How to connect the generator to the network at home: diagram, basic methods, instructions
In the absence of electricity or failures in its supply, a private house needs backup power. Many homeowners are often puzzled by the problem of how to connect a generator to the mains at home. The scheme must be first and foremost secure. First of all, you need to figure out what not to do.
Errors when connecting a reserve
It is not allowed to connect a mini-power station to an outlet in the house when the machines in the input panel are turned off, which is often done by the owners. The power of the generator can be several times greater than the capacity of the wiring. For an outlet, it is no more than 3.5 kW. As a result, the wires will overheat, which threatens with a short circuit or fire. If someone accidentally turns on the machine when the power is restored, the backup power source will immediately fail. But there is still a solution to the question of how to connect the generator to the house network through an outlet. The mini power plant can be connected to the home switchboard if it matches the load power and is connected only to the switch contacts on the generator side. The correct solution would also be to connect an extension cord to it, and then the necessary devices. In this case, the backup source will not be connected to the home network.
In case of frequent power outages in the country or in a country house, it is recommended to connect the reserve using a toggle switch, a reversing switch or an automatic reserve start system (ATS).
Generator selection
A home power plant is an internal combustion engine (ICE) that spins a generator that produces electricity. Typically, four-stroke models are used with a frequency of up to 3 thousand revolutions per minute. Household models are supplied with fuel tanks with a capacity of 10-15 liters.
The main issue when choosing is the purpose of the application. The generator can be the main source of electricity, but most often it is used as a backup when an emergency occurs on the line.
The main parameters are power, motor resource and economy. It is also important that the device is reliable and easy to use.
Connecting a gas generator requires the coordinated work of three elements:
- reserve cable;
- centralized power supply chain;
- home consumption network.
Main goals
When connecting, determine the following:
- location in terms of economy and safety;
- how often does a power failure occur and whether automation is needed;
- power consumption, taking into account losses and the choice of stock.
It is important to create a suitable connection scheme for your home network. Process automation is expensive and requires skilled maintenance. The most sparing mode for an individual house is manual connection. It also makes sense to use partial automation here, since semi-automatic devices will be inexpensive. Whatever the connection option, supervision of the system operation is required everywhere. Uninterrupted power supply is expensive and is not necessary for a private house. As a last resort, you can install an uninterruptible power supply on a computer or other important consumers.
First of all, you should calculate the required power of an additional source of electricity. To do this, the power of all loads that should be connected is summed up, after which a margin of up to 30% should be added to it. This takes into account the starting currents of home appliances motors, which are several times higher than the permissible ones. After that, the unit is selected to the rated power.
Example: a washing machine consumes 2 kW per hour, an electric stove - 3 kW, a refrigerator - 0.5 kW, a TV with a computer - 0.5 kW, lighting - 0.5 kW. In total, 6.5 kW comes out, and taking into account the margin - 8.5 kW. The operation of the generator is adversely affected by the lack of load. It must be at least 30% of the nominal value.
When deciding how to connect the generator to the network at home, the diagram is very important and must be drawn up correctly. For a minimum number of consumers, compact models with a capacity of 2-3 kW are used as a temporary measure until the main network is restored.
The scheme for connecting a gasoline generator to the network at home can be the simplest. It is important that it is drawn up correctly and ensures that the unit complies with the current load.
Types of generators
As domestic sources of electricity, gasoline generators are most common. Their features are as follows:
- a large selection of prices;
- low power - 0.8-12 kW;
- compact mobile and stationary models;
- there is a generator 3-phase and single-phase;
- predominantly four-stroke internal combustion engines are used.
Choosing the option of how to connect the generator to the network at home, the internal combustion engine cooling scheme depends on whether the unit is used permanently or temporarily. Usually devices are supplied with air radiators. Industrial models are capable of running around the clock on liquid cooling. They are produced mainly three-phase. They are larger in size but more economical.
Connecting a diesel generator to the network in the house is less common due to the high price. But still, its use is advisable because of the large resource.
Model types
Installations generating electric current are divided into types.
- Asynchronous. The design is simple and reliable. Important components are protected from moisture and dust. It is preferable to use devices for active loads. It is not recommended to use asynchronous generators to power electric motors.
- Synchronous. Aggregates do not have the disadvantages of asynchronous ones. In addition, they provide a more accurate voltage. You need to choose a brushless design, which has significantly better current characteristics and less radio interference.
