Trunking size for ring main spur

[DIYC]

Hi,

I'm putting a spur in to my upstairs ring main.

There's already some trunking on the wall which would be perfect for the spur cable.

My concern is whether or not the trunking is suitable for the cable?

The trunking is 25mm wide and 15mm deep.
It already has 1 length of coax in it and 1 length of alarm cable.

Can I put my new length of 2.5mm twe cable in there as well?
(I think it will fit, but is there enough space to distribute any heat the new cable might give off?)


Thanks.

 

[Spark123]

No, you shouldn't put a mains cable in there as it will be detremental to the other cables.

 

[DIYC]

So it sounds like heat is not the issue but the current flowing through the mains cable may interfere with the picture signal in the coax and worse (from an annoying point of view) the signal in my alarm cable.

I may yet re-route the other cables then and just put the 2.5mm spur cable in the existing trunking. If that was the case - is that trunking big enough?

Thanks.

 

[rebuke]

25mm is plenty wide enough, you could easily put two cables in it if you wanted to extend the ring rather than a spur or whatever...

 

[DIYC]

An alternative approach I'm considering is to drop the cable down the partition in the stud wall (behind the plasterboard).

To give you some background...
The spur socket is going in an airing cupboard.
The door to the airing cupboard is on the landing - so it's not in a bathroom.
I have power in the loft, so I want to drop down through the ceiling to a 13a socket.

My concern with this approach is.

The stud wall in question seperates the bathroom and the airing cupboard.
Currently there is a 6.5mm cable in that wall for the electric shower and 2 x 1.5 mm twe cables in there that go to a fused spur for the burgular alarm.

Is it ok to add 1 more A/C cable in there for my new socket?
Will the combination of A/C cables cause any problems?


Thanks again.

 

[conny]

Why not surface mount the socket in the airing cupboard and run a length of trunking up the wall to the loft. Saves any chasing out or trying to 'fish' a cable from inside a stud wall which will/should have noggins inside anyway.

 

[DIYC]

Yeah, I'm pretty happy to do that.

But that does raise another question (in my head).

How far apart should the two bits of trunking be?
Obviously as far as possible is a logical answer.

But I have a curious mind so if anyone knows a more scientific one I'd appreciate it.

The reason I ask is that if the A/C cable can cause noise to the coax/alarm cables (which are sheathed in plastic) when in the same trunking then to me it would seem that that interference could penetrate the walls of the trunking if I put the new run adjacent to the existing one.

Final question on this subject, is there anything available to shield the cables from the interference? I'm assuming I shield the alarm/coax cables rather that the A/C - just wondered.


Thanks again.

 

[RF Lighting]

I don't think there is any defined distance, but I would want 50mm minimum between mains and ELV.

You can install some form of earthed metal to screen the two different types of cable to prevent interference.