Staying in zone with kitchen socket run with a cooker switch

[username_given]

I'll start by saying - I have absolutely no intention of doing any wiring or anything electrical myself. You get someone professional to do a professional job - I know that. I just want to understand what I should consider so that I don't end up having to rip out or rework stuff afterwards.

The house in question is empty from 1930's and requires everything being done to it. Consequently everything is being ripped out. The kitchen was done in 1992 (from the wonderful newspapers under the lino) and at the time had a normal setup of a new kitchen ring put in - except the electrician couldn't get the return through the wall from the bathroom so it's a sort of radial with a load of spurs with the deserted unused return left in place. The majority of wiring in the kitchen was clipped visibly on the wall behind the units. It's all going - well gone. The whole house is going to have a full rewire - but we will get the whole house done once all the work is done.

I am currently chasing out the new runs for the cabling in the kitchen and as a bit of overkill am using FSU flexicon in the chases to the boxes so I can put everything in place and the electrician just needs to pull the new cables through and between the boxes with no agro - but we can do everything else like the kitchen install and tiling before that happens. I know the zones, everything runs correctly vertically/horizontally from all sockets.

So my question is with the wall with the cooker/hob -
The wall is basically a run of a double socket (vertical run up to it from floor then horizontally to...) > dp switch for hood > hob is here (300mm gap to electrical stuff either side)> oven switch > hob switch > double socket (horizontal to the next wall). The radial (why bother with rings now) will run straight along that wall. Both the oven and hob switches I want to run a separate conduit from the fuseboard so they can support whatever is needed (up to a 32amp switch) - so those will come up in zone from the floor under each switch.

My question is around where they cross - I can't take the radial past those two 32amp switches in zone as going above or below those switches goes out of the safe zone. I could drop it down under the floor and bring it back up the other side but it's a bit of a faff to have a conduit run like that.
I don't think technically there is anything against running the radial through those two boxes (and they can happily be 47mm or more if needed) but I know many electricians dislike it. I could run it just over the box out of zone but it won't quite be 50mm under the finished surface so it has to have metal conduit protection and I believe from researching flexible metal conduit doesn't count - it has to be solid. Again not necessary an issue.... but I do want all my sockets and switches in align.

I don't have an electrician yet to do the final rewire so I'd like the best chance of not having people go - err no mate not liking that - and having to find someone who is happy with the conduit runs.

So great members of this forum - what would people recommend on the routing?

(and yeah conduit maybe overkill - but I'd rather do it now and make any future rewires dead simple and just a case of pulling it all through. Sure many people would disagree and say it's a waste but it's what is happening )

 

[westward10]

Run separate vertical runs, running cables through back boxes is a bad idea and suggests a lack of forward thinking. Get an electrician on board before you do anything and let them design the cables routes. Not all but some maybe happy for you to do the graft but few if any will happily run cables through your intended routes as they are signing it off and your proposals may suggest they are incompetent.

 

[James]

Bear in mind that all cables will likely require rcd protection
flexible conduit is not considered to be an earthed containment, even though fsu has a steel inner core.
having worked for 2 major conduit manufacturers, I can tell you that in tests strangely the fault current generaly follows the spiral of the conduit instead of the direct path so a 1m of 20mm flexible conduit has an earth return path in the region of 6m of 3 sq mm steel.
if you want to run conduit, I would use fpp, it is flexible corrugated polypropylene and will be fine for the job. 20mm for switch drops or radial sockets, 25mm for ring sockets or cooker/shower etc.

 

[westward10]

Assuming this is a dwelling the installation method is probably irrelevant regarding additional protection for the lighting and socket circuits.

 

[nicebutdim]

I am currently chasing out the new runs for the cabling in the kitchen and as a bit of overkill am using FSU flexicon in the chases to the boxes so I can put everything in place and the electrician just needs to pull the new cables through and between the boxes with no agro - but we can do everything else like the kitchen install and tiling before that happens. I know the zones, everything runs correctly vertically/horizontally from all sockets.

