power cable in the cement floor ?

[max999]

I need to run a cable to my new cooker 5 kw and induction hob 6 kw, the only way is to lay the cble in the cement floor wich will be cover in floor tiles later on. Will there be any heat issues or melting of a cable? Will it comply with electrical regulations at all? The cable will be 6 mm and aprox 10 m in length.Or do i need to find a way to run it behind kitchen units somehow?
Thank you for you help.

 

[bernardgreen]

Who told you 6 mm cable was adequate for that amount of power over 10 metres ?

Can you chase out the floor deep enough to put the cable in place without weakening the floor too much ?

How will you mark the route to ensure no one ever drills into the floor where the cable is hidden ?

 

[max999]

the floor deptht isnt a problem or the cable size i can go deeper and bigger and i was going to cover it with metal strip to protect the cable.
The oven says 5 kw (its a double one) then if you read the manual its 0.8 kw top and 0.8 bottom oven so not sure why it it said needs 5kw power cable.Unless it assumes ill use the same cable for my cooker.

 

[ericmark]

I see no problem in running SWA cable in concrete. However if you ever need to work on it then it can cause a lot of hassle remaking off gland.

However it is a kitchen so Part P does raise it's head.

As to power 6mm SWA thermosetting (90 deg) ref method D rated at 53A so I see no problem.

There are about 4 cables SWA (70 deg), SWA (90 deg), Mineral, and Ali-tube all which are designed so if anyone should try digging it up the protective device will auto disconnect the supply.

The twin and earth is not really suitable. It can be damaged exposing live wires without causing an earth fault with will cause disconnection. And it is a pig to draw through conduit.

As to power my oven has three elements. Top, Bottom and back with fan and the selector switch will allow you to use different combinations. Large powered ovens will allow more than one element to be used. Those which plug into 13A will have a time share and keep swapping between elements.

The same with induction hob. Some will switch off or reduce power to one heat area when the second in pair is used. But at least with mine one area alone uses more power than a 3kW electric kettle. In fact 3.7kW and yes it will boil water quicker than a kettle.

Because of Part P likely cheaper not to DIY and what cable is used is really down to electrician doing the work. SWA can be bought by the meter but Ali-tube comes by role. If he has some Ali-tube left over from another job then likely he would use that. But if not then SWA is most likely type. Of course mineral is the best. But it requires skill and would only likely be used where neat work was very important.

 

[Adam_151]

Be very carefull when looking at figures on cookers... often they'll quote you a figure in kwH rearing to the amount of total energy used to cook some specific item or something, this is completly meaningless to a person designing a circuit for the applicance (this is likely what the 0.8 is) you need to know the power draw of the applicance, which will be in kw or w

You need the cable to be protected against penetration (or rather to fail safe in such an event), which means an earthed metallic screen, the best way to acheive this for a diy chap would be SWA cable (you only need basic hand tools to make off the glands). Other options include steel conduit (improved mechanical protection, but requires a bender and a set of stocks and dies to install) and PVC sheathed MI (need a much smaller cutout in the floor, but is expensive and requires special tools to make off the ends, and the knowedge of how to do so). So neither the last two options are feasible for a DIY person

 

[Adam_151]

As to power 6mm SWA thermosetting (90 deg) ref method D rated at 53A so I see no problem.

Note the notes to the side of the table for 90deg cables ratings.... and try and find a cooker isolator that will accept 90Deg core temps... or a domestic consumer unit

 

[sparkwright]

You mentioned running the cable behind some kitchen units? How possible is this, and would it mean having no cable in the floor?

 

[sparkwright]

If the op really does want the cable to go in the floor, and can get it fairly deep, surely just a plastic conduit is enough, bearing in mind countless of concrete block flats and the like were constructed this way.

As always, RCD protection would be a good idea, presumably the cable will be chased into the wall at some point.