Cable Segregation

[1974stephen]

Hello All

A quick query regarding the regs re: cable segregation.

We are working on a site where there are 240v cables and CAT5 cables running in the same trunking. The electrician has said that because the CAT5 cables are being used to connect to a dimmable ballast that's rated at 240V it's OK to put them in the same trunking.

I thought that all cables running together needed to be rated at 500V if any of them were 240V? obviously CAT5 isn't rated at 500V.

They are certifying to 17th edition and apparently don't want any amendments. Is this OK?

 

[pukka]

CAT 5 Cable is rated to 50v if its in the same trunking it needs segregation, IIRC if running in a void it need to be 300mm apart but you can cross it at 90 degrees

Paul

 

[Chri5]

17th suggests 50mm seperation, as did BS6371 telecoms guide 20+ years ago.

Or a physical barrier, such as seperate compartment trunking- your right that x overs should be at 90 degs of bridged with a physical barrier.

Since there being used for contact, electrical I see no issue with them being bundled with 230v cables. If they were for data or comms, then the rule is per the 17th >50mm

 

[1974stephen]

The CAT5 is for a 10v dc control signal. It's being used for controlling dimmable ballasts on a lighting control system. My thoughts were that surely you can't have 10v dc cables (not rated at 230v) in the same trunking as 230v? If this is all OK, why do we bother having different trays instead of sticking it all on one big one?

 

[electronicsuk]

It's unlikely that you will experience any interference with 0-10v control systems, but I do agree that it is unwise to run 50v and 500v rated circuits together and it should be avoided if at all possible. Any insulation breakdown could certainly cause serious damage to the control desk and dimmers.