If you see main distribution board in building, you'll see 4 wires coming from substation and 5 wires outgoing to consumer. How it is possible? 
<ul><li>-There comes 4-wired cable where 1 is wire is PEN (earth and zero combined to 1 wire) and PEN seperates to PE (earth) and zero (neutral) pole on the main earthing block of terminals (left copper bridge between busbars).</li>
<li>Length of it could be variable, cause you can put short block of terminals to connect wires you are using nowadays; but if you have lot of money and don't know where to spend it, you can put block of terminals with 100 or 200 terminals (if distribution board's dimensions allow to put it).</li></ul>
<a href="//commons.wikimedia.org/wiki/User:Dmitry_G" title="User:Dmitry G">Dmitry G</a>
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