- Single-phase network
- Three-phase network
Single-phase network
If the power of the device is small( maximum 7 kW), it can be connected to 220 V. In this case, it is recommended to drive the phase through the breaker, and zero directly from the bus of the switchboard. It is also necessary to connect the ground to the water heater housing to protect yourself from electric shock.
So, the simplest electrical circuit for connecting an electrode heating boiler is as follows: 
A magnetic starter simplifies the process of controlling the equipment. When the temperature on the thermostat exceeds the set point( or vice versa falls below), the magnetic starter will switch on / off the electric boiler. This is very convenient and allows you to make the heating system automatic.
To the heating system, the water heater is connected as follows: 
Three-phase network
If you want to connect an electric boiler of high power, you must use three phases. The connection diagram of the ion boiler for 380 volts should be as follows: 
Here the wiring layout is a bit more complicated. As you can see, the three phases first go to the automatons, and from one phase conductor a wire was made to a separate single-pole automatic machine that serves the circulation pump. From the circuit breaker, the power goes to the magnetic starter, and from it to the terminals of the boiler. Zero conductor is connected to each device separately: pump, thermostat, water heater. Do not forget about the grounding, it must be connected by hand to a special terminal on the body.
Several popular connection schemes You can also view the video:
If you are interested in the connection scheme of the electrode boiler as a backup source of heating, then we recommend you familiarize yourself with this installation: 
The wires are connected in one of the above ways, or to 220, or to 380 V. We also recommend viewing the video, which clearly shows the entire installation process:
network. Here we have provided the typical schemes forSwitching the electrode heating boiler to electricity and the heating system itself. The popular manufacturer of water heaters - the company Galan recommends in a three-phase electric network to conduct each phase through a separate single-pole automatic machine. Thus, it is possible to manually adjust the heating power by disconnecting, or vice versa, including power to each electrode.
Also read:
- How to make an induction boiler by yourself
- How to make a self-heating apartment
- Wire color coding
