Electrically Heated Sidewalks
Installations and Services for:  snow melting systems, heated walkways, driveway heaters, concrete snow melt, roof ice melt systems.
 ask us about it:      Heated Sidewalks - Costs, sizes, types & applications.

Electrically Heated Sidewalks by Able Group Inc.




Wiring connections:
When the surface is cured, connections to the controls and power supply can be completed according to the mat wiring plan. Warning: All lead wires of all mats contain identification labels when shipped from the factory. This identification must be maintained within all connection boxes to ensure ease of identification of individual mats at any time in the future. The mat wiring plan and mat layout plan must be maintained for future reference.

Apply warning labels "CAUTION - ELECTRIC SNOW AND ICE MELTING" to power supply and adjacent to the heated surface. Surfaces should be inspected annually for cracks, exposed cable, etc., and sealed as required with suitable cement or asphalt-compatible material. Should grass or weeds develop in the gaps between pavers, care must be taken when using tools to remove them or the mat may be damaged.

Fixed outdoor electric deicing and snow melting equipment

Equipment for outdoor electric deicing and snow melting should be indentified as being suitable for:
1) the chemical, thermal, and physical environment and
2) installation in accordance with the manufacturer's drawings and instructions.

Electric heating equipment should be installed in such a way as to be protected from physical damage. External surfaces of outdoor electric deicing and snow melting equipment that operate at temperatures exceeding 140 degrees Fahrenheit should be physically guarded, isolated, or thermally insulated to protect against contact by people in the area. The presence of outdoor electric deicing and snow melting equipment should be evident by the posting or appropriate caution signs or markings where clearly visible.

Resistance Heating Elements
Panels or units should not exceed 120 watts per square feet of heated area. The spacing between adjacent cable runs is dependent upon the rating of the cable and should be no less than 1 inch on centers.  

Units, panels, or cables should be installed as follows:
1) On a substantial asphalt or masonry base at least 2 inches thick and have at least 1 1/2 inch of asphalt or masonry applied over the units, panels, or cables; or
2) They should be permitted to be installed over other approved bases and embedded within 3 1/2 inches of masonry or asphalt but not less than 1 1/2 inch from the top surface; or
3) Equipment that has been listed for other forms of installation should be installed only in the manner for which it has been identified.

Cables, units, and panels should be secured in place by frames or spreaders or other approved means while the masonry or asphalt finish is applied. Cables, units, and panels should not be installed where they bridge expansion joints unless provision is made for expansion and contraction. Heating element assemblies should be secured to the surface being heated by approved means. Where the heating element is not in direct contact with the surface being heated, the design of the heater assembly should be such that its temperature limitations should not be exceeded. Heating elements and assemblies should not be installed where they bridge expansion joints unless provision is made for expansion and contraction. Where installed on flexible structures, the heating elements and assemblies should have a flexural capability that is compatible with the structure.

Non-heating leads having a grounding sheath or braid should be permitted to be embedded in the masonry or asphalt in the same manner as the heating cable without additional physical protection. All but 1 inch to 6 inches of non-heating leads not having a grounding sheath should be enclosed in a rigid metal conduit, electrical metallic tubing, intermediate metal conduit, or other raceways within asphalt or masonry. The distance from the factory splice to raceway should not be less than 1 inch or more than 6 inches. Insulating bushings should be used in the asphalt or masonry where leads enter conduit or tubing. Leads should be protected in expansion joints and where they emerge from masonry or asphalt by rigid conduit, electrical metallic tubing, intermediate metal conduit, other raceways, or other approved means. Not less than 6 inches of free non-heating lead should be within the junction box. Power supply non-heating leads (cold leads) for resistance elements should be identified for the temperature encountered.

The in-ground sensor is encased within a rugged enclosure and is intended to be embedded within the surface being heated, usually concrete or asphalt. The moisture sensor is supplied with a protective field cover to simplify asphalt or concrete installations, and comes with 30' of wire for connection back to the heater sensor control unit. The sensor has an integral 1/2" NPT conduit connection. The moisture sensor connection wire may be extended up to 500' with an appropriately rated 18-20AWG 4 wire shielded cable.

