45a or 50a Shower Switch: Which One is Better for Your Shower?

45a or 50a Shower Switch: Which One is Better for Your Shower?

When it comes to upgrading or installing a new electric shower in your home, ensuring safety and efficiency is paramount.

An integral part of the electric shower installation process is selecting the right switch to manage its power needs.

Two of the most commonly used switches for electric showers are the 45a and 50a switches.

So, which one should you opt for?

Let’s dive into the differences and help you make an informed decision.

What Size Cable For an Electric Shower?
Credit: @UTech UReview

Understanding Electric Showers and Their Power Needs

Electric showers heat cold water instantaneously as it flows through the unit, providing a continuous supply of hot water.

To achieve this, they consume a significant amount of electrical power.

Depending on the kilowatt (kW) rating of the shower, different power needs arise, which would require the use of either a 45a or 50a switch.

The Basics: 45a vs. 50a Switch

45a Switch

  • Typically suited for showers up to 10.8 kW.
  • Provides a slightly lower current than its 50a counterpart.
  • Commonly used in households with moderate power needs for their showers.

50a Switch

  • Ideal for more powerful showers, typically those above 10.8 kW.
  • Offers a higher current, ensuring the shower receives adequate power.
  • Best suited for households looking for a more powerful and continuous water flow.

Why choose a 45a switch over a 50a switch (and vice versa)?

Choosing between a 45a and a 50a switch for an electric shower primarily depends on the shower’s power requirements, installation specifics, and sometimes personal preferences or budgetary constraints.

Here are some reasons for choosing one over the other:

45a Switch:

  1. Shower Power Requirements: If the electric shower has a power rating that aligns more closely with the capacity of a 45a switch, then it’s a practical choice. There’s no need to overspecify if your shower doesn’t demand the higher amperage.
  2. Cost: Generally, a 45a switch might be slightly cheaper than its 50a counterpart. If you’re on a budget and your shower’s specifications align, a 45a could be the economical choice.
  3. Existing Wiring Compatibility: If your home’s electrical setup (like the wire gauge or circuit rating) is already tailored for a 45a switch, it might be easier and more cost-effective to stick with this option.

50a Switch:

  1. Higher Power Showers: For showers with higher kW ratings that demand more current, a 50a switch can safely handle the increased load, ensuring efficient operation and reduced risk of overheating.
  2. Future-Proofing: Even if your current shower doesn’t require a 50a switch, you might be considering an upgrade in the future. Choosing a 50a switch now prepares your system for potential future needs.
  3. Safety Margin: A 50a switch offers a slightly higher safety margin in terms of amperage capacity. If you’re close to the limit of what a 45a can handle, opting for the 50a can be a safer choice, ensuring the switch isn’t constantly operating at its maximum capacity.
  4. Installation Specifics: In some installation scenarios, where cable runs are longer or where voltage drops could be a concern, a 50a switch might provide better performance due to its higher amperage capacity.

Ultimately, while both switches are designed to safely handle the currents associated with electric showers, the choice between them should be based on the specific requirements of the installation, the shower unit’s power rating, and any future plans for upgrades or changes to the system.

When in doubt, it’s always a good idea to consult with a professional electrician.

What happens if you use the wrong Amp switch for a shower?

Both 45a and 50a switches are designed to safely handle the electrical load of the showers they are connected to.

However, using a switch that doesn’t match the power needs of the shower can lead to the following:


If a switch with a lower amperage rating than required is used, it may not be able to handle the current drawn by the shower. This can cause the switch to overheat, which could lead to a risk of fire or melting of the switch components.

Electrical Fires

Overloading a switch continuously can weaken its components and lead to electrical fires, especially if there’s no adequate protection or if the protective devices fail to operate correctly.

Tripped Circuit Breakers

Using a switch that can’t handle the shower’s current might cause circuit breakers to trip frequently. While this is a protective measure, repeated tripping can be annoying and could potentially weaken the breaker over time.

Related: How to fix No Power to Electric Shower?

Reduced Lifespan of Components

Operating electrical components near or beyond their rated capacity can significantly reduce their lifespan. This not only pertains to the switch but can also affect other related components.

Potential Electric Shock

If a switch fails due to being overloaded, there’s a risk of exposing live components. This can increase the risk of electric shock if someone comes into contact with the malfunctioning switch.

Increased Wear and Tear

Operating a switch continuously near its capacity can result in faster wear and tear, leading to more frequent replacements and higher maintenance costs.

Decreased Performance

In some cases, using an under-rated switch can lead to decreased shower performance, as the switch might not provide the necessary current consistently.

Related: Why is My Electric Shower Going Hot and Cold?

Voided Warranty

Using components outside their specified limits might void any warranty on the electrical installation or the shower unit.

For these reasons, it’s crucial to always choose components, including switches, that are appropriately rated for their intended application.

Whenever you have any doubt, it’s always best to consult a professional electrician to ensure the safety and efficiency of any electrical installation.

Related: How to Fix Shower Switch Not Working

Energy Efficiency and Costs

Your choice between 45a and 50a might also influence your energy bill.

A more powerful shower with a 50a switch might consume more electricity.

However, the difference is often minimal unless there’s a significant disparity in usage patterns.

Installation and Compatibility

While both switches are designed to be user-friendly and straightforward for professionals to install, always ensure compatibility with your home’s electrical system.

This means:

  • Using the right cable size to handle the amperage.
  • Ensuring the circuit breaker aligns with the switch’s rating.

Final Thoughts

The decision between a 45a and 50a shower switch largely hinges on the power requirement of your electric shower.

Always prioritize safety and ensure your chosen switch matches the recommended specifications of the shower.

If in doubt, consult with a professional electrician or plumber who can guide you through the selection process and ensure a safe installation.

Remember, the goal is to enjoy a warm, refreshing shower without worrying about technical mishaps.

Choose wisely, and you’ll be on your way to a seamless shower experience!

Frequently Asked Questions

Is a 45 amp switch OK for a shower?

Yes, a 45 amp switch is suitable for many electric showers. However, it’s essential to ensure that the shower’s power rating aligns with the switch’s capacity. Typically, a 45 amp switch can support showers up to around 10.5 kW, but always consult the shower’s specifications and seek advice from a professional electrician.

What isolator switch for 8.5 kW shower?

For an 8.5 kW shower, a 45 amp isolator switch would be appropriate. This rating provides a suitable buffer for the shower’s current demand. It’s always a good practice to ensure the switch is rated at least slightly above the maximum current the shower will draw.

What type of isolator switch for shower?

Electric showers should be fitted with a double-pole isolator switch. This type of switch breaks both the live and neutral lines simultaneously, ensuring complete isolation and increased safety. It should be easily accessible but outside of the bathroom or fitted inside the bathroom, so it’s unreachable from the bath or shower to prevent water contact.

What size switch for 10.5 kW shower?

For a 10.5 kW shower, ideally, a 50 amp isolator switch is recommended. While a 45 amp switch may handle this power under certain conditions, a 50 amp switch gives a better margin of safety and ensures the switch isn’t continuously operating near its maximum capacity.

Can I run a 9.5 kW shower on 40 amp fuse?

While theoretically possible, it’s not advisable. A 9.5 kW shower at 230V will draw around 41.3 amps of current (calculated using the formula Power (P) = Voltage (V) × Current (I)). This means the shower will be operating very close to or slightly over the 40 amp fuse rating. It’s preferable and safer to use a higher-rated fuse, ideally a 45 amp or 50 amp, to account for potential fluctuations and provide a safety margin.