Modern household appliances require not only proper connection to the water supply, but also reliable protection from electric shock. Grounding the refrigerator is a critically important procedure, ignoring which can lead to serious consequences for the health of residents and the safety of expensive equipment. In old houses, there is often no third contact in the socket, which creates the illusion of safety, although in fact the body of the device may be at a dangerous potential.
If a breakdown of the insulation of the compressor or heating element occurs, electric current flows to the metal casing. If you touch such a refrigerator while standing on a wet floor or simply holding a faucet in your hand, an electric shock will be inevitable. That is why ground loop discharges this current into the ground, causing the circuit breaker or RCD to trip before anyone gets hurt.
In this article we will look in detail at why you can’t just stick a wire into a battery, how to properly organize current drainage in a private house and apartment, and also what mistakes inexperienced craftsmen make. You will learn what tools you will need for the job and how to check the effectiveness of the created protection using a multimeter.
Why grounding is necessary for a refrigerator
The main reason for the need for grounding lies in the design of the refrigeration unit itself. Powerful compressor electric motors, heating elements of the No Frost system and electronic control boards operate inside the housing. Over time, the insulation of the wires dries out from vibrations and temperature changes, which can lead to current leakage into the housing. Without grounding, this current will not go anywhere, waiting for contact with a person.
In addition, modern models are full of sensitive electronics, which are extremely susceptible to static electricity and power surges in the network. Grounding conductor helps stabilize the electrical potential, reducing the risk of failure of expensive control modules. This is especially true for premium models with digital displays and Wi-Fi modules.
⚠️ Attention: Operating a refrigerator without grounding in rooms with high humidity (kitchens, bathrooms in studios) increases the risk of death due to insulation breakdown several times.
It is also worth considering that many manufacturers directly indicate in the passport Indesit, Bosch or LG the requirement for mandatory grounding to maintain the warranty. In the event of a breakdown, the service center may request a report of checking the electrical network, and the absence of “earth” will become a legal basis for refusing free repairs.
Assessing the condition of the electrical wiring in the house
Before you grab the tools, you need to understand what kind of power supply system you are dealing with. In modern new buildings, a system is used TN-Swhere the grounding conductor comes separately from the transformer substation and is present in each outlet. In this case, the task comes down to only checking the integrity of the contact.
In Soviet-built houses and "Khrushchev" buildings, the most common system is TN-Cwhere the zero working and zero protective conductors are combined. In such apartments there are only two wires in the sockets: phase and neutral. There is no physical grounding here, and its creation requires separate measures that extend beyond the boundaries of one apartment.
There is also a transition system TN-C-Swhich is found in houses after major renovations. Here there is a grounding connection in the panel, but so far only two wires can come into the apartment. To organize protection, you need to find out from the management company whether the home network is ready to separate the PEN conductor.
How to distinguish the wires in the panel?
The phase wire usually has brown, red or white insulation. The neutral wire is always blue. The grounding conductor is marked yellow-green. If there are only two cores in the cable, there is no grounding.
Methods of organizing grounding in a private house
Owners of private houses are luckier, since they can create an individual one grounding circuit right on the site. This is the most reliable way to ensure the safety of all household appliances. The process involves digging metal pins into the ground and connecting them to the input shield.
To organize the circuit, steel corners or copper pins are used, which are driven into the ground to a depth below freezing of the soil (usually 2-3 meters). They are connected to each other by a steel strip, forming a triangle or line. From this structure, a grounding bus goes to the house, which is connected to PE bus in the electrical panel.
☑️ Checklist for installing the circuit
Resistance to current spreading should be minimal. For household networks it should not exceed 30 Ohms, and for gas boilers and sensitive equipment the requirements may be even stricter. After installation, be sure to call specialists to take measurements.
Features of grounding in an apartment building
In apartment buildings the situation is more complicated, since the land belongs to all owners, and digging trenches in the yard is prohibited. If the house has not undergone a major overhaul with the replacement of risers, residents of the upper floors can only hope for the management company to modernize the network. However, there are technical solutions for such cases.
One of the options is organization potential equalization systems. All metal parts in the bathroom and kitchen (pipes, bathtub, refrigerator frame) are connected to the building's main ground bus, if one exists. But in old houses, this bus is often missing, or it is broken.
It is strictly forbidden to use water supply or heating pipes as grounding. Firstly, they may be plastic in some areas, which breaks the chain. Secondly, your neighbor on the floor above may receive an electric shock if you “land” a phase on the pipe through a faulty device. This is not only dangerous, but also illegal.
⚠️ Attention: The use of central heating or water supply pipes as a grounding conductor is prohibited by the PUE (Electrical Installation Rules) and can lead to electric shock to your neighbors.
Materials and tools for installation
To perform high-quality work on organizing grounding or checking an existing circuit, you will need a certain set of tools and materials. You should not save on components, since yours depends on it.