I tend to avoid using horizontal zones unless absolutely necessary as it's hard enough to keep other trades from drilling into vertical zones and few trades people know about anything other than vertical zones.

but I do want all my sockets and switches in align.

Set the boxes where they need to be and bring cables to them - from what you describe the only reason for cables crossing is avoidance of necessary work. I don't see the point in replacing one lash up with another for the sake of a little effort.

I don't have an electrician yet to do the final rewire so I'd like the best chance of not having people go - err no mate not liking that - and having to find someone who is happy with the conduit runs.

You need that electrician before you start any work.

(and yeah conduit maybe overkill - but I'd rather do it now and make any future rewires dead simple and just a case of pulling it all through. Sure many people would disagree and say it's a waste but it's what is happening )

In NI we don't bury any cables without containment, so its use doesn't seem the least bit wasteful to me, but the idea of flexible conduit from board to each point seems rather unusual. It provides little to no measure of future proofing as it would be nigh on impossible to pull a replacement flat, insulated and sheathed cable through the stuff. I also wouldn't bury it in a floor or wall without cables already in place - at least not unless you're talking about very short, straight runs. It can be tough enough getting new cables through straight runs of solid conduit.

I may have picked up your intentions incorrectly, but it sounds very much like the sort of job most electricians are going to walk away from. Get someone on board before you do any more work and find out what they're prepared to work with.

 

[username_given]

Thanks for those tips. It is 20mm for the radials, and 25mm for the cooker. Shower is non electric, that'll be off a cylinder/ASHP.
"flexible conduit is not considered to be an earthed containment, even though fsu has a steel inner core." - makes sense I sort of assumed that's why the requirement of the solid conduit so get that.
100% it's a dwelling - but the board will get replaced (although it is fairly recent I'd still put it at probably 10yrs+) and as the gas it getting cut off and we will be going full electric I'd like to get it all properly up to date. It's RCD in plastic fusebox now, it'll by RCBO or whatever is the current regs when replaced - it's the proper FSU-P connectors into metal backboxes and wouldn't mind any earthing arrangement that needs to be done there.
To be honest I can't really get an electrician on board at the moment as it's going to be probably at least 18months before I work through everything around the house and have the money to get it done properly. Even if I found one and go them round, the likely hood of it all happening and being able to get them to our (lack) schedule seems unfair - at least for the kitchen. It's not a problem really as we current do not live there and wouldn't until this is done.
I could get FPP later, but have a load of FSU to use and make the most of - but I do take your point and noted.

Really appreciated the pointers tho and help, really do. Sounds like I'll probably drop under the floor and come back up the other side.

 

[username_given]

@nicebutdim - sorry got that after my post. Yes the runs are really really short - it's a very small house tbh - the whole kitchen is 2.8m x 2.7m. Horizonal runs are only along the worktop sockets. Not elsewhere

 

[OnlQQker]

If you are thinking of an outside shed/workshop/Ev point (etc) in the future, this is a good time to think about that as well.

If the downstairs is an Old wooden floor under the lino/newspaper, try and make sure the joists are not rotten, these might not be visible.

My son moved into a 1930's house 3 years ago and the washing machine went straight through the kitchen floor when it reached fast spin, I probably shouldn't of laughed cuz I ended up having to fix it all!

 

[username_given]

Obviously not a building/DIY forum so will keep it short but yes - we've taken all the floors up. Several joists in the bathroom need doing as well as the kitchen. Will all be insulated with breathable insulation and made wind tight (partly why I want to do conduit as we don't want leaks and want to be able to rewire in future without destroying it all).

I've thought about running something to the front of the house, it's probably only 4-5m from the fuse box to the wall to have a front charging point. But it would need to be some sort of "conduit" so the cable could be put in later once all the work is done - and so it could be replaced in future as it's going to be a forever bungalow. Same with at least a socket outside at the back (about 4m again) - gardens not really big enough to have a shed Considering the views above on conduit tho I may leave it - we could for now go up and over through the roof for both but at some point we want to go into the loft. We are just focusing on the kitchen for now - everything costs so much money!