Conduit to allow for rewiring

[john4703]

Because the OP is only running conduit for the drops so he can do the chases and make good beforehand. Through the floor/ceiling space it's not going to be in conduit I don't imagine.

I was suggesting that he could make the job easier by doing it all in conduit. He would been to get his electrician to tell him how to run it all.

 

[DetlefSchmitz]

If you do all the calculations including grouping, the CCC of 2 x 2.5mm² in conduit buried in plaster is slightly less than 20A and so doesn't really comply for a ring final. So you could only ever try to put 1 x 2.5mm² through, and this is pretty easy.

 

[SUNRAY]

Not when it's 2 * 2.5mm²^2 which it invariably is.

Hence:

I will suggest that you run two 20mm or one 25mm conduit for ring circuits as getting 2x2.5mm² T&E into a 20mm tube from an awkward space is tricky. The same is true for more than 2x lighting cables.

 

[Celeronmanuk]

If you do all the calculations including grouping, the CCC of 2 x 2.5mm² in conduit buried in plaster is slightly less than 20A and so doesn't really comply for a ring final. So you could only ever try to put 1 x 2.5mm² through, and this is pretty easy.

Yes, it was for that reason that I put in 2 x 20mm conduit for each socket when we rewired as agreed with the electrician.

 

[DetlefSchmitz]

Yes, it was for that reason that I put in 2 x 20mm conduit for each socket when we rewired as agreed with the electrician.

 

[SUNRAY]

If you do all the calculations including grouping, the CCC of 2 x 2.5mm² in conduit buried in plaster is slightly less than 20A and so doesn't really comply for a ring final. So you could only ever try to put 1 x 2.5mm² through, and this is pretty easy.

I didn't think that is a problem when I did the calcs, but I haven't recheck for many years.

 

[DetlefSchmitz]

Well, it wasn't with the very latest edition, but try as I might, I couldn't (quite) reach 20A. I was pretty annoyed at the time and double checked.

 

[sparkwright]

I was suggesting that he could make the job easier by doing it all in conduit. He would been to get his electrician to tell him how to run it all.

Only the drops would be in conduit, to do the whole job in conduit and singles would be a nightmare.

There would be conduit everywhere under the floors, the modern home has so much wiring now.

Stick to T+E and conduit in the plaster.

 

[sparkwright]

Get the spark involved first. If it was done to me I'd rip the whole lot out again or more likely decline the job.

I think what Risteard possibly meant to say was:

Do the chasing, fit the boxes, but don't fit the conduit until the cables are in position.

(Pushing cables from under the upstairs floor down 2 or 3m length conduits fixed to the wall will wind up the most patient of electricians.)

Leave the conduit out of the chase until the cables are in place.

 

[Risteard]

(Pushing cables from under the upstairs floor down 2 or 3m length conduits fixed to the wall will wind up the most patient of electricians.)

I am probably in the top percentile of the most patient Electricians.

 

[sparkwright]

Same as me then.