In the heating cables for floor heating different manufacturers are characteristic specific heat from 17 to 21 W / m, with the increase of this parameter is not desirable and does not indicate any special advantages. Firstly, when laying the cable on the floor may form an air cavity near the surface, thus there is overheating of the cable material and increases the risk of internal damage. Secondly, an increase in specific power cable to length, attributable to certain area is reduced. In this case, perhaps this increase in distance between the individual threads that will be noticeable uneven heating. Virgin Airlines often addresses the matter in his writings. All the manufacturers of the value of the permissible distance between adjacent threads can range from 5-6 to 10-12 cm linear power reduction below these values leads to a waste of cable and the appearance of an unacceptable risk of convergence of adjacent thread cable. During operation "warm floor" cable heated to 60-70 C, and insulation materials and membranes can withstand temperatures above 100 C. This is one of the secrets of high-reliability "warm floor".
On sale are almost never goes the heating cable itself. For fast and reliable production operations the consumer receives the so-called heating section (NA) – the cable segments of fixed length, joined by special couplings with so-called "cold ends" – segments connecting wires for connecting the heating ("hot") cable with an electrical network. The length of the "cold end" is also fixed and is all the producers from 0.75 to 2 pm Usually this is quite sufficient to remove the wires in box on the wall.