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Grumbling electrical meters and the dangerous open neutral - identify hazards in home electrical appliances


In the second part of our two-part blog series, Matti Lehto, operating manager of Oulun Energia Sähköverkko Oy, has compiled important tips such as how to identify a dangerous open neutral in electrical equipment, and how to ensure the safety of a switchboard. These simple guidelines should be kept in mind as part of home safety.

Identify a life-threatening open neutral

Perhaps the most dangerous defect in an electrical system is the open neutral. In an open neutral, the neutral wire of the power supply is disconnected or poorly connected. An open neutral can also be on the power supply side of the electricity company's network, when, for example, an overturned tree has cut the neutral wire of the overhead line. In the event of an open neutral, the devices start to work strangely: the lights turn dimmer and brighter, some parts of the house may have a dim light and others a bright light, or the lamps may even break down as a result of overvoltage. Electric shocks can occur in the shower, at the sink, or in similar places. In this case, immediately disconnect the power from the main switch without touching the metal parts, and call the fault report number of the electricity company. Electricity must not be switched on until an electricity professional has determined that it is safe to do so.

A professional to help from time to time

One recurring cause of fault reports to the electricity company is the sound of the electricity meter – it grumbles, so to speak. The truth is, the sound isn't coming from the meter. It's coming from the contactors. These are electromagnetic control switches that control the heating system, the water heater, or other equipment of the switchboard. When the contactor starts to come to the end of its life, the electromagnet in it will not be able to hold it tight enough and the device will start to make noise. The internal switches of the contactor do not stay closed properly, they form burn marks and start to warm up, eventually causing a fire hazard. These switchboard contactors are the customer's own equipment, and their replacement is the work of an electricity professional. A strong buzz at the switchboard is usually caused by a faulty contactor.

Cleanliness promotes fire safety

Few people are aware that electrical switchboards also need to be serviced. Cable connections become loose over time or may be loose due to sloppy installation. Due to the load, the connection becomes warmer, and the connection becomes even looser and hotter, eventually causing a fire. This situation becomes more aggravated if there is any accumulated dust or construction waste in the switchboard, such as wood shavings, which has never been cleaned up.

In terms of safety, it would be good if an electrician would check the connections regularly, clean the switchboard and, if necessary, replace the switches and contactors that are becoming obsolete. Cleaning of any electric radiators next to walls is also necessary. The radiator's resistor heats up, and it doesn't need dust to increase the risk of fire. The electrician can also easily perform a thermal scan on the connections, so that the risk factors can be clearly identified. At the same time, the electrician can check that the load is even and that there is no skewed load in the switchboard, where one part of the interface is unduly loaded compared to the others.

Read more about home electrical safety tips in the first part of Matti's electrical safety blog series.