Devi Heating Systems - In Screed Installations

	To achieve even spacing the cables are attached to a wire netting or light gauge reinforcing mesh. Cable spacing shall be as even as practical across the entire heated area, with reference to the required surface loading and maximum cable loading. Cables should be laid so as to avoid water pipes, baths, built-ins etc, where it is known that permanent structures are to be installed above the finished floor, or where the floor is likely to be penetrated by nails or similar fixings, (the yellow lines indicate the boundaries of permanent fixtures).
	The whole assembly may rest on the base of a clean concrete slab or existing tiled floor, free from sharp objects, and be covered with sufficient screed to ensure the cable is a minimum of 25mm from the underside of the finished surface unless designed for less. Cables should be no closer than 100mm from any wall or fixed item.
	The entire length of evenly spaced heating cable, including the cold tail termination, must be embeded in sand/cement screed, unless designed for other applications. As an alternative to the wire netting, the cables are attached to Devifast™ fixing strips which are, in turn, nailed to the existing concrete floor. The fixing strips allow for accurate, easy to manage cable spacings.
Deviflex™ Cold Tails (black cable ends)	Where contactors are required, the cold tails should terminate in a wall/control box approximately 300mm above floor level. If the thermostats supplied are capable of switching the load direct, the cold tails could be taken directly to the thermostat position. The conduit containing the floor sensor should, naturally, also terminate at this control box. It is important to establish where the control box will be situated before installation to ensure that cables are laid out correctly.

The sensor conduit, sealed to prevent sand/cement or water from damaging the probe, is generally installed between cable loops.
	For a Freezer or Subfloor Installation (pictured left) it is common practice to install two circuits. The primary heater circuit should be connected to the supply and the other used as a back up system or spare. Twin circuits should NOT be run together using the same fixings. Rather they should be run at midway spacings, side by side (pictured left) or at right angles.
	To avoid accidental damage, the cables should be covered as soon as possible with the screed/topping.