If both the data and power cables are shielded they can be run together without issue. If either cable is un-shielded however there should be some separation.
The following can be used as a guide to the required separation although there are other factors that can affect potential interference so it's advisable to seek the advice of a qualified electrician.
|Unscreened power / Unscreened data
|Unscreened power / Screened data
|Screened power / Unscreened data
|Screened power / Screened data