Specification for Design & Installation of Snow Melting System
Following are general requirements for the design and installation of the BRITECH snow and ice melting system.
The electrical contractor shall supply and install a complete snow and ice melting system which shall consist of the following:
1. Electric heating cables.
2. Temperature controllers and auxiliary sensors.
3. Accessory materials such as contactors, pre-punched strapping, junction boxes, etc.
4. Heating panel and feeders.
The extent of the snow and ice melting system is as shown on specification sheets and architectural drawings.
The entire design and installation of the system shall comply with the Electrical Code (current edition) and the requirements of the “Authority Having Jurisdiction”.
Products / Materials
1. Heating Cables
Heating cable manufactured by Nexans consists of a series resistance heating wire, insulated by a crosslinked polyethylene, covered with a metallic sheathing and an outer PVC jacket. Each cable includes a multi-stranded copper ground conductor running the full length of the cable. Type UF lead wire, length as required, shall be factory crimped to the cable. Cable shall be CSA & UL listed and meet the latest NEC regulations when properly installed.
The cable is a single conductor, series resistance cable designed specifically for the application. The cable shall have the ability to be in contact with metallic mesh or wire in accordance with NEC regulations. Manufacturer’s instructions shall be followed.
To ensure maximum snow melting rate, heat output shall not decrease as the temperature of the slab increases. Heating cables that modulate their thermal output and cannot be checked for circuit integrity, or are characterized by high inrush currents at start-up are not acceptable.
Heating cables will be designed for operation on one supply voltage up to 600V.
All heating circuits shall be controlled by one or more of the following methods:
1. A high limit slab sensing thermostat and / or timer.
2. An automatic snow / ice sensor (preferred) that detects precipitation occurring at temperatures below 38 ° F (4° C).
3. Where the rating of the controller would be exceeded, it shall be used in conjunction with a relay or contactor.
1. Cable sheaths shall not touch one another nor shall cables cross expansion joints. Special procedures are required for crossing control and construction joints.
2. Heating cables are laid out at the specific spacing. Spacing should not be greater than 6 inches to ensure reasonably uniform distribution of heat.
3. All junction boxes shall be located in accessible areas. Junction boxes shall not be located in the heated slab, but shall be located above grade level. Covers shall be kept on boxes at all times when not working therein.
4. All terminations shall be protected from the weather and from physical damage and bonded to the system ground.
5. Any field alterations or deviations shall proceed only after the engineer has issued authorization. All changes shall be accurately recorded by the contractor and shall be turned over to the engineer upon completion of that phase of the work.
6. Field testing of insulation resistance and continuity of the units shall be carried out with a 500 Volt insulation tester and recorded by the electrical contractor. Testing shall be done when received on the job site, during installation, and after installation by the Electrical Contractor.
7. Insulation resistance shall be consistently not less than 5 megohms.
8. Conduct a complete system test of the controls to verify cable operation.
9. Copies of all such testing shall be delivered to the Engineer.