The Electrical Thread

3x220 volts.

this is a fusebox(edit, last pictures attchement) partly assembled and finished.

The main switch has 3 inputs that come from the street, L1-3, these then get divided as equally as possible between the fuses for the most equal load.

The first 3 16 Amp fuses are for the stove, they combine into a 380-400 volt "strong voltage" plug that connects to the stove.

a house with electrical sauna will have a similar 3-phase 400 volt setup for the sauna, in most apartment buildings(the picture i gave was for a small apartment), only the main breaker room will have an extra 2x3 phase breaker box for the communal sauna.

here it is direct wall connections(stoves, sauna's etc) or cee for big equipment that is not permanent.

Until the mid 1990s, Europe was not unified in voltage. The integrated power grid was always 50Hz but different countries used different voltages. Countries ranged from 210V to 250V. Germany had 220V, Italy 210V, UK 240V. This is now all unified to 230V which is within the usual ±10% tolerance of most countries.

In the past, it was common to hook small buildings to a single phase only. In old villages you sometimes see every 3th house dark when there is blown fuse in the single transformer for the entire village. For rotary, you had to pay extra!

Most "rotary current" devices don't actually need rotary current, especially if it just heats. The internal parts all use 230V and each a maximum of 16A. Especially stoves are meant to be connected to single phase only for the old buildings without rotary power. A common stove has a connector box with bridges installed:



The classic stove is set up for 1x25A operation. If you have rotary current, you remove the bridges and run it 2x16A or 3x16A. Modern stoves are more powerful so you need 2x25A or 3x16A.

3x16A rotary is preferred since you can convey more power with less copper since the phases are 120° shifted to each other and the currents add up vectorial. The neutral and PE can't carry more current than a single phase alone can carry before the fuse blows. If the load is perfectly balanced, the neutral carries no current at all.

Old barns were often connected to the farm house by 3 blank wires for the electric motor powering the thresher and a circular saw for fire wood. No neutral (and no PE) necessary.

Our transformers are 240 V, not 120. They have a center tap which is tied to neutral. If you want 120 you go between one side of the transformer and neutral, if you want 240 you go across the entire transformer. If you have two equal 120 will loads, one from one side of the transformer to neutral and the other from the opposite side of the transformer to neutral, the neutral line carries zero current. If the two loads are not equal, the neutral line only carries the difference. If a large appliance, such as an air conditioning unit or water heater operates entirely from 240 V, you don't need a neutral line at all.

so you guys run one-phase distribution - as differentiated from single phase. your transformers step the 480V distribution to 240V for residential taps. here, they step 7000V down to a three wire tap that has 240V line to line and 120V line to neutral. a three phase service has 4 wire taps, which are either 480V or 208V line to line and correspondingly 277V or 120V line to neutral.

one of the factors here is that the larger the transformer is, the higher the available fault current in (the current the transformer will deliver to a bolted fault (a direct short circuit that won't burn clear)) and the service gear must be built to be able to open the AFC.

Actually, the Neutral of 3~ rotary is like the "in between tap" of the US 2~ system.

With a 3~ rotary current system, the lines are phase shifted by 120°. This has several advantages.

You can choose between two voltages while the voltage between phase and ground is the lower one.


The relation is the factor √3

230V * √3 = 398,37V ≈ 400V

The voltages add up vectorial. Since the US 2~ system is 0° (or 180° from the point of view of the neutral), the voltage of the two phases simply add up with simple arithmetic. With 3~ rotary, you need to add up vectorial. Fortunately, the vector addition can be replaced by a simple factor which happens to be √3.

The rotary current system doesn't use 3 separate transformers, the coils are linked by the iron core.



Another advantage is that you need less wires of same gauge to distribute the power.

And just like with the US 2~ system you need less insulation (to ground) and you can still make use of a higher voltage.

Also packing 3 coils into a generator instead of one or two is more efficient since it can generate more power in the same generator space. Same for the motors which are more powerful and can have a lot more torque due to the rotary field.

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The 400V is not the local power distribution, it is the final voltage of 230V. It's often called 400V in short but in reality its 3x230V or "230V/400V rotary".

480V is also used, in this case, it is 3x480V = 830V (phase to phase) and used for short distance distribution e.g. inside a factory complex. Each building has its own transformer (or more) in the basement. This is not so much for reducing transfer losses, the idea is to block interferences and DC from machinery. Large machinery usually has its own transformer while computers and lights are connected to another one, sometimes from the building next door.



The actual EU grid is 220kV for long distance or 380kV for very long distance distribution (top, power plant on the left side)

Heavy industry is usually fed 110kV or uses its own high tension plant directly connected to the grid of 220kV.
110kV railway is not quite right, they mean streetcars and subways since the "big" railway systems in central Europe use 16⅔Hz in an independent grid fed by special generators in the power plants.

The local distribution is done by 20kV, not just 2x7kV like in the US.

Time to create a thread for discussing various topics on electricity, maybe? You guys have been at this for 5 pages now. Just saying...