Copper conduit

[bernardgreen]

Do the regulations permit the use of copper pipe as conduit for twin and earth cable ?

A friend is being told by an electrian that the replacement 10 mm cooker cable cannot be run in the copper tube ( 28 mm diameter ) that the damaged cable is run in. ( damage is elsewhere and the full run is being replaced) I would think that provided the pipe is bonded the rules for steel conduit would apply.


I have just tried 10mm cable in 22mm pipe and it looks like it is within the 45% limit. So 28 mm pipe would have plenty of free space.

 

[ColJack]

copper pipe is a lot softer than steel conduit and tends to be thinner wall so it doesn't provide the same mechanical protection..
the fitings are not threaded so unless you use compression or soldered joints there is no guarantee of earth continuity...
how would you protect against sharp edges of the pipe? conduit has male or female bushes to bo the job..

regulation 521-04-01 lists the relavent BS numbers that conduit must comply with...

it lists steel conduit and fittings, flexible steel conduit, steel conduit and fittings with metric threads, and non-metallic conduit and fittings...

so no, you can't use copper pipe as conduit...

although, it might be interpreted as a "ducting" which must comply with BS 4678 or BS EN 50085-1.. whatever they are...

 

[daytona]

if its buried in a wall or run in a void.i would not have a problem with it.yes copper pipe is not impact resistant but then neither is oval and we bury that in walls all the time.

you are doing it in twin and earth so continuity will not be a problem.i would'think of something' to stop any chaffing when it enters the pipe,grommet strip perhaps?

 

[jossper]

Sounds more like the electrician thinks he's going to have problems pulling the cable in to me. Hope its not got any elbows in it!

Could he not pull a plastic flexi conduit through it and then pull the cable through that? Then it would be in "proper" conduit, complying with the regs. It would just "happen" to be inside a copper pipe!

 

[bernardgreen]

The copper pipes, there are four locations but only one being worked on, were put in place when the ingle-nook stone work was being re-built. They have smooth bends in them, the original cables were pulled in without difficulty. The ends have been protected with some form of bushing and have "safety earth" bonding on them.

The suggestion of pulling in flexible plastic conduit will be put to the electrician.

The alternative is a 3 to 4 foot drill through a hard stone built wall.

 

[ebee]

Are the runs in "safe zones" , if so then copper is no problem providing that sharp edge and possibly earthing issues are addressed.

Ask if he would object to "Pyro" then ask why not this set up LOL

 

[daytona]

the kopex idea isnt a bad one but i dont think it will work.
you really need to do it in 25mm which only gives you 3mm tolerance to pull with.

why not phone the niceic technical support line and tell them about the copper pipe

 

[ColJack]

pryo has the copper sheath built round it.. the internal wires are seperated from it with powder which also adds to the copper sheaths rigidity and stops it from deforming as much if impacted..

totally different from dragging a wire through a copper pipe..

but as stated, if it's built into the stonework with little or no danger of impact damage then treat it as a duct, not a conduit...

as long as the client is made aware that if the cable is damaged in the pulling in then they are going to be charged for the damaged cable as well as any remedial work then I'd do it.. just so the sparky doesn't get hit for the cost of a length of 10mm if the cable gets damaged during pulling in..

 

[bernardgreen]

The electrician now accepts that the existing copper tube is acceptable as a conduit for the cable after

[1] soldering tags to the pipe at each end to which he could attach "earthing cables"

[2] driving short lengths of plastic conduit into the ends.