What Size Cable for an Electric Shower: Full Guide

gary flood

Gary Flood

Last Updated: 20/04/2024

Choosing the right cable size for your electric shower isn't just a technical decision—it's essential for safety, efficiency, and compliance with building regulations. 

In this article, we'll bridge the gap between your uncertainty and the confidence to make an informed choice. 

You'll learn which cable size fits specific shower models and why choosing the correct gauge is critical for your home's electrical setup. 

We promise to help you understand different cable requirements based on power ratings and installation distances, ensuring you make the best decision for your needs.

Key Takeaways

  • Optimal Cable Size for Electric Showers: The cable size for electric showers primarily depends on the shower's kW rating. Showers up to 7.5 kW typically require a 6mm cable, while showers ranging from 8.5 kW to 9.5 kW need a 10mm cable. For showers 10 kW and above, a 16mm cable is recommended.

  • Cable Size by Shower Power: The correct cable size is crucial for safety and efficiency. A 6mm cable is adequate for showers up to 7.5 kW, a 10mm cable suits showers between 8.5 kW and 9.5 kW, and a 16 mm cable is necessary for high-power showers of 10 kW and higher.

  • Factors Influencing Cable Selection: Aside from power rating, the cable size choice may also be influenced by the length of the cable run, ambient temperature, and installation environment. Ensure these factors are considered to maintain safety and functionality.

  • Installation and Safety: Always consult a qualified electrician to ensure the electric shower and its cabling are installed according to local building regulations and electrical codes to avoid potential hazards.

  • Find out the top rated electric showers in 2024 from Best Electric Showers.

Free PDF: Ultimate Buyer's Guide to Electric Showers

What Do Electric Shower Ratings Tell You?

Electric showers are rated in kilowatts (kW), and this rating directly impacts the size of the cable required to safely and efficiently operate the shower. 

A shower's kilowatt rating indicates its power consumption and output, influencing how quickly and effectively it can heat water. 

For instance, a higher kW rating means the shower can heat more water faster but will require a thicker cable to handle the increased electrical load.

Electric showers typically range from 6kW to 12.5kW. 

The cable size must be chosen accordingly to ensure that it can manage the electrical current without overheating, which could pose safety risks and reduce the efficiency of your shower system. 

Understanding these ratings is crucial for selecting the right equipment and ensuring your bathroom renovation meets safety standards and your personal needs for comfort and convenience.

Matching Cable Sizes to Shower Power: A Simple Guide

When installing an electric shower, selecting the correct cable size is vital for the safety and efficiency of your shower system. 

The cable size depends on the kW rating of the shower, which determines the power the shower will draw. 

Here, we break down the cable size requirements based on different power ratings of electric showers:

Cable Size for Low Power Showers (up to 7.5 kW)

A 6 mm cable is typically sufficient for electric showers with a power rating of up to 7.5 kW. 

This cable size can safely handle the electrical demand of lower power showers, ensuring efficient performance without the risk of overheating.

Cable Size for Medium Power Showers (8.5 kW to 9.5 kW)

For showers that fall within the 8.5 kW to 9.5 kW range, a 10mm cable is required. 

These showers draw more power, necessitating a thicker cable to safely transmit the higher current necessary for heating water more quickly.

Cable Size for High Power Showers (10 kW and above)

Showers with a power rating of 10 kW and higher need even more robust cabling. 

A 16mm cable is recommended for these high-power models to ensure safety and functionality. 

This larger cable size accommodates the increased electrical load without compromising performance or safety.

These guidelines are designed to help you choose the right cable for your shower, balancing safety with performance. 

Always ensure that cable installation conforms to local electrical codes and standards.

Specific Cable Sizes for Popular Electric Shower Models

When planning the installation of an electric shower, it's crucial to match the shower's power requirements with the appropriate cable size to ensure safety and optimal performance. Here, we detail specific cable size recommendations for commonly used electric shower models based on their kilowatt ratings:

Is a 6mm Cable Sufficient for a 9.5 kW Shower?

No, a 6mm cable is insufficient for a 9.5 kW shower. 

For showers rated 9.5 kW, a 10mm cable is necessary to handle the increased electrical current safely. 

Using a 6mm cable for such a high-powered shower can risk overheating and potential electrical hazards.

Can a 10mm Cable be used for an 8.5 kW Shower?

Yes, a 10mm cable is perfectly suitable and often recommended for an 8.5 kW shower. 

This size provides a safe margin to accommodate the shower's power needs, ensuring efficient operation and reducing the risk of cable overheating.

