Direct acting heating requiring 60-100 W/m2 (5.5 - 9 W/sqft):
These systems require low thermal capacity and the heating cables are placed as near to the floor surface as permitted by local and national authorities. Normally this means that the heating cable is placed in the lower part of a max. 50mm (2") thick screed on a high grade thermal insulation.
When renovating, or when space is essential, special thin screed solutions are used, allowing screed thickness down to 10-15mm (3/8" - 5/8").
By using the factory made heating cable units -all with 17 W/m (5.2 W/ft) -the calculation of center spacing is simplified.
Use the following formula to determine the length of cable you will need:
open square footage x 12 ÷ length of cable. (O x 12 ÷ L )
Example:50 ft2 X 12 ÷ 96ft (cable TXLP/1 500/17) = 6in on center

Type
Load at 230 V (Watt) Element-length (*) [ft] Outer diameter [mm] Weight per unit [lb]
TXLP/1   300/17 300 58 6.5 2.9
TXLP/1   400/17 400 75 6.5 3.5
TXLP/1   500/17 500 96 6.5 4.2
TXLP/1   600/17 600 115 6.5 5
TXLP/1   700/17 700 135 6.5 5.5
TXLP/1   850/17 850 164 6.5 6.8
TXLP/1   1000/17 1000 193 6.5 7.7
TXLP/1   1250/17 1250 241 6.5 9.2
TXLP/1   1400/17 1400 270 6.5 10.1
TXLP/1   1750/17 1750 338 6.5 12.7
TXLP/1   2200/17 2200 424 6.5 15.8