I've got Band I (CAT5e Ethernet and security alarm cables) and Band II (T&E cables for lights and ring mains) lying on top of thermal/acoustic insulation under a floor. I've keep them well separated, much more than 50mm, but in several places the T&E cables cross the ELV cables, and at the moment the T&E cables are just lying on top of the ELV cables where they cross. Not a problem in terms of interference I think, as the cables cross at 90 degrees, but is this acceptable in terms of safety / regulations, or should there be something placed between the Band I and Band II cables where they cross?