The Russian wrote:
But now there is another problem..when I unplugg the power plugg to the Pi it doesn´t stop it keeps going...it must be getting the power trhough the USB cable from the hubb,is this how it should be?I mean I have a bipolar PSU to power the Pi and the PSU to the hubb is switched....
About half of all "low-to-medium-cost" USB hubs "back-power" AFAICT (see here: http://www.cpmspectrepi.webspace.virgin ... esChk.html
for those I've tested). Some folks use this "feature" (strictly, it's not allowed by the USB specs.) to power their Pi's and accept the risks associated with having by-passed the Pi's own protection circuitry (polyfuse etc.).
Still running Raspbian Jessie or Stretch on some older Pi's (an A, B1, B2, B+, P2B, 3xP0, P0W, 2xP3A+, P3B+, P3B, B+, A+ and a B2) but Buster on the P4B's. See: https://www.cpmspectrepi.uk/raspberry_pi/raspiidx.htm