Cable runs

[Jimmy3]

I am running a 2.5mm twin and earth radial plug circuit from the top floor of our town house.
The easiest route to the ground floor where the consumer unit is is down a box section in the corner of the bathroom which is on the first floor, and then on down to the ground.
The only thing is the central heating pipes run down this box. Is this allowed in the IEE regs?

 

[PrinceofDarkness]

Jimmy, I suppose that you want to drop that 2.5mm cable down the boxing without opening the boxing to clip the cable away from the heating pipes? You'd probably get away with it - many have done so.....

But consider using 4mm cable.


Lucia.

 

[wingcoax]

Hi Lucia, long time no hear, I agree , Use at least 4.00mm

 

[SUNRAY]

Jimmy, I suppose that you want to drop that 2.5mm cable down the boxing without opening the boxing to clip the cable away from the heating pipes? You'd probably get away with it - many have done so.....

But consider using 4mm cable.


Lucia.

I would suggest using 4mm FP200 as an extra precaution as the heating pipes could be running fairly close to the maximum temp of T&E.

But its still not right.

 

[1john]

Best thing in my mind would be to drop a flexible conduit down to house the cable in.

 

[Jimmy3]

Thanks for all the pointers, however does anyone know whether the IEE regs allow this?

 

[SUNRAY]

Thanks for all the pointers, however does anyone know whether the IEE regs allow this?

I reckon running a cable in boxing with hot pipes does not actually contravene the regs perse as long as the spec of the cable etc is correct for the situation and it is calculated and fitted properly, this includes spacing of fixings on a vertical cable.

Best thing in my mind would be to drop a flexible conduit down to house the cable in.

I dont see how this would help.

 

[1john]

well it provides a barrier between the cable and the pipe work and conduit is an acceptable support method for the cable seeing as he wont be able to clip it.

I cant see how specifying a larger cable helps any of those two concerns?

 

[Jimmy3]

If i don't use this route, am i right is thinking the next best way is to channel a route within 150mm from any corner and then plaster over the cables afterwards?
Alternatively all the internal walls in the house are stud so i may be able to route it down one of these.
What does anyone think?

 

[SUNRAY]

well it provides a barrier between the cable and the pipe work and conduit is an acceptable support method for the cable seeing as he wont be able to clip it.

A cable with a higher working temperature will be required whether is in a conduit or not. The conduit will also be required to be fixed as per regulations.

I cant see how specifying a larger cable helps any of those two concerns?

Its called derating factors and the fact that 3 people make the suggestion.....

 

[ban-all-sheds]

conduit is an acceptable support method for the cable seeing as he wont be able to clip it.

Why is a cable dangling inside vertical conduit supported but cable dangling inside vertical trunking is not?

 

[1john]

technically neither are, same as cables in stud work really though, although I cant think of one instance when a 2.5mm or 4mm cable has ever slid out of a 20mm flexible conduit which is of any sizable length.

My sugestion was a solution to the problem of not being able to safely keep the cable away from the hot pipes. It is inexpensive and would be relatively simple to execute.

 

[SUNRAY]

conduit is an acceptable support method for the cable seeing as he wont be able to clip it.

Why is a cable dangling inside vertical conduit supported but cable dangling inside vertical trunking is not?

Good point, well presented.

 

[Jimmy3]

Thanks for all the inputs, however after mulling over it, i think it will be safer to channel the cable into the wall and then plaster over it.
Also please see my next post.

 

[SUNRAY]

technically neither are, same as cables in stud work really though, although I cant think of one instance when a 2.5mm or 4mm cable has ever slid out of a 20mm flexible conduit which is of any sizable length.

My sugestion was a solution to the problem of not being able to safely keep the cable away from the hot pipes. It is inexpensive and would be relatively simple to execute.

Indeed, I have no criticism of the proposal but due to the hot environment, as I wrote before, the cable will still have to be the same type whether in the conduit or not so there is basically nothing gained by adding the additional conduit.

Although not conforming to regs there are 1000's of installations of the type proposed by the OP and they are commonly missed on PIR's. I have even seen T&E and standard PVC flex cable tied to heating pipes, even right into big [300KW plus] boilers, the cable ties usually fail before the cable.