Underfloor heating in Kitchen

[GasmanH]

SWMBO wants to change the current carpet tiles in our Kitchen.

One of the options includes electric underfloor heating.

If we proceed then I am aware of Part P and LHBA notification requirements that meen I must pre notify if DIY or use an accredited electrician.

What I want is confirmation - or otherwise of the alternatives.

THere are currently two rings and a cooker radial feeding the Kitchen

Cooker is electric double oven and Gas hob pluged into Cooker outlet. (RCD protected)

Ring One supplies Dishwasher, Washing Machine (both Cold Feed), Tumble dryer and several sockets.

Ring Two supplies Fridge, separate Freezer Kettle and Several sockets (RCBO protected).

As I understand, it there is insufficient capacity in any of the circuits to add the heating system (currently estimated at 1050W, but max 1500W) except possibly the Ring Two but not enthusiastic about this as the risk to Fridge/freezer contents if fault occurs when unattended.

This means - I think - new circuit from CU. There are spare ways on the non RCD side - so would need RCBO. THe only way to get cable from CU to kitchen is to go outside. This would seem to need SWA - unless normal Twin/E in black plastic conduit (such as this http://www.tlc-direct.co.uk/Products/MT20HGB.html) is acceptable.

If this is correct then SWMBO may well loose interest in this option.

Many thanks

 

[SparkyNinja]

Is ring 1 RCD/RCBO protected?
A max load if 1500w (approx 6.5A) shouldn't be a problem loaded onto a fcu supplied from one of your existing rings.

 

[electronicsuk]

I can understand your reluctancy to connect the UFH to the same circuit that feeds the fridge/freezer. I don't think you should discount your washer/dryer/dishwasher ring completely - do you ever really run all of those at once? Before even considering diversity, the capacity of the ring would still allow you to run TWO appliances drawing a full 13A and still have 1380w left over (assuming 32A protective device) to feed your heating, assuming the ring is evenly loaded. In reality, you would probably be able to run all three appliances plus the UFH at the same time without problems.

 

[GasmanH]

In answer:-

Wylex split load CU



Ring 1 and Cooker are on the Protected side of RCD. Ring 1 32 MCB Cooker 40 MCB

It is possible that all three could be on at once - but not starting and the other sockets are usually used for general food preparation except for one that has 850w (output) microwave - but this is infrequently used.

 

[SparkyNinja]

The maximum demand on a circuit like this would still accomodate another 6.5A

Put it on a fcu from the ring. I would normally use the ring that doesn't have the kettle on it, but you may not drink as much tea as me

 

[Taylortwocities]

You must have avery big kitchen. Are you sure about your 1050W figure?

 

[GasmanH]

Kitchen is almost 4m X 4m. Central "walking" are about 7m2, although exact layout may be a little more or less

From Screwfix (http://www.screwfix.com/prods/35760/Heating-Cooling/Electric-U-floor-Heating/Klima-Underfloor-Heating-150W-7sq-m) or (http://www.screwfix.com/prods/43187/Heating-Cooling/Electric-U-floor-Heating/Klima-Underfloor-Heating-Mat-150W-5-sq-m) give ratings of 750W to 1050W. Not researched elsewhere yet to see if these values are typical.

It seems sensible though to work to worst case ie 1050W.

Another thought though - current Ring 2 RCBO is 30mA trip (and32 Amp over current). Does anyone do a 10mA RCD to site appliance side of a FCU - and would this provide sufficient discrimination to prevent the RCBO tripping? And without the heating mat leakage current tripping it?

 

[ban-all-sheds]

SWMBO wants to change the current carpet tiles in our Kitchen.

I don't blame her - carpet in a kitchen?

One of the options includes electric underfloor heating.

Why not a wet system?

If this is correct then SWMBO may well loose interest in this option.

Is that what you'd prefer?

 

[GasmanH]

SWMBO wants to change the current carpet tiles in our Kitchen.

I don't blame her - carpet in a kitchen?

One of the options includes electric underfloor heating.

Why not a wet system?

If this is correct then SWMBO may well loose interest in this option.

Is that what you'd prefer?

Flotex has been good, but its 10 years old and showing it - difficult to de dog hair!!

Although there is a radiator in there I am told (by BG) that the piping is only just big enough for the current load. AND form what I can see it will very significantly raise the floor.

Theres only 2cm between the white goods top and underside of worktop so thta would mean raising the worktops - great fun!!

Not sure - but it would be nice to have a warm floor at 6 am when I get up for the dogs and work!

 

[huw169]

I was going to do this and have now changed my mind.
Spoke to a few people who say that it's not all that good and a few others who have had a nightmare trying to get it to work.
It is also expensive to run - info from a few electrician mates who could have sold me a system - they advised against it.

Have you thought about a plinth heater plumbed into your existing radiator system? This is the option i have chosen after lots of considerations about ufh (actually underfloor 'warming')

That said, i am insulating under all my floors to reduce the 'heat draw' from the floor void in winter, and have opted for a wood floor in the kitchen to reduce the 'the bear foot freeze of tiles'.

Not trying to put you off cos if that's what you want - excellent. Just giving you my findings after a bit of research.
Good luck