The table below shows the main materials that may be needed when installing grounding in a private house or modifying wiring:
| Material | Purpose | Requirements |
|---|---|---|
| Copper wire | Laying of a grounding conductor | Cross section of at least 2.5 mm² (for sockets) |
| Steel angle | Vertical electrode (contour) | Size 50x50 mm, length 2-3 meters |
| Steel strip | Horizontal connection of electrodes | Section not less than 48 mm² (4x12 mm) |
| Euro socket | Refrigerator connection point | Presence of contacts for grounding |
As for tools, you will definitely need a multimeter to check voltage and resistance, an indicator screwdriver, a set of screwdrivers, pliers and, in the case of installing a circuit, a welding machine or powerful bolted connections. To lay the cable in the wall you will need a wall chaser or a hammer drill.
Step-by-step instructions for connecting grounding
If your apartment already has a three-wire network, but the outlet in the kitchen is two-pin, it needs to be replaced. First, turn off the power to the apartment by turning off the circuit breaker in the panel. Make sure there is no voltage on the wires using an indicator screwdriver.
Remove the old socket. You will see two wires: phase and neutral. If the wiring is modern, there may be a third wire (yellow-green) that simply wasn't connected. Strip the ends of the wires and connect them to the new socket according to the markings: phase (L) - on the right or left, zero (N) - on the other side, grounding (PE) - in the central contact with the “antennae”.
Wire connection diagram in the socket:L (Phase) - Brown/Red wire
N (Zero) - Blue wire
PE (Earth) - Yellow-green wire
After connecting, carefully lay the wires in the socket box, secure the socket mechanism with screws and install a decorative frame. Turn on the machine and check for voltage. If you have a resistance tester, check the circuit between the grounding contact of the outlet and the grounding bus in the panel - the resistance should be minimal.
What you absolutely cannot do
In the pursuit of safety, people often make mistakes that make the situation even more dangerous. The main mistake is “zeroing”. Some “masters” advise switching the grounding contact of the socket to the neutral wire. Doing this is mortally dangerous.
If the zero breaks (which happens quite often in old networks), a phase voltage of 220 Volts will appear on the housings of all devices connected to the network. The refrigerator, washing machine and bathtub body will become one big electric chair. No machine will work in this situation, since the current will flow along the standard circuit, simply through the body of the device.
⚠️ Attention: Never connect the grounding contact to the neutral wire in a socket or panel unless you are 100% sure of the integrity and correctness of the PEN conductor wiring throughout the house.
Also, you should not leave the grounding wire just hanging or twisted with other wires without insulation. It must be connected either to the ground loop or to the PE bus in the panel. If there is no grounding at all, it is better to use Residual Current Device (RCD)which will turn off the power at the slightest current leakage, even without the presence of ground.
What to do if there is no grounding at all?
Install RCD with leakage current 10-30 mA. It will not create a grounding, but will instantly de-energize the network if you touch the energized body of the refrigerator, saving your life.
Checking the effectiveness of grounding
After completing all the work, you need to make sure that the system is working correctly. The simplest way is to visually inspect the connections and check for contact with a multimeter. However, to be completely sure, a measurement of the resistance of the grounding device is required.
For this, a special device is used - a grounding resistance meter. One electrode of the device is connected to the bus being tested, the second and third are driven into the ground at a certain distance. The device sends a signal and measures the resistance to current flow. If the value exceeds the standard (usually 30 Ohms for 220V), the circuit is considered ineffective.
Regularly checking the condition of the wiring and grounding should become a good habit. Once every few years, it is recommended to call an electrician to inspect the shield and check the reliability of the contacts, especially if the voltage in the house often jumps or the circuit breakers are knocked out.
Can an RCD be used instead of grounding?
An RCD does not replace grounding, but it significantly increases safety in systems without it. Grounding drains the leakage current, causing the circuit breaker to trip, and the RCD reacts to the difference in currents. In combination they work perfectly, but one RCD without ground will also save lives, just an electric shock (short-term) will still occur before shutting down.
Which wire is better to use for grounding?
The best material for a grounding conductor is copper. It has excellent conductivity and does not oxidize as quickly as aluminum. The cross-section of the wire must be no less than the cross-section of the phase wire in the circuit, but for household appliances 2.5 mm² is usually sufficient.
Is it necessary to ground the refrigerator if it stands on rubber feet?
Yes, definitely. Rubber feet are not a reliable dielectric, especially if there is spilled water on the floor or high humidity. In addition, static electricity and potential can accumulate on the body and be transmitted through hands touching metal parts of the kitchen or walls.
What to do if there are three wires in the socket, but one is broken?
It is necessary to de-energize the line, carefully embroider the wire in the wall, build up the missing section with copper wire of the same section using a terminal block or soldering (twisting is prohibited) and securely insulate the joint. If the wire is short, it is better to replace the entire cable section.