Sometimes residents of apartment buildings are faced with an unpleasant problem when the voltage in the network either sags or rises: incandescent lamps give less light than usual or more than usual. This is a very bad sign – you have an accident on the neutral wire.


The tester will help to determine the presence of voltage on the neutral wire – if it shows the voltage in the network more than 240-250 Volts, then this is very similar to an accident. It is very useful to measure the voltage between the neutral wire and the ground wire. For a regular apartment or office wiring of a 220 Volt network, it should be near zero, if powerful loads are not included. So when you turn on a kettle with a power of about two kilowatts, the voltage will be about 2 volts, in other words, about a volt per kilowatt of the switched on load. The voltage between the neutral wire and the ground is more than 7-8 Volts – this is bad.


Dangerous voltages arise for several reasons:

– a break in the neutral wire;

– poor electrical contact of the neutral wire in the apartment (office) wiring, or in switchgear;

– large overload of one or two phases in the network, for example, when connecting a welding machine;


If the neutral wire breaks in the general house wiring, then the floor shield will remain without a neutral wire. In this case, the current flow circuit will close from one phase to another through the included household electrical appliances. At the same time, the voltage on the contacts of the outlet can rise up to 380 volts, which almost always leads to the failure of electrical appliances. In the best case, the fuse and lighting lamps blow out, and in the worst case, chokes, transformers and other electronic components overheat, which can lead to a fire.

Phase imbalance occurs when one or two of the three phases are operated with an excessively large load, and the third phase is underloaded, which leads to a voltage on the neutral conductor. The uneven distribution of the load over the phases is especially aggravated during peak consumption, for example in the evening.


Also, voltage occurs when an overload in the network and due to an increase in the resistance of the neutral wire, due to the occurrence of high transition resistances in the connections (twists, spikes, bolt clamps, etc.) or an insufficient cross-section of the neutral wire.


In such cases, it is best to turn off the apartment machine in the dashboard, which will de-energize all electrical appliances and call an electrician.

You can install a voltage relay that will turn off the home network in the event of a zero break, or a powerful arrester that will protect devices from short-term voltage surges.


And if you are not at home when this happens, but if this happens only from time to time – for example, sparking in twists, spikes, bolted joints, connections in sockets? How to fix this and prevent an accident in the future? If you have a BALANCE system installed, we offer a range of sensors on request for continuous monitoring and storage in the database of the state of your power grid.


To monitor the safety of in-house networks, an association or a power supply company can additionally install sensors:

  – Phase voltage loss sensors;

  – Voltage sensors on the neutral wire;

  – Voltage sensors on phases;

  – Sensors for arcing wiring (poor contacts).


The FRESH platform – organically complements the capabilities of the BALANCE system – allows you to track the position of objects, take into account the availability of objects, take into account the working hours of remote employees and use sensors built into a smartphone.


BALANCE mobile application for Android here:


More information about BALANCE on the website, and we will be glad to hear your recommendations at


PDF version