An electrical fault that is unfamiliar to many can even kill you – You can recognize the danger from these signs

A week ago on Sunday, a small house area in Espoo woke up to a scary electrical grid failure situation, which caused electrical devices to behave strangely.

The resident of the house describes waking up in the morning to strange knocks and strange noises, as if the house was haunted.

The reason soon became clear: the electricity network company Caruna’s sent a message warning of a potentially life-threatening null error.

The incident that came to the attention of Kauppalehti’s editors affected about 25 customers in the area, and it damaged several residents’ electrical equipment.

Kauppalehti has seen the error notification sent by text message and other related messages. The cause of the fault is thought to have probably been loosened connections over time, as a result of which the neutral conductor has gotten hot in the housing company’s technical space.

Caruna tells Kauppalehti that it does not comment on individual customer issues publicly, but can comment on zero defects on a general level. The failure of the small housing company in Espoo was not caused by Caruna’s network.

Can be life-threatening

Operations Manager at Caruna Jarmo Strömin According to In this case, a zero-failure situation can occur, for example, as a result of a storm: a tree that has fallen on top of power lines can break the support rope of the hanging coil cables of the low-voltage grid, i.e. the support wire of the AMKA line.

In cities and urban areas, the fault is less common. Typically, the cause lies in a broken or poorly connected neutral wire.

In a three-phase electrical system, the neutral wire refers to the conductor through which the electric current flows back in the direction of the power source, closing the circuit. The other conductors are the phase conductors, which bring voltage to the electrical equipment, and the protective conductor, which protects against electric shock in the event of a fault.

In the event of a fault, the voltages of electrical equipment can change dangerously. It can break the equipment. In the event of a fault, fault current traveling the wrong way or the connections heating up can also cause a fire.

The voltages of electrical equipment can rise up to 400 volts or fall to a lower than normal level. In electrical engineering, we talk about the displacement of the zero point. Normally, the electric voltage of the socket is about 230 volts.

As a result of the shift of the zero point, there is even a danger of a life-threatening electric shock hidden in the zero fault. In the event of a fault, the electrical voltage can in principle be transferred to any electrically conducting surface, which is why a fault report of a zero fault should always be made and a text message warning sent by the distribution network company should be taken seriously when one hits the spot, says Ström.

Caruna’s operation center monitors the electricity network around the clock and receives alerts from, for example, electricity meters or customer notifications. Typically, information about a power grid failure reaches the company quickly.

Do this in a zero fault situation

A zero fault situation can be recognized by the atypical behavior of electrical appliances in the home. Like the case in Espoo, a crackle or bang from the power station can indicate a zero fault. In addition, the room may smell burnt.

The stove or hot water heater may work more efficiently or less well than usual, and the brightness of the lights may vary, especially when other electrical appliances start up.

Caruna advises that in the event of a fault, the resident should turn off the electricity at the main switch using, for example, dry leather or rubber gloves.

The metal frame of the electrical switchboard may be live. For safety reasons, Caruna also instructs you to open the electrical cabinet and touch the main switch with only one hand and the other hand in your pocket.

The danger of electric shock lies in all surfaces that can conduct electricity. Typically, these are metallic and moist surfaces: touching the counter or water faucet should be avoided in a zero fault situation. Even a damp space like a bathroom can be dangerous.

Although the risk of fire is the most common in these cases, the risk of electric shock cannot be ruled out.

“Fortunately, the cases that have come to my attention have been fortunate in the sense that there have been no personal injuries,” says Ström.

When the electricity is cut off, it is safe to be in the property.

The electrical network inside the house is the owner’s responsibility

The responsibility for any damage caused by a fault situation lies primarily with the homeowner. Liability for compensation is then a matter between the resident and the insurance company. The exception is situations where the fault has originated from a fault in the network of Caruna or a similar electricity network company.

Electrical connections can loosen or corrode over time. In any case, it would be a good idea for an electrician to inspect the technical condition of a housing association or a single-family house every 5–10 years, Ström advises.

“At least the insurance company likes it when an inspection like this has been done,” says Ström.

According to Ström, the devices are safe to use if they function normally. If plugging the device back into power blows the fuse, the device is probably damaged. Typically, for example, fine electronics found in many electrical devices, such as smart screens, can be sensitive to atypical voltage fluctuations.