Just to clarify some points. 50 X 50 trunking is chosen because the plan is to drop cables from the trunking at ceiling level in conduit to sockets and switches and that size is convenient to work with when it comes to joining conduit to trunking.

The Cat5e will mainly be to connect to CCTV cameras using POE and a single computer port.

I am inclined to agree with Tim Watts having seen exactly the same done by profesionals and having previously installed dado rail trunking with both telecoms wires and Cat5e running in the separated channels, I noted that distance wise there was little separation between them and the mains wires and was never aware of any interference in either.

Richard