Morning folks. Currently renovating the kitchen and I’m after some advice on the best way to run power to a kitchen island for a couple of sockets, lighting and a dishwasher. Floor construction is type 1, sand blinding, DPM, PIR insulation. There will be another layer of DPM and then 65mm concrete screed. Before we concrete, should I use this opportunity to get the spark to lay conduit in the PIR? Or is it best to run it through the concrete slab? Any suggestion on the best type to use? 50mm conduit in 65mm screed could cause issues? Cheers!
Definitely run the conduit, along with a pull string so the spark can pull in whatever he needs. Make sure it's big enough in diameter to pull two 2.5mm2 twin and earth's and maybe a bit extra. I'd pull in 30mm diameter conduit if it was mine. I'd lay it as deep as possible, ideally in the insulation layer, so there is no way it can be damaged by someone drilling in a mounting screw.
A bit of a diverse load. You have three options: 1. Extend existing ring final and lighting feeds to the island. This means 3 cables so bigger duct needed. 2. Extend existing ring final to island and install an FCU at the island to power the lighting. That’s 2 cables. 3. Run a new 32amp radial in 4mm cable from CU to island. That’s only one cable, and you could get ghat in 25mm conduit. That’s a new circuit, so ask your electrician.
As suggested by Roger, run a conduit, but as you will have no bending tools, run a flexible, as big as you can get, fit a draw string and plug the ends with paper or similar to prevent concrete or other debris entering the tube.
If in any doubt about whether all the cable will fit in one conduit, installing more than one conduit won’t cost much more. In theory you could use 6491X conduit cable (which is much easier to work with) in the conduit, but then you would need JBs at either end of the conduit to convert to other types of cable.
To be honest, you might be better with something like 50mm waste pipe with a “slow bend” on each end, from the island to the units along the wall. That way it would be easy to add / replace cables as necessary in the future.
I'm with robert, run x2 25mm pvc conduits, buy a bending spring (few pounds) and bend them up out of the trench at the ends or use fabricated smooth bends, solvent weld any joins in the floor. terminate these into adaptable boxes both ends with female adapters, then you can draw through either twin and earth or 6491X as is best suited.
That would work too especially for T&E , again best to go for solvent welded bends so there are no internal ridges to speak of to get in the way
Another method I have seen used, in a commercial kitchen I work in fro time to time is to bury a length of 2"x2" steel trunking with its lid on, and an opening either end (formed by the lid being cut back and a block of wood shoved in prior to concrete), does form a nice easy raceway to poke cables down, they side along easily and the opening is big enough to put your hand in and grab them the other end.
Might even get away with 40mm - that would be adequate for a 6mm to power an oven & hob along with 2x2.5 for sockets on a ring. As you say, "slow bend" not knuckle or elbow as the tight ones are known, using solvent weld. Run a couple of draw string through. There were at one time a couple of posters here who would say - "cannot use waste pipe as conduit, does not meet regs!"
With the talk of pull string, and using the idea of more than one conduit, I would install more than one pull string in each conduit. Obviously something that does not break easily. Maybe also leave a pull string in just in case for any future requirements, for minimal disruption.
Pick a unit on the island and a wall base unit and lay 4 x 25mm plastic conduits in the screed, 20ish mm gap between them to maintain screed strength. Should be as straight as possible, but curved is ok, but no bends. At the units finish with a temporary 300ish square of insulation. Install units cut 300ish square access panels and remove temp square of insulation. You now have clear access and an easy pull, have done similar many times for reception desks etc
Bazza in post #3 shows possibilities with possible feeds. You can buy 3m of 50mm solvent plastic and the necessary glue & fittings for about £30. Or you can go for a few smaller diameter plastic tubes. All installed below the min. of 100mm concrete. Dry fit and elec test needed before any pouring. Assuming no UFH? And FFL has been taken into consideration? I've watched almost as many arguments about feeding Islands as installing Island down vents. I dont think there is a best practice way?
Not read all the replies but whatever you do put the cables in at the same time. Worst nightmare if you cant feed them through afterwards.
Done it (poles, drops & pillar boxings) - but many customers dont like poles or drops of any kind in my experience. The idea of the island work top is for it to be clear and free from obstructions for family sit-downs etc. Nowadays, very few now want sinks or plumbing inserted in the free space. I asked my question to see what post #16 would come up with - the question is still open?