The safety of a showerhead, he points out, begins by first understanding the basics of how it works.

The components

An instant showerhead has three main components; the electrical wiring, the on/off and water temperature control switches, and two heating elements.

The first wire is the live wire which carries the electric current from the switch to the showerhead. Then there is the neutral wire which takes the current back to the switch to complete the circuit. The third wire, which is very important, is the earth wire. This is the only wire that comes into direct contact with the water inside the showerhead bowl, and its main purpose is to safely dispense electrical currents that may be in the water to prevent electrocution.

The earth connection is usually connected for the whole house or apartment building, ending in an earth rod, usually planted in the ground. It is therefore essential that wiring is done correctly, since a fault in a showerhead will affect every appliance in the entire building that has a water connection.

The risk of electrocution presents in two ways. First, if the earth is not properly installed and is therefore malfunctioning, it means there will be no connection to dispense the extra electrical current in the shower water that leaks through as the circuit from the main switch to the showerhead and back, is completed. This will not only cause electrocution in the shower, but elsewhere one touches water while standing on the ground, especially barefoot. In this case, the risk of death is not very high, however, you might experience some symptoms. For instance, your hands might feel numb if you are washing dishes in the kitchen. The second and more critical risk of electrocution happens if the live wire is directly touching the earth wire. Although this is rare, it can occur if someone without proper knowledge wires a house. As the earth is directly in contact with the water in the showerhead bowl, then the risk of death by electrocution is very high, since the electricity currents flow directly into the water, without any mechanism to dispense them.

Showerheads can be classified based on size: small, medium and large, or by water type; soft water showers or hard water showers. The size one chooses should be dictated by water pressure. If the water has a lot of pressure, then a larger showerhead will be better as it has the capability to heat more water and at a faster rate. If the pressure is low, then a smaller showerhead is recommended.

Knowing the water type where you live is also important, since using a soft water heater with hard water can lead to damage of the appliance. The salt in the water will be deposited on the heating element, and within a short time, corrode it, making it useless.

The heating process

When you switch on the shower switch, usually outside the bathroom door, you allow the current to flow to the showerhead, however, a properly working quality shower should not start heating until you turn on the water.

As water fills the bowl inside the showerhead, a diaphragm inside, which has two terminals, rises and connects with the live and neutral wires supplying the electric current. As the heating elements start heating, so does the water. When you turn off the water, the diaphragm should automatically lower and disconnect, stopping the heating process, and this is where one of the first dangers of a showerhead comes in.

With a poor quality showerhead, the diaphragm might malfunction. That means the heating elements will continue heating up without any water flowing through, leading to overheating and damaging of the shower. As the showerhead heats and melts, so will the electrical wires inside. If the neutral and live wire come into contact, there will be an electrical short circuit which can lead to a fire breaking out. This can, however, be mitigated by ensuring the shower connection has a manual switch outside the bathroom, as is in most cases.

If a showerhead has three heating modes; low, medium and high, then it means the two heating elements are different. While in low setting, the smaller element heats the water, in medium setting, the larger element heats the water, and in high, they both heat simultaneously. This should be adjusted based on water pressure, to avoid getting burns.

On the sparks that you sometimes see when you turn on the shower, that is to be expected. This happens as the showerhead terminals are connecting to the electrical wires and happens in all showers, even where you cannot see the sparks, depending on quality and make. These sparks should therefore not be confused with a malfunctioning shower, for instance, one that does not turn off after stopping the water flow, which might show a bright light as the elements overheat.

The connection requirements

A shower should be connected directly from the consumer unit (the main switch) with a 4mm cable, however, to cut on costs, most people use a 2.5 mm cable, which is dangerous because this cable is too small to handle the power flow requirements. The wire might end up expanding and heating over time, destroying the plastic coat on the wire and becoming a fire hazard due to short circuiting as the live and neutral wires come into contact.

When it comes to the switch, some people want to forgo it, which can be dangerous. In case a house does not have a switch and one fails to tightly close the water, then the water will keep filling the bowl, and the shower will eventually turn itself on. The shower switch should be 25 amperes for a small one and 45 amperes for a big showerhead. There should also be a 32 ampere circuit breaker in the consumer unit, which acts as protection against power surges.

In a nutshell, proper earth connection is critical. Since this wire is constantly dipped in water, and all the water in a house or apartment is connected, it means that if there is a problem in one house, then you might get shocked while opening a tap in the kitchen for instance. The shock might not be life-threatening, but since the power trickle is continuous, you might experience excessive numbing in the hands after, say, washing utensils.

The bottom line

Instant showerheads are relatively safe, and their benefits outweigh their risks, however, your safety will be determined by the quality of equipment used, and observing safety standards, for instance, using the proper cable sizes.

Different connections require different wire sizes, and one should not use smaller or substandard size cables and equipment just to save on costs, as this endangers users. Also, consulting a qualified electrician will ensure that you get good quality products.

Having one electrician do all the wiring in a house or building is also important, as it reduces the risk of wrong connections, and makes repairs easier as the electrician understands how the wiring was done and where the problem could be.