Ⅲ、Attention on Installing Parallel Electric Heat-Tracing Bend with Constant Power:
　　１.Preparations for Installation：
　　（1）Understand the design on electric heat-tracing bend while learning the specification of the using electric tracing bend and the number of all the accessories and auxiliary materials.。
　　（2）Understand the design on electric heat-tracing bend while learning the specification of the using electric tracing bend and the number of all the accessories and auxiliary materials.
　　（3）Analysis on Current Situation: Implement analysis on the overhead construction, bury, flammable subjects, temperature and moisture, and the difficulty in operation. After analysis and judgment, the collaborative heat preservation is used and all the staffs get ready for the work and relevant coordination work.
　　（4）Analysis on Current Situation: Implement analysis on the overhead construction, bury, flammable subjects, temperature and moisture, and the difficulty in operation. After analysis and judgment, the collaborative heat preservation is used and all the staffs get ready for the work and relevant coordination work.
　　２.Preparation for Construction:
　　（1）Check out if the electric heating bend is good and if the type, meter power and voltage are in line with the design requirements.
　　（2）Check out if the design proposal is in line with the delivered equipments including accessories.
　　（3）Determine the location of the point of electric supply, as well as the location of the end of electric heating bend; Determine the laid length and laying method of the electric heating bend.
　　（4）Determine the location of paying-off reel of the electric heating bend and the paying-off method. But don’t harm the electric heating bend while paying off.
　　（5）The method for laying electric heating bend varies as single laying, double laying, multiple laying, Z reeling and spiral winding, etc. The length in spiral winding can be determined by simple evaluation. The total winding length is approximately 3 times the length of pipeline if the interval of spiral winding is equal to the pipe diameter.
　　（6）To start the laying of electric tracing bend, the surface of the pipe should be cleared without any oil stain, obtuse angle, sticky matter. Besides, the protecting lacquer should be dried.
　　３.Construction of Electric Heating Bend
　　（1）Installation of electric heat-tracing bend should be implemented after the installation of pipeline and line sweeping.
　　（2）The electric heat-tracing bend is generally laid 45 degrees laterally below the pipeline.
　　（3）When constructing, it is necessary to fix the electric heating bend on the pipeline with heat-resistant belt at the interval of 0.6m.
　　（4）Then cover the laying electric heating bend with aluminum belt and make the electric heat-tracing bend adjacent to the pipe or equipments to increase the efficiency of heat tracing.
　　（5）The installation of electric heat-tracing bend should consider the accessories of pipe and the possibility of removing and maintaining equipments. Besides, there should be margin for repair. If there is a valve, the electric heating bend can be circled (or bifilarly winded) around the valve. It is convenient for removing if it needs repairing. It desterilizes after repair.
　　（6）The electric heat-tracing bend is not allowed intercrossing and overlapping to avoid excessive heat. Otherwise, the normal life of electric heat-tracing bend will be affected.
　　（7）When installing the end, it needs the attention on the core wire. The thermal fuse cannot touch or collide with braid. Otherwise, it will cause short circuit.
　　（8）When the length is installed less than 5m, it needs the attention on the processing of cold side. If there is fine pipe, it is necessary to protect the electric bend from being damaged by excessive heat.
　　（9）It is required to be reliable and water-proof to install connecting wire for the accessories of electric heating bend, temperature controller, junction box, temperature controller box, etc.
　　（10）The temperature controller can only be installed horizontally and vertically downwards. And the installation of connecting wire should be correct and reliable. The temperature should be adjusted to the one that could maintain the media. The temperature sensor should be parallel to the electric heat-tracing bend with interval of about 1~2 cm. Specifically, in occasions where the voltage of power source is too high or too low and where the temperature is too high, it needs more attention on the placement of temperature measurement head.
　　（11）In the moist zone, the inner part of wire-connecting box should be filled with waterproofing glue while the wire-connecting port in explosion-resistant zone should be with more explosion-resistant resin mortar.
　　（12）Except the reliable ground protection installed in the media pipe system of electric heat-tracing system, the braid of electric heat-tracing bend should be reliably ground connected. (the ground resistance should be less than 4Ω).
　　４.Debugging and Running
　　（1）It must be tested strictly and singly when installation is complete, application megohm table to check the electrical insulation resistance between wire and earth should be on less than 2MΩ. And then check up if DC resistance of circuit with design wattage of cable. Check the unqualified, the cause shall be investigated and ascertained in good time, and the case shall be properly handled.
　　（2）Before power is supplied again, to check the insulation resistance of heating cable, measure its current, and make a record.
　　（3）After that, begin to construct thermal insulation and protection layer. Then repeat to check electric heating system and switch on for 24hours. Inspection at any time if necessary in time to deal with unusual circumstances.
　　（4）It should post warning label in the pipeline external coating to be reminded of the danger.
　　（5）In addition to the above installation, fitting and running adjustment of heating cable shall comply with relevant provisions of applicable national Code for Design of Electric Equipments in Explosion and Fire Hazard Environments. Construction and acceptance of electrical equipments in explosion and fire hazard environments, besides provisions hereof, shall also comply with provisions of applicable national standards or codes.
　　（6）The protective device accomplished function of overload, short-circuits, breaks and leakage. So as to effectively from a balanced three-phase system.
　　５.Finishing:
　　（1）After installing the heating cables, the worker should clean up the job site.
　　（2）ensure installation quality and fulfill relative record and keep in the archives for the future reference.
　　（3）perform regular audit of temperature controller to in form the all users.
　　Ⅳ、The Notices During Installation:
　　refer to the relevant point of installation of parallel connection electric heating cable. Also note that the unique aspects of series connection electric heating cable.
　　（1）the series connection electric heating cable type will be designed based on the each pipeline. So, series connection electric heating cable in the use of attention when choosing the right type, the models can not be mixed up.
　　（2）one pipeline for one type (special exceptions)。
　　（3）Actual install length agree with designed length. Such as long or short arise be informed designer, and deal with respectively.
　　（4）2-way junction box only correctly working and sealing with water-proof glue, but suitable length should be left for the connection later (2 meters per box).
　　（5）Make testing for insulation resistance and measure value for cable still install ending.
　　（6）Series connection electric heating cable shall wear casing when cross the highway and don't damaged the heating cable.
　　（7）Underground pipeline and insulation work have been installed, please guard against damage when put the pipeline into a ditch.
　　（8）The pipeline direction, relative position, and management of special condition must be serious and responsible work. Keep recording for reference.
　　Special instructions: make sure the heating cable not be damaged during installation. Making thermal insulation to ensure the warming quality (thermal insulation bottom construction quality.)