POWERHEAT TYPE AHT TERMINATION INSTRUCTIONS. Ref TK/AHT Issue C Date 16 August 1999

Transcription

1 STOCKPORT, ENGLAND, TEL: POWERHEAT TYPE AHT TERMINATION INSTRUCTIONS PLEASE READ THE INSTRUCTIONS BEFORE PROCEEDING Recommended Tools ANNEX B Ref TK/AHT Issue C Date 16 August 1999 Heavy Duty Craft Knife, Long-Nosed Pliers, Side Cutters, Adjustable Spanner, Rule/Tape, Tissue/Rag, Scissors & Abrasive Paper. Termination Instructions These instructions cover the termination of Powerheat type AHT heating tapes at both supply and remote ends. POWER END TERMINATION 1. Place the gland components on the cable as shown in Fig 1 and slide back along heater whilst cable end is prepared for termination. Fig 1 2. Take the length of heater supplied and check for the start of the heated circuit. This will be marked on the heater by the factory. Check the circuit zone length (node), which will be marked on the cable label. From this information, assess how many heated zones will be needed for the application in hand. Check that there is at least 250mm from the end of the cable to the start of the first heated circuit then, measure the required number of heating circuits and cut the cable 150mm beyond the last required heated circuit, first marking the position of the next node on the remaining cable for future reference (Figs 2a, 2b, 2c). Fig 2a HTL95-TKAHT-009 Page 1

2 Fig 2b Fig 2c 3. When the length of cable to be used has been removed, take the supply end of the cable (the end having 250mm to the first connection) and using a heavy duty craft knife, mark the aluminium sheath as illustrated. Then, using a pair of long nosed pliers lift at point A, carefully stripping back the aluminium sheath 100mm by tearing along the marked lines (Fig. 3). NB - Take care - the inner core must not be damaged in the process. Fig 3 HTL95-TKAHT-009 Page 2

3 4. Strip the top glass braid and mica wrap layers back 100mm from the end of the tape to expose the spiral wound heating element, then carefully remove the exposed heating element (Fig. 4). Fig 4 5. Carefully cut through the glass braid and mica wrap holding the two insulated conductors together - taking care not to damage the individual insulation on each conductor (Fig. 5). Fig 5 HTL95-TKAHT-009 Page 3

4 6. Ensure that any loose end of the exposed heating element is removed; cut-off the tails on the Power Tube Boot; apply RTV to the area and fit the Power Tube boot as shown in (Fig. 6). Fig 6 7. Pass the cable end through the junction box entry, trim the conductors to suit entry into the terminal block, (leaving at least 15mm of exposed aluminium sheath inside the junction box). Remove 10mm of the individual insulation from the end of each conductor, to expose the wires for termination. Then screw the bare conductors into the terminal blocks provided. Screw the gland body into the box and tighten the gland locknut to complete the installation of the cable entry gland (Fig. 7). Fig 7 HTL95-TKAHT-009 Page 4

5 8. Clean surface oxidation from aluminium sheath between power seal and box wall, with knife or abrasive paper. Securely fasten the P-Clip around the exposed aluminium sheath, and to the earth flex with the nut and screw provided, making a good electrical connection. Apply a small amount of RTV to moisture proof the joint, then trim earth flex to suit, remove 10mm of green/yellow insulation to expose wire for termination. Finally, fit the earth flex into the terminal block (Fig. 8). Fig 8 9. Ensure that the cable is in good contact with the surface to be heated as soon as possible after it leaves the gland, and in all cases, before the first node is reached. Apply all the heating cable to be installed taking care to ensure good contact with the surface to be heated until the remote end is approached. HTL95-TKAHT-009 Page 5

6 REMOTE END TERMINATION 10. At the remote end of the cable, strip the aluminium sheath back by 20mm. Strip the outer insulating layers of glass braid and mica wrap back by 15mm and remove all exposed spiral wound heating element wire. Ensure no loose wire ends are present. Then remove 5mm of the cover from one of the insulated conductors (Fig. 9). Fig Apply silicone rubber adhesive to all the exposed heater area, the first 10mm of the aluminium sheath and the inside of the silicone rubber end cap. Then apply the end cap (Fig. 10) Fig IF THE HEATER IS TO BE RUN OVER 200 O C, THE NON-HEATING END OF THE TAPE MUST BE LIFTED OFF THE PIPE AND INSULATED FROM THE PIPE TEMPERATURE USING GLASS FABRIC OR OTHER HEAT RESISTANT PACKING MATERIAL. ALTERNATIVELY, A LONGER COLD LEAD-IN MAY BE FORMED (SEE POWER END TERMINATION ) AND BROUGHT INTO A JUNCTION BOX. 13. Any excess heated length that cannot be fitted, e.g. on small diameter impulse lines, must be cleared through the thermal insulation layer(s) and allowed to radiate to free air. Appropriate measures for personnel protection and warnings of exposed hot surfaces must be provided on site. The information given herein, including drawings, illustrations and schematics (which are intended for illustration purposes only), is believed to be reliable. However, Heat Trace Ltd makes no warranties as to it's accuracy or completeness and disclaims any liability in connection with it's use. Users of Heat Trace Ltd products should make their own evaluation to determine the suitability of each such product for specific applications. In no way will Heat Trace Ltd be liable for any damages arising out of the misuse, resale or use of the product.