How to install an electric shower?

Installing an electric shower is relatively simple, after all there are only three cables to connect, isn’t it? Although the installation is apparently simple, make no mistake, because there are other fundamental factors that we should be concerned with when installing an electric shower, so we should ask some important questions, such as which shower circuit breaker? Shower 127V or shower 220V? Which shower connector? Which cable to use for the shower? What to do when there is no grounding?

Answering these and other questions is essential for proper and safe installation, so there are no problems with the installation and put lives at risk. Thinking about the risks of installing or replacing a shower, we will clarify these and other doubts about the correct way to install a shower, in addition to showing step by step how to install a shower.

Shower 127V or 220V?

Before installing any electric shower it is necessary to know its supply voltage, whether it is 127V or 220V. This information basically depends on two factors, which is the availability of the concessionaire in your region and the installation of your residence. Installing a shower that is not compatible with the installation will cause the shower to malfunction or burn it out, so use a multimeter to identify what the voltage is.

It is important to note that it is very common for some people to think that 220V saves electricity, when in fact it does not interfere with anything in relation to the consumption of electricity.

How to install an electric shower?

Which shower breaker?

Circuit breakers are protection devices designed to withstand a certain electrical current, in the event of a short circuit or an overload, the circuit breaker will interrupt the circuit. Therefore, if the circuit breaker is badly dimensioned, many problems can arise, the most common of which is the trip circuit breaker.

We must choose a circuit breaker with the correct curve, and its current must be in accordance with the rated current of the electric shower, the most common causes of problems with the circuit breaker is to switch to a shower of greater power and to resize the shower and the electric cables of this circuit.

To make it clearer in relation to the dimensioning of the shower circuit breaker, we will use as an example a shower that dissipates a maximum power of 5500W, powered by a single-phase 127V voltage.

It is very simple to obtain the value of the circuit breaker, for this it is enough to divide the maximum power of the shower by its supply voltage, thus the maximum current that will be required by this shower is approximately 43A. In this situation, we must choose a circuit breaker of at least 43A, never with lower or very high values. Therefore, the closest selection value for a circuit breaker is 50A.

Which cable to use for a shower?

Just like an incorrectly sized circuit breaker, a badly dimensioned conductor results in several problems, such as the melting of the conductors among other even more serious events, when combined with the improper dimensioning of the circuit breaker.

For the proper sizing of cables for the shower, we must take into account the distance between the circuit distribution board (QDC) and the point where the shower will be installed, in addition to checking the current required by the shower.

Using the previous example, manufacturers require a cable with a section of at least 10mm² for a voltage of 127V, remembering that the cable section can vary according to the voltage, power and distance between the shower and the circuit breaker.

How to install shower?

Before installing the shower, we must turn off the shower circuit breaker or general circuit breaker, make sure the circuit is de-energized, using a test switch and ensure that no one will accidentally rewire the circuit, for this we recommend the use of a padlock.

Which connector to use?

Connect the shower cables to the installation cables using wago connectors or porcelain connectors, tighten the connector screws securely. We do not recommend making amendments , as it causes great heating at this point, causing greater damage to the installation.

Shower installation

The electrical installation of the shower is very simple, first we strip the installation and shower cables with the help of stripping pliers. Then we connect the power cables, without restriction in relation to the phase and neutral cables, the only restriction being in relation to the connection of the grounding cable, which is the green or green and yellow cable of the shower. See the wiring diagram in the image below.

Shower installation scheme.

Where to connect the ground cable?

Where to connect the shower ground cable is what causes the most doubts at the time of installation. For installations that have a grounding cable, the answer is obvious and simple, as it is enough to connect the shower grounding cable to the installation grounding cable.

When the electrical installation does not have a grounding cable, it is very common for people to make mistakes, as they end up connecting the shower grounding cable together with the installation’s neutral cable. In this situation the best option is not to use the grounding cable, we must not connect it to the neutral cable of the installation, that is, just leave the grounding cable isolated, out of reach and hire a qualified professional to do the installation grounding.


Before turnwing the shower on, put it in the off position, then open the entire water valve and let the water drain for a short time, so that the shower does not burn, then just change the position of the key to the your preference, but do this with the shower off.

The video below shows step by step how to install an electric shower correctly, clarifying the main doubts when installing the shower.