Hello, an S/FTP cable is already very well shielded, but it can still have an influence if it is laid very close or together with power cables. It also depends a bit on the shielding/insulation of the power cable. I would simply try it and connect it as a first test without laying it (I have already had new defective cables) - if it is ok, only then lay it and test it again.
Here is some more information on the structure of network cables: https://de.m.wikipedia.org/wiki...