The low voltage moisture sensor senses falling or drifting snow by melting it on the "grid" area of the sensor and then detecting the presence of moisture by measuring an electrical signal between the grid bars. The moisture sensor also measures the temperature of the surface. This "dual sensing" technique allows the heater sensor to control the heating equipment (mats, cables, etc.) in the optimum manner possible. This assures minimum energy costs while still providing reliable surface snow detection.

Snow melting systems are designed to melt snow and ice in outdoor locations, such as driveways, parking ramps, sidewalks, steps, etc. The mats are expected to be completely embedded in asphalt or concrete surfaces. Snow melting systems can be installed under pavers. The intended installations are residential walks, patios, and driveways. The mats contain an electrical heating element designed to provide a fixed amount of heat. When connected to appropriate system voltage, and when a system control detects the presence of ice or snow, the mats are energized. Then, heat from the mats increases the surface temperature of the pavement to above freezing, melting snow or ice on the surface. When controlled by the controls, the mats provide economical and reliable snow and ice melting performance.

These mats are embedded in conjunction with the paving installation. Some control and accessory devices may also require installation at this same time. The mats are comprised of a single length of heating cable formed into a rectangular shape (except custom mats can be almost any shape) and secured in this shape by polymer carrier strands fused to the cable. Cold leads are factory connected to the mat and are available in various lengths to suit the location of electrical connection boxes. The mats are available in both standard and custom sizes (length, width, power, voltage, etc.). Thermal insulation is not required beneath these mats, but will improve the performance and operating cost efficiency of the installation by reducing back losses. Consult with architect/engineer to ensure structural integrity of any thermal insulation.

Each installation must have a mat layout plan and mat wiring plan prior to beginning the installation. This information will ensure that all necessary mats are available at the site prior to paving, and that all mats correspond to the installation requirements (shape, power supply voltage, etc.).

The mat layout plan must clearly identify the following:
- location and tag number of each mat
- routing of cold leads for each mat
- location of all junction boxes
- routing of all conduit
- location of all controls/sensors
- location of all drains, pipes, and similar obstructions
- pavement type
- expansion and control joints
- areas which may be drilled in the future for fastening of surface mounted structures, such as hand railings, signs, bollards, parking bumpers, etc.

The mat wiring plan must clearly identify the following:
- connection details of heat mats, controls/sensors and power supply
- identification of each mat, control/sensor, junction box, etc.
- branch circuit ratings

The mat layout must be designed to cover the area to be protected, and allowance must be made for obstructions, such as light poles, expansion joints, control joints, etc. In some cases such obstructions can be accommodated by modifying mat shape.

Mats must be laid in accordance with the mat layout plan to which they were manufactured: this plan must be available at the job site. Identify location for expansion and control joints. Concrete forms may be inaccurate, so allow 2-4" on each side of the mats for clearance. Allow approximately 4 inches between adjacent mats at expansion and control joints. For asphalt, mats must be placed at least 12" in from edges to accommodate variations in edging. Adjacent mats may be positioned within 2", but must not touch or overlap. Mats must not be placed under areas to be drilled in the future for fastening of surface mounted structures, such as hand railings.

Control joints are typically indentations in a concrete surface along which cracks are intended to form. The indentations may be formed by special trowel prior to hardening of the concrete, or by cutting with a special concrete saw after concrete has set. Cracking at control points and subsequent movement of adjacent sections could damage a mat crossing a control joint; therefore, mats must not be intentionally positioned through control joints. In case of unintentional shifting of mats during pour, control joints must not be sawn closer than one inch above mats to ensure that mat heater cable is not damaged by the saw.

Expansion joints are, typically, formal separations between sections of concrete, with some flexible material forming the separation which then absorbs any thermal expansion in the concrete section. Movement of adjacent sections could damage a mat crossing an expansion joint, hence, mats must not be positioned through expansion joints.

Appropriate wiring of all mats must be completed according to the mat wiring plan. Conduit must be used to protect the non-heating leads at the exit from the installation area to the junction boxes. All necessary conduit and other wiring devices to be installed within the surface must be available prior to beginning mat/surface installation. In most cases the ideal location for junction boxes is indoors with at least 18" of accessible mat leads within the box. When planning the location of the junction boxes it is important that at least one foot of mat cold lead remains embedded in the asphalt or pavement. Junction boxes and conduit should be located so that they can accommodate the maximum number of mat leads expected to be routed to/through them. Insulating bushing must be used to protect the cold lead where it enters conduit.

