Installation Guide

20 INSTALLATION
Heating Cables Installation
Warning Details
• Before installing and operating this product, the user and/or installer must read, understand and follow these instructions and keep them handy for future reference.
If you have a question, please contact Customer Service by phone [phone] (USA) or 800-667-8746 (Canada) or from our website at www.schluter.com.
• If these instructions are not followed, the warranty will be considered null and void and the manufacturer deems no further responsibility for this product.
• The following instructions must be adhered to in order to avoid personal injuries or property damages, including serious injuries and potentially fatal electric
shocks or fire.
• This product must be installed by a qualified person in accordance with this installation handbook and with the Canadian Electric Code Part I (Canada) or the
National Electric Code (U.S.) as applicable. All electric connections must be made by a qualified person, according to the electrical and building codes effective
in your region.
• De-energize all power circuits before installation and servicing.
• A dedicated circuit is recommended for each application, but a circuit supplying one or more fixed room heaters may be used, as long as its rating does not exceed 30 amperes,
that the total current from all branch circuits does not exceed 80% of the circuit breaker limit, and the branch circuit cable reaching the thermostat junction box is of the same
conductor size as the main circuit.
• A Class A (5 mA) ground fault circuit interrupter (GFCI) is required for each circuit. The DITRA-HEAT-E thermostats include a GFCI, thus a GFCI circuit breaker is not required when
using these thermostats.
• NEVER install a cable designed for a 120 V power source on a 240/208 V power source.
• The heating cable ground braid must be bonded to ground.
• For installations requiring a cold lead trim or splice, the electrical rating label shall be fixed to the cold lead and visible at the termination junction box. Removing the label will void
the warranty.
• Never CUT or modify the heating cable in any way. This would change the cable resistance, will cause damage to the cable, and could cause cable overheating.
• The type and thickness of floor covering materials used with this product must not exceed a thermal insulation “R” value of 1. Example “R” Values: Ceramic/Mosaic tile 0.25"
thick = R0.15, Natural stone 1" thick = R0.38-0.114, Porcelain Tile 0.25" thick = R0.024. Vinyl/LVT/LVP/WPC/SPC 0.25" thick = R0.4, Engineered Wood (glued) 0.5" thick = R0.25,
Engineered Wood (floating) 0.5" thick + 1/8" padding = R0.5, Laminate Flooring 0.38" thick + 1/8" padding = R0.62
• Heating cables shall not be altered in the field. If the installer or the user modifies the unit, he will be held responsible for any damage resulting from this modification, and the
warranty and the product certification will be void.
• Heating cables may not touch, cross over, or overlap one another or itself.
• The heating section of the cable and the factory splice (i.e., black plastic junction between the cold lead and gray heating cable) must be entirely installed under the floor covering,
and into a mortar or thin-set layer, as shown in the heating cable installation instructions. Do not install it in a wall, or anywhere else, as this may cause overheating and system failure.
• Threading the cold lead from the floor to the thermostat junction box needs to be done within an approved raceway or conduit. The conduit is required to begin at no greater than
2 inches (50 mm) from the floor. The opening in the horizontal stud at the base of the wall, which provides access for the cold lead to the inside of the wall, shall be covered by a
steel plate to protect the cold lead from any possible future damages from nails or screws.
• The temperature sensors need to be threaded either inside the same conduit as the cold lead, or in a separate conduit.
• Do not run the heating section of the heating cable set under or through a wall, partition, or through a floor.
• Do not install the heating cable on a wall (e.g., shower wall, inside of a built-in bathtub, etc.).
• In the USA, according to Rule 424.38 (A) of the National Electrical Code 2017, heating cables may extend beyond the room in which they originate. In previous editions of the
National Electrical Code (NEC), extending heating cables beyond the room was not permitted. Please verify with your local inspector to determine which edition of the NEC is being
enforced by the local Authority Having Jurisdiction (AHJ). Also, please verify approval of your cable layout prior to setting tile. Additionally, installations of heating cables in dressing
rooms or large walk-in closets are subject to approval by the local AHJ.