Recommended Cable Size for a 10.5 kW Shower

A 16 mm cable is recommended for a shower with a power rating of 10.5 kW. 

This size will ensure that the cable can handle the high power output safely without any risk of overheating or electrical faults.

The Suitability of 2.5 mm Cable for Electric Showers

A 2.5 mm cable is generally unsuitable for any electric shower due to safety risks. 

Electric showers require a minimum of 6mm cable to ensure adequate electrical load handling and prevent potential hazards.

Following these specific cable size recommendations ensures that your electric shower installation is safe, compliant with electrical regulations, and performs optimally. 

Always consult a qualified electrician to verify that your installation meets all safety standards.

What Else Affects Your Cable Size Choice?

Selecting the correct cable size for an electric shower is about more than matching the shower's kilowatt rating. 

Several other factors play crucial roles in determining the appropriate cable size. 

Understanding these factors can help ensure a safe and efficient installation:

Length of the Cable Run

The distance between your electrical supply (fuse board) and the shower affects the cable size. 

Longer cable runs may require a larger cable size to compensate for voltage drop, ensuring enough power reaches the shower without excessive energy loss.

Ambient Temperature

The environment where the cable is installed impacts its performance. 

Cables in hotter conditions, such as in attics or close to heating units, might require a larger size due to reduced efficiency in higher temperatures.

Installation Environment 

The surroundings where the cable is routed can affect its choice. 

If the cable is run through insulation or bunched with other wires, it may need to be upsized to manage the additional heat generated in such conditions.

Circuit Breaker or Fuse Rating

The rating of the circuit protection (circuit breaker or fuse) also determines the maximum cable size required. 

This ensures the cable can handle the maximum current without tripping the breaker or blowing the fuse.

These factors and the shower’s kW rating ensure a robust system that maintains safety and efficiency. 

Consulting with a professional electrician who can assess these factors in person is highly recommended to determine the most suitable cable for your installation needs.

Safe and Sound: Installing Your Electric Shower Correctly

Proper installation and adherence to safety guidelines are paramount when installing an electric shower. 

This not only ensures optimal performance but also safeguards against potential hazards. 

Here are essential tips and guidelines to follow during the installation of your electric shower:

Consult a Qualified Electrician 

Always use a qualified electrician to install your electric shower. 

This ensures all work complies with local building regulations and electrical safety standards.

Use the Correct Tools and Materials 

Ensure that all materials, especially the electrical cable and circuit protection devices, are suitable for their intended use and meet the required specifications for your shower’s power rating.

Isolate the Electrical Supply

Isolate the electrical supply before beginning installation to avoid accidental shocks. 

This is a critical safety step that should always be noticed.

Check Water Pressure Requirements

Electric showers require specific water pressure. 

To prevent operational issues, verify that your home's water pressure is adequate for your chosen shower model.

Install a Residual Current Device (RCD)

An RCD is a safety device designed to instantly cut off the power in case of a fault, significantly reducing the risk of electric shock. 

It is highly recommended that an RCD be installed for any electric shower installation.

Securely Fix Cabling

Ensure that all cabling is properly fixed and routed away from water sources. 

Use suitable cable clips and conduits to protect and manage the wiring effectively.

Test the Installation

Once the installation is complete, it's crucial to thoroughly test the electric shower and all associated electrical components to ensure everything operates correctly and safely.

Adhering to these installation tips and safety guidelines will ensure your electric shower is a safe and satisfying addition to your home.


© Copyright 2024 Best Electric Shower LTD. All rights reserved. | Company Number: 15606794 | Registered in England and Wales with registered office in Linden Fields, Tunbridge Wells, England, TN2 5QX

Email Support: support@bestelectricshower.co.uk | Customer Support: 02081752283  

Privacy Policy | Cookie Policy | Terms of UseAffiliate Policy

© Copyright 2024 Best Electric Shower LTD All rights reserved | Company Number: 15606794 | Registered in England and Wales with registered office in Linden Fields, Tunbridge Wells, England, TN2 5QX

Email Support: support@bestelectricshower.co.uk | Customer Support: 02081752283  

Privacy Policy | Cookie Policy | Terms of UseAffiliate Policy

© Copyright 2024 Best Electric Shower LTD All rights reserved | Company Number: 15606794 | Registered in England and Wales with registered office in Linden Fields, Tunbridge Wells, England, TN2 5QX

Email Support: support@bestelectricshower.co.uk | Customer Support: 02081752283  

Privacy Policy | Cookie Policy | Terms of UseAffiliate Policy