Controls/wiring must be installed according to the mat wiring plan and mat layout plan. (Some controls include devices required to be installed in the heated surface). All wiring must conform to Local and National Electrical Codes. If the mats are controlled simply by manual electrical switches, it is recommended that a pilot lamp be installed on the load side of each switch so that there is a visual indication when the mats are energized.

The pavement must be installed in accordance with proper construction practices, including allowance for drainage, reinforcement, etc. Improper pavement installations can result in unstable surfaces which can crack/move and break mat heating cables; warranty is void in such situations. Concrete installations must not contain aggregate greater than .75".

The distance from the finished surface to the level at which the mats are placed is defined as the "mat placement depth". The mat placement depth must not be greater than 3 1/2" (to ensure adequate surface heating) nor less than 1 1/2" to ensure complete containment of the mats within the surface covering. Typically, a base layer of concrete is poured and leveled, then the mats are immediately positioned, and then the remaining concrete is poured. It is also possible to allow the base layer of concrete to set, then position the mats and complete the pour. If the second pour is inordinately delayed, a binder or binding agent should be employed to minimize shear plane formation. Asphalt installation must not contain aggregate larger than 3/8" and must be delivered to the job site at a temperature less than 340 degrees Fahrenheit - larger aggregate and/or higher temperatures will damage cable and result in failure. Typically, a base layer of asphalt is laid and allowed to set, then the mats are positioned, and then the final layer of asphalt is laid. (It is also possible to lay mats on an existing layer of asphalt that is being resurfaced). The mats must be located between 3 1/2" and 1 1/2" of the finished surface to ensure adequate surface heating.

Extreme care must be used when machinery such as wheelbarrows, rollers, front-end loaders, tractors, paving machines, etc. is involved in the installation of heating cables/mats in asphalt or concrete surfaces. Such machinery must not have cleats of any type nor metal tracking of any type, as such cleats/tracking can sink into the asphalt and contact the mat, possibly damaging the cable. The use of sharp implements, such as rakes, shovels, etc., is usually required during surface installations. However, unless care is taken, these can damage mats during installation. All workers must be advised to avoid contacting the mats with such implements, and that, if they do, the mat must be immediately checked for damage.

Do not route wheelbarrows, rollers, trucks, etc. over uncovered mats. It is recommended that workers not walk on the mats. When mats are installed on rebar or in other situations where weight on the mats would be highly concentrated, damage to the cable is possible that would result in immediate or later operational failure. Local electrical inspectors may require inspection prior to, during and/or after surface installation. Be certain that they are contacted prior to beginning mat installation.

Electrical panels and controls must be identified as to their snow melting function. Snow melting areas must be identified by clearly visible signs or marking. Pavement identification nameplates are available. Do not use admixtures or chemical compounds that may be harmful to copper or PVC. Snow melting units are approved for use in wet locations. The heater-to-cold-lead wire splices made at the factory are designed and tested to be waterproof. To ensure a completely waterproof installation, it is also important that all field connections must be waterproof. The use of approved exterior type junction boxes, fittings and bushings plus care in waterproofing splices will assure a reliable and trouble-free electric performance. It is required that all products listed by UL and CSA be properly indentified. Therefore, if the leads on these mats are shortened, ensure that a minimum 6" of cold lead with the identification tag is retained within the junction box.

Mats may be tailored to follow contours of curves and other obstructions by making a series of cuts to the mat carrier strands. Extreme care should be exercised to prevent cutting the mat heater wire during this operation. 

Start all cuts on the side opposite the cold lead and cut strands towards the cold lead side. To make a curve, cut strands. The number of strand cuts will depend on the mat length and surface curvature. In the same way, mat shape can be altered to form a wider block pattern or to go around an object. To ensure adequate heating, do not allow cable spacing at outer edge of curve to be more than 2 times the standard cable spacing.

