INSTALLATION GUