Crossing two 230V cables

[Nemo2000]

As part of alterations inside my airing cupboard I need to relocate the light fitting. The existing cable (1.0mm T&E) is laid on the surface of the wall and held by clips. I intend to remove the clips, move the cable, and put it in 16x16mm trunking for neatness.

However, the new route for the cable will take it at right-angles across the existing 2.5mm T&E cable feeding the immersion heater (also surface fitted). The bottom of the new trunking will serve as a physical separator. Are there any other requirements that I need to take into account?

The immersion heater circuit is rarely switched-on, only for odd emergencies. The light will have only intermittent use. It would be very rare for there to be power in both circuits at the same time.

 

[sparkwright]

Don't worry about it, it's fine.

 

[feynman]

I have never heard of this as being a problem - wires in and leading from your consumer unit no doubt cross each other in places, as will wires under your floors.

It could be a problem if you were routing low signal level cables, such as AV cables or computer or alarm cables near mains cables, but two mains cables would barely affect each other.

 

[oldbutnotdead]

Not a problem but don't crush the 2.5 with the trunking. Loads of solutions- if it's a plasterboard wall put a divot in the wall where they cross, space the trunking off the wall by 6mm or so, cut out the bottom of the trunking where they cross.....

 

[conny]

Or put a tee piece in the trunking and take the 2.5mm down to the immersion inside the down piece of trunking.
As stated above, 2 cables crossing will have no adverse effect on either of them.

 

[Nemo2000]

Thanks for the advices. Fortunately there is a bit of slack in both cables to give 'air room' between the two - no danger of squashing - but I just wanted to check that I'd not missed something in the Regulations.

Ironically I used to install network cabling as part of my 'day job' , so I'm well aware about cross-talk and interference etc, but the 230V supplies were always done by the local 'sparks

 

[plugwash]

There are grouping calculations in the regs for how much current carrying capacity should be reduced when when cables for different circuits run together, but

1. I doubt most electricans would consider it approrpriate to apply them in situations where wires simply crossed, rather than running together for an appreciable distance.
2. IIRC the grouping calculations say a cable carrying less than a third (or maybe it was 30% not sure) should be disregarded, a cable supplying a single light almost certainly falls into that category.

 

[JohnW2]

However, the new route for the cable will take it at right-angles across the existing 2.5mm T&E cable feeding the immersion heater (also surface fitted).

As has been said, that's not a problem at all. If there were ever going to be any theoretical 'issue', it would be when two cables ran in parallel for a long distance - 'crossing at right angles' is of no importance/significance at all (and, as has been said, would not even be considered to represent 'grouping' of cables).

Kind Regards, John