Site/Mat Preparation:
Excavate and compact surface area and, if applicable, install appropriate thermal insulation. Complete surface area preparation. Lay mats in position according to the mat layout plan. Install all wiring, conduit and control devices associated with the surface installation and according to the mat layout plan and mat wiring plan. Do not connect power supply at this time. Conduits must extend into surface to ensure no wiring is exposed. Position all control/sensors to be installed within the surface and connect all wiring/conduit. If necessary, provide appropriate protection for these devices during surface installation.

The continuity and insulation resistance of each mat must be tested prior to paving. Record readings. Connect a megger between the copper grounding braid and the inner conductor on one lead of a mat. Ensure the other lead of the mat is isolated and that the heating element is not in contact with the ground braid. Set the megger at 500 V (minimum) and measure the resistance. The resistance must be 10 Megohms minimum. This test assures that the mat has not been damaged during shipment or subsequent handling. Next connect an ohmmeter between the inner conductors of the two leads of the mat. Measure the resistance of the mat. Be certain that the mat resistance is appropriate for the marked wattage and voltage. Repeat above test for each mat used in the installation. Position all mats associated with the surface installation according to the mat layout plan and mat wiring plan. Thread mat cold lead wires through conduit into associated junction box. Lay mats in position to check original layout and spacing. Leave sufficient slack in lead wires to permit handling of mats. Lay mats aside temporarily to allow for installation of base layer of surface material. If necessary, provide protection for any controls which may get damaged or dislocated during pour.

Installation in concrete:
Pour concrete to mat placement depth. Distribute concrete such that top surface is roughly level. Reposition mats, in accordance with the mat layout plan, with all lead wires secured within the concrete and maintaining appropriate clearances to edges of forms and between adjacent mats. Reposition all controls as required. Complete the pavement pour and level. Retest mats according to initial testing.

Installation in asphalt:
Pour and roll the base layer. If mats are to be placed on an existing surface, make sure the surface is clean and free from any sharp material that could puncture mat heating cable during installation. If necessary, apply a coat of bituminous binder to the base layer. Reposition each mat according to the mat layout plan, allowing clearance to edges and between adjacent mats. If necessary, apply a coat of binder over each mat. Reposition all controls as required. It is advisable to cover the entire mat in one continuous layer. Note: Do not dump large quantities of hot asphalt on the mats. The temperature at the base of the pile may damage heater wire. Maximum asphalt temperature is 340 degrees Fahrenheit; higher temperature will damage the cable and result in failure. Once asphalt has cooled to below 100 degrees Fahrenheit, again check the mats according to initial testing to be sure no damage has occurred during installation.

Installation in concrete steps:
Pour concrete to within 2 inches of finished step surface and roughly level. Position mat section for first step according to the mat layout plan, and ensure any excess cold lead wire is secured within the concrete. Allow 2" clearance to front edge of step. Ensure cable in riser portion of step is embedded in concrete. Mat cable may not touch forms. Complete the surface pour and level. Retest mats according to initial testing.

Installation under pavers:
Carefully follow the paver manufacturer's instructions and the guidelines of the Interlocking Concrete Pavement Institute, Tech Spec Number 12,
for installing electric snow melting mats under pavers. Do not install a mat within the compacted aggregate base, as this may damage the mat and result in mat failure and will void the warranty. Do not install a mat in a concrete base under pavers, as this may not provide sufficient heat or may result in a much longer time to melt any snow or ice. It is highly recommended that an experienced paver contractor do the paver installation in coordination with an electrical contractor for the mat installation. Paver design and installation varies with local climate, materials, soil conditions including drainage, and expected use loads.

Proper preparation of the soil and aggregate base and the use of edge restraints to prevent loss of sand are critical. Loss of sand may result in mat failure. Secure the mat to a wire fabric with nylon cable ties attached to the WHITE MAT STRANDS ONLY wherever possible. If ties must be used on the black heating cable, leave slightly loose, DO NOT fully tighten or the tie may cut into the cable and result in failure of mat in operation. Lay the mats on top of either the compacted aggregate base (patio/walkway type installation) or the concrete base (driveway type installation) and cover with sand. The mat heating cable and splice to the non-heating leads must be fully contained in the sand bed. Retest mats according to initial testing.