- Inverter models are more expensive and have less power. The characteristics of single-phase devices are worse, especially for cheap models. A 3-phase generator is somewhat better. Other disadvantages are high cost and less reliability.
Single-phase and three-phase generators
If there are no three-phase consumers, it is advisable to choose a simpler model so that the power is used rationally. Connecting a single-phase generator to a three-phase network at home is not so difficult to do. In addition, a three-phase unit is more expensive and all phases should be evenly loaded. If the difference exceeds 25%, the device may fail.
For the reserve of a private house, a single-phase current source is preferable for any input.
Wiring diagrams
You can choose from several ways to use additional power supplies.
- Connecting the reserve to a dedicated consumer group according to a separate scheme.
- The use of a toggle switch or a three-position switch, on which jumpers are made at the input from the generator side. In this case, the entire home network will be powered. The disadvantage is that three-phase consumers will not work here.
- Installation of two contactors, where one connects power from the city network, and the other from a backup source. The method is used in schemes with ATS. It also requires jumpers between inputs on the redundant side.
Connecting a three-phase generator to a three-phase network at home must be done if there are appropriate electrical receivers, for example, electric motors of machine tools.
Generator auto start
The most complete way to switch the load is made using ATS. The system is equipped with an electric starter. The autorun device controls the external network immediately after power is supplied to it. Before connecting the generator to the network of a house with auto start, the automation waits 10 seconds after a power failure. Then the external network is turned off and the start of the diesel generator begins. After a set of revolutions for 20 seconds, the generator is connected to the network of the house.
When the voltage in the external network is restored, the reserve is turned off and the home network switches to normal operation. Then the generator engine is turned off.
Connecting a generator with an ATS to your home is a convenient, albeit expensive, solution.
The use of a toggle switch
If the middle contacts of the switch are connected to the consumer, and the extreme contacts to the power plant cable and to the power supply input, the power supply circuits will never intersect. It will be even better if the knife switch has another intermediate neutral position.
The initial state of the switch is considered when the main network is connected. When it is switched on, power begins to flow from the generator.
The disadvantage of the old-style toggle switch is sparking and openness of current-carrying parts. Modern designs are equipped with a protective casing that covers moving parts. The switch is fixed in the control panel. The starting position is the connection to the main network. In the event of a power failure, the shift knob is set to the neutral position, and then the generator is started, warmed up and connected to the loads in the house.
Separate load connection
Generators usually do not provide power to the entire household network. It is enough to connect the main consumers: lighting and some household appliances. It is advisable to rewire the wiring so as not to make many switchings. To do this, it is enough to draw a separate line to the emergency lighting and the refrigerator, TV, and computer sockets separate from the home network. A terminal block is installed in the shield, to which the cable from the generator output is connected.
Reversing switch
Switching to a power supply from a gas generator is carried out using a reversing knife switch. The device usually has 3 handle positions, where the extreme ones close the circuits, and the middle one opens.
A single-phase circuit is suitable for connecting a backup generator to the network of a house with low power consumption, for example, in a country house.
The input terminals are on the top and the output terminals are on the bottom. Indicator lamps are installed on the shield, signaling the inclusion of a network or generator.
Application of the ATS system
An automatic start system is much more expensive than a manual start system. In this case, external control is still necessary, since when starting the internal combustion engine, it is necessary to control the throttle. After starting, the engine should warm up.
Many prefer to use partial automation, with the main power connected through a contactor that opens when the input is turned off. The generator is then started manually. A time relay is built into it to warm up the engine and automatically switch to connecting a reserve to the house.
When the electricity supply is restored, the contactor is disconnected and the load is again supplied to the general electrical network.
The reserve with full automation of power supply contains microprocessor control of the operation of powerful generators.
Features of connecting generators
- The standby generator should be adequately protected from rain. This can be a canopy on the site or a separate room with exhaust gases.
- Installation after the meter, so as not to pay for your own electricity generation.
- It is possible to use the reserve as make-up during peak loads.
- The choice of an economical scheme so that there are no extra costs.
Conclusion
With an unstable power supply to a private house, a problem arises regarding how to connect the generator to the house network. The scheme should be simple and secure. The most convenient source of backup energy for an individual house or cottage is a generator with an internal combustion engine. The unit is convenient to transport and operate, it is not very expensive. To select the optimal connection scheme, it is necessary to familiarize yourself with the features of the device and switching equipment.