5kV power cable & Copper Communication run near together

[GoPackersGo]

Trying to design something that runs 5kV power cable for lighting that is run off of a Constant current regulator in a seperate conduit but near some 25 pair copper communications wire. Is there any minimum distance that I need to account for the not worry about harmonics or interference with the communication cable?

 

[Speedskater]

Modern communications systems are very resistant to AC power harmonics or interference.
But being close to a 5000 Volt cable is another matter.

 

[cabledawg]

Any chance to push to 25 pr out of the way? How's the 25 pr mounted/strapped up? And the space your in?