• In Canada, according to Rule 62-202 of the Canadian Electrical Code 2018, a thermostat or an applicable temperature control device is required for each enclosed area where a
heating cable is installed. As necessary, please verify your installation plan with local inspector to determine their interpretation of the rule, and whether or not your cable layout
is approved prior to setting tile.
• NEVER install the heating cable under vanities with no air space beneath, bathtub platforms, free standing bathtubs with no air space beneath, kitchen cabinets and islands,
appliances, or any other fixtures, or in small storage or clothing closets where there is or could have various items on the floor. Excessive heat will build up in these confined spaces
and may cause cable overheating.
• NEVER use the heating cable for any purpose other than for indoor floor warming as explained in this Handbook.
• Cable spacing shall be limited to a repeating 3 stud (3.6" or 9.1 cm) spacing, or a continuously alternating 3 stud (3.6" or 9.1 cm) and 2 stud (2.4" or 6.1 cm) spacing (i.e.: 3-2-
3-2-3-2 and so on) between cable runs. A repeating 2 stud spacing or narrower spacing shall not be used as it may cause overheating and cable malfunction. A wider spacing
(e.g., 4 studs) may not provide sufficient power to warm the floor to the desired temperature, and may cause inconsistent floor surface temperatures. Exception: a continuous 2
stud spacing is recommended when connecting a 240 V heating cable to a 208 V power supply. See page 33 for more information.
• Minimum spacing from walls, partitions, and fixed cabinets is 2" (50 mm).
• Minimum spacing from other heat sources (baseboard heaters and other fixed heating devices, fireplaces, etc.) is 8" (200 mm).
• Minimum spacing from any forced air heating vents is 4" (100 mm).
• Minimum spacing from the centerline of toilet drain is 7" (180 mm).
• The minimum spacing from any drain pipe must be 4" (100 mm). With a linear drain, the cable must be 4" (100 mm) from the actual drain pipe and a minimum of 1" (25 mm) from
the channel body edges.
• The maximum allowable straight length of a single run of heating cable is 10 ft (3 m); the cable must be turned and go in the other direction, or form u-shaped "jog" at this point
as in Photo 5b on page 22. This is to take into account the expansion of the metallic hot conductors of the heating cable while heating.
• The minimum temperature at which the cable should be installed is 32° F (0° C).
• Avoid folding the heating cable on itself, a radius of curvature less than 1/16 inch (1.6 mm) could damage its sheath.
• The minimum installed bending radius of the heating cable is 0.5 inches (12.7 mm).
• NEVER energize the cable while it is on the spool. This would lead to overheating that could damage the cable.
Heating Cables Installation
• DITRA-HEAT is primarily intended to warm tile floors and make them more comfortable underfoot, but can contribute to space heating. See page 34 for space heating guidelines.
• It is helpful to plan the location of a buffer zone, as it is not possible to predict where the heating cable will end. The buffer zone is an area where heating is not essential and heating
cable installation is not planned (e.g., behind a toilet or adjacent to a door opening). This area allows for placement of excess heating cable. Heating cables may also be installed
6" (150 mm) from the wall to create a buffer zone.
• Mark the circuit breaker in the electrical panel that is connected to the DITRA-HEAT floor warming system using the identification sticker provided. Additional stickers provided may
be placed on the electrical panel door.
• Install the two thermostat floor temperature sensors within the tile assembly. Two floor temperature sensors are provided - one with the DITRA-HEAT thermostats and one with
the DITRA-HEAT-E-HK heating cables. Install the tip of each temperature sensor in the middle of the three stud spacing cable runs, no matter if the standard 3 stud cable spacing
or the continuously alternating 3-2 stud cable spacing option has been used. Connect only one to the thermostat and the other is a spare in case one is broken during overall
installation. The floor temperature sensors need to be threaded either inside the same conduit as the cold lead, or in a separate conduit.
• Heating cable testing is required while the heating cable is on the spool and at two subsequent steps during installation to ensure cable quality and for warranty purposes.
• If a break or damage is detected during the heating cable testing while the heating cable is on the spool, return the cable to the original place of purchase. Do not proceed with
heating cable installation into the DITRA-HEAT or DITRA-HEAT-DUO matting or with the tile covering installation.