If you do not yet have a backup power plant, and you are only at the stage of planning and selecting equipment, then our articles “How to choose a backup power supply generator” and “How to use a generator: refueling, starting, running in and maintenance” can be useful sources of information on these questions.

Method No. 1: connecting the generator to the house via an outlet

The easiest way to connect a generator to your home is to “plug” it directly into an outlet. The principle of this method is very simple: if a power source is connected to the outlet, then the voltage will also be in the adjacent sections of the electrical circuit. To connect an electric generator to a home network using this method, you need to buy a cord with two plugs or make it yourself from a cable and two plugs from extension cords or worn-out household appliances. One plug is inserted into the generator socket, the second into one of the sockets in the house.

Attention: in some countries this method of connecting a generator is prohibited. Check local regulations or consult a certified electrician.

It should be borne in mind that connecting the generator directly to the outlet is only allowed if the house is completely disconnected from the general power supply system (that is, you must first “turn off” the machine in the input panel or unscrew the plugs). Otherwise, part of the electrical energy produced by your equipment will go “outside”. And when the power supply is restored, the winding of a generator connected to an outlet can easily burn out from oncoming currents (and not in a figurative, but in a literal sense - the risk of fire is extremely high).

Scheme of connecting the generator to the house through an outlet.

This connection method is only suitable for low and medium power generators. It is strictly forbidden to connect powerful power plants directly to an outlet due to the fact that some elements of the household electrical network may not withstand heavy loads. For example, a standard power cable with copper conductors with a cross-section of 2.5 mm2, which is used for installing an in-house electrical network with a voltage of 230 V, can withstand a load of no more than 4.6 kW (and an aluminum cable of the same cross-section can withstand no more than 3.5 kW). The load on a 16 A socket should not exceed 3.5 kW, and on a 10 A socket - 2.2 kW. Exceeding the specified values will cause the wires and connectors to overheat and melt, which may cause a fire.

Moreover, it should be taken into account that connecting a generator directly to an outlet will not always work as intended if the electrical network in the house is made according to modern rules using RCDs and separate circuit breakers for each group of consumers. It is likely that only a group of sockets in the network circuit to which the generator set is connected will have voltage, and the rest of the consumers will be “cut off” by the automation (however, it all depends on the type, design and characteristics of the protective devices and circuit breakers mounted in the distribution panel your house).

Considering all of the above, the method of connecting the generator directly to a household outlet should be considered solely as an “emergency” option. Constantly using this scheme is highly discouraged, and it is absolutely forbidden to leave such a “collective farm” unattended for fire safety reasons.

To connect the generator, you can use a socket pre-installed on the outside wall of a private house or garage.

Method No. 2: connecting the generator to the house through a switch

If the electricity goes out more than once a year, but more often, then it makes sense to “get confused” and slightly improve the home electrical network to provide a simple, reliable and safe way to connect the generator to the house. Modernization involves two actions: installing a three-position switch and laying an additional cable.

A three-position switch is a device for switching from the main network to the backup network or vice versa. Depending on the design, such devices are sometimes called changeover or reversible switches. They can also appear in online stores and electrical catalogs under the complex name “transfer switch I-0-II”. It is advisable to choose a switch that is mounted on a DIN rail in the electrical panel. It is built into the electrical system after the electric meter(so that the meter does not count the electricity produced by your generator). It is advisable to install an automatic switch (regular or differential with built-in overcurrent protection) between the generator and the switch - this will be safer and more reliable.

Wires (“phase” and “zero”) from the power supply network are connected to one pair of the upper terminals of the switch, and exactly the same pair of wires from the generator are connected to the second. The cable going to the consumers is connected to the lower terminals. By switching the switch, the customer can choose which branch the power will flow through - from the network or from the generator. The wires for connecting the backup power source are led outside the house (to the garage, barn or to the outer wall of the building) - to where the generator set will operate.

Scheme of connecting the generator to the house through a switch.

This method of connecting a generator to a home is relatively simple and inexpensive, despite the inclusion of an additional device in the power supply circuit. Therefore, it is most often chosen to provide backup power supply.

Popular gasoline generators

Method No. 3: connecting the generator to the house via an ATS unit

The two methods described above have a common drawback - each time there is a power outage, you must manually insert the plug into the socket or switch the switch, and then perform the reverse procedure when voltage appears in the network. The method of connecting the generator to the house through an automatic transfer unit does not have this drawback.

The ATS unit is a special automation kit that is built into the power supply system in front of the distribution panel or instead of it. The function of the automatic transfer unit is, as the name implies, to automatically switch between the main and backup sources of electricity. The AVR unit independently determines the presence or absence of voltage in the main network. If the electricity is lost, the automation reacts instantly and sends a signal to the generator to start via the control cable. The power supply has been restored - the automation turns off the engine and turns off the backup source of electricity.

Scheme for connecting the generator to the house via the ATS unit.

There are generator sets on sale in which the ATS unit is immediately integrated into the design (mainly stationary power plants) or included in the delivery package (as a rule, we are talking about mobile units). You can also buy a generator with a connector for the ATS unit, which is ready out of the box for integration into an automated system (but the automation must be purchased separately). All such generators have electric starters and batteries, thanks to which the equipment can be started without human intervention.

The method of connecting a generator to a house using an automation unit is the most difficult and expensive to implement. But such a solution is beneficial and fully justified if electricity is lost frequently.

Generators with autostart

230 V does not forgive mistakes

All methods of connecting an electric generator to a home network described above are in no way a guide to action. This article is for informational purposes only. It describes the general principles and gives an idea of what you need to buy to connect a generator to your home, and what changes you need to make to your household electrical system. But only specialists who have the appropriate knowledge and approvals should draw up a connection project and carry out work on installing a switch or automatic transfer switch unit.

Attention : When connecting a generator to your home, do not ignore common sense and safety regulations. Incorrect connection of backup power may result in network overload, short circuit or fire.