizing electrical cables is a fundamental task in building services engineering. An undersized cable leads to overheating, voltage drops, and potential fire hazards, while an oversized cable results in unnecessary capital expenditure. To address this challenge, Prysmian Group, a world leader in the cable…

A Comprehensive Design Tool for Electrical Engineers

Correctly sizing electrical cables is a fundamental task in building services engineering. An undersized cable leads to overheating, voltage drops, and potential fire hazards, while an oversized cable results in unnecessary capital expenditure. To address this challenge, Prysmian Group, a world leader in the cable industry, offers CableApp—a free, professional tool for calculating the optimal cable cross-section for low and medium voltage installations. This article provides an overview of its features and how it can support your project design.

What is CableApp?

CableApp is a free, professional application designed to help electrical installers, consultants, and engineers select the best cable solution for their projects. Available as both a mobile app and a web application, it provides reliable technical calculations compliant with major regulations, such as Spain’s REBT and RLAT, and is updated to reflect standards like UNE-HD 60364-5-52 (2022).

What sets CableApp apart from similar tools is its focus on both technical and economic/ecological optimization. Beyond calculating the minimum cross-section, it also calculates potential cost savings on energy bills and reductions in annual CO₂ emissions, making it a powerful tool for sustainable design.

Key Features and Capabilities

Accurate Technical Calculations

CableApp calculates cable cross-sections following the criteria of various regulations. A key feature is the 2025 update, which introduced voltage drop calculation at the conductor’s real operating temperature, considering the Joule effect and ambient temperature for more accurate results. Users can also set a maximum conductor size limit, which is useful for adapting to common installation practices.

Sustainability and Economic Analysis

CableApp not only determines the minimum technically required cross-section but can also recommend a larger, more economical size that reduces energy losses over the cable’s lifetime. The tool calculates the total energy savings on the electricity bill and the annual CO₂ emissions reduction, supporting sustainable and cost-effective designs.

User-Friendly Design and Comprehensive Data

The app is designed to be intuitive:

  • Guided Process: Users select the installation type, regulation, and installation method, then input data like current, length, and power factor.
  • Rich Documentation: It includes technical documentation, product datasheets, and illustrative images.
  • Result Management: Users can easily save, print, or share calculation reports in PDF format.
  • Wide Range: It supports a broad range of products, including buried steel wire armoured cables, and covers sections up to 630 mm².

Compliance with Regulations

CableApp is designed to help users comply with relevant standards. For example, it will not offer a cable option that is not legally acceptable based on the installation parameters selected. The 2025 version is fully updated to comply with the new UNE-HD 60364-5-52 (2022) standard.

Who is CableApp For?

CableApp is an invaluable tool for a wide range of professionals in the electrical industry:

  • Electrical Installers: To quickly verify correct cable sizes on site.
  • Consulting Engineers: For detailed and compliant design work.
  • Project Engineers: For optimizing designs and calculating costs and sustainability metrics.
  • Students: As a learning aid to understand cable sizing principles.

Conclusion

CableApp from Prysmian is a powerful, free, and comprehensive tool that goes beyond simple cable sizing. Its integration of technical compliance, economic optimization, and environmental impact analysis makes it a valuable resource for any professional involved in electrical building services design. By using the tool, engineers can ensure safe, efficient, and sustainable cable installations.

Access the Tool

CableApp is available for free on multiple platforms:

  • Web Application: Access it directly at www.cableapp.com.
  • Mobile App: Download it for free from the Apple App Store or Google Play Store.

Disclaimer: This article provides an overview of a third-party tool. While every effort has been made to ensure the information is accurate, always refer to the official Prysmian website and the specific product manuals for the most up-to-date and detailed information. Final design responsibility rests with the licensed professional engineer in charge of the project.

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