Best cable type for in floor heating

[Avulstein]

I am planning on redoing my basement floors and debating on adding underfloor radiant heat. It would be supplemental to my HVAC as the basement as being 70 year old house all registers are roof mount.

My question is due to the large area of main room roughly 13' × 30' (4m × 10m) 400 square feet or 40 square meters. This leads to my current problem, most single cables are less than 100m (300') or harder to find, (I've only found a single 1000' cable which is what I'd need to do the entire room). What seems to be an easier solution would be to run 10 parallel runs of heating cable. Using 33ohm/m cable that would roughly be 10 × 110Watt circuits. Which of these would be the better option. The single cables systems seem to all run around 3000-4000 Watts.

Is there any disadvantage to running the parallel circuits rather than the single cable system?

 

[Dan]

Single cable electric underfloor heating systems are thinner and easier to repair (specialists work in this area, usually the tile industry as that is who would traditionally install it). Double are thicker and can go up to 200W/m2 and are the more common.

We would run the cables to a junction box and that to the thermostatic controller and that to a switched fused spur but often the load would require its own feed as they are power hungry heat source. Lovely to walk on.

Just wondering what prices compare as www.uheat.co.uk are forum sponsors and offer discounts to members.

 

[Avulstein]

Single cable electric underfloor heating systems are thinner and easier to repair (specialists work in this area, usually the tile industry as that is who would traditionally install it). Double are thicker and can go up to 200W/m2 and are the more common.

We would run the cables to a junction box and that to the thermostatic controller and that to a switched fused spur but often the load would require its own feed as they are power hungry heat source. Lovely to walk on.

Just wondering what prices compare as www.uheat.co.uk are forum sponsors and offer discounts to members.

I've taken a look at that site, it looks fairly similar in price regarding matts and coverage after a rough currency conversion, that way (which would still need several to be run in parallel). In Canada there isn't much in terms of truly Canadian suppliers, most hardware stores supply still comes from America.

I would still be having the branch wiring done by electrician as it has to be done and inspected that way to be legal here (I've assumed similar there). I'm not so worried about depth for install (was thinking would probably end up with at least 2-3cm increase off concrete once all said and done). The hope was to have everything installed when new floor placed either a laminate or tile. Then have an electrician come and wire up the breakers, thermostats etc. And since it was going to be supplemental I hadn't thought about going to that high of wattage.

 

[Dan]

The wire can't go under laminate. And on top of concrete you need insulation boards (just xpf boards can go as thin as 6mm over here).

Otherwise you'll never get the slab warm enough to store heat.

Under laminate heating is more of a foil 0.5m wide roll and you have loads of them to fill a floor and they give small amount of heat and it isn't very good to be honest.

Then there's "ribbon under-laminate heating" which is similar (search aht ribbon heating) but also terrible under wood or laminate.

So if you want the effect to work right your layers would be tile adhesive to stick the insulation down, insulation (6mm - 50mm the more the better), cable (or mat), self levelling compound, tile adhesive then tile.

So work backwards once you have your tile chosen and squeeze as much insulation as you can.