Cable trays?

[Alan Ambrose]

OK another tech question...

 

We have a 50mm services void. I was planning to run horizontal cable trays, mostly high-up (2.5m above the floor) and split into mains & ELV / data (either using one split tray or two separate trays). Then a few vertical drops to light switches etc, also in trays if I can. And then fill any remaining void with, say, mineral wool.

 

Question is - how do I avoid the mains crossing the data or is that OK? Something like this:

 

Mains ------------------------!-------------------------------

Data   ------------------------!---------------!----------------

                                                  !                         !

                                                  !                         !

                                       Mains Socket     Network Port

 

 

[garrymartin]

Perfectly fine. Crossing has fewer issues than running in parallel, and even that is not a big deal given the number of cables and voltages we are talking about in residential construction.

[ProDave]

BUT electric cables must tin in safe zones.  So to ensure this the electric cable tray must be within 100mm of the ceiling all the way across the room.

 

The data cable tray can be at any height you want.

[Alan Ambrose]

>>> the electric cable tray must be within 100mm of the ceiling

 

Ah, I was assuming some common sense on this  - we’re vaulted pretty much everywhere with a slopey ceiling from about 3.5m at the eaves. I was planning on putting the trays above the doors at about 2.4m.

[Alan Ambrose]

p.s. I was thinking re safety standards / British standards / building control etc rather than interference problems. I see a typical summary e.g. here:

 

https://www.cablemonkey.co.uk/cmdocs/ElectricalDistance.pdf

 

But it has so many cases, it’s really hard to follow.

[ProDave]

1 hour ago, Alan Ambrose said:

>>> the electric cable tray must be within 100mm of the ceiling

 

Ah, I was assuming some common sense on this  - we’re vaulted pretty much everywhere with a slopey ceiling from about 3.5m at the eaves. I was planning on putting the trays above the doors at about 2.4m.

Electric cables in a wall must run in a safe zone.

 

Broadly speaking a safe zone is horizontally or vertically from an electrical accessory, e.g. a socket, or within 100mm of the corner of a room or ceiling.

 

If you want to run electric cables around a room then do so at socket height, and ensure each wall has at least one socket to create that safe zone, and that is where all your mains cables can correctly run around a room.

[Alan Ambrose]

@ProDave So, I just need to put a dummy 'point, accessory or switchgear' to establish a zone / cable tray anywhere I like? 😄

 

I'm sure I need some temperature/humidity sensors up at 2.4m 😉

 

[ProDave]

Yes that is exactly what you need to do.

[-rick-]

Or cap the tray with 3mm steel?

[Nickfromwales]

Why cable tray? Lots of expense and faff. 
 

All round patent band is fine for bunching and laying, and clips are less time consuming than hundreds of cable ties. 
 

Seems a massive ball-ache and cost for very little practical return? You’ll need spacers behind the trays to get cable ties in / out, so further projection outwards too. 
 

Rows of 38x 25 and 38x 16mm trunking would be quick and simple, using the self adhesive to lay these out and then a few mechanical fixings to corners and joints where you’ll be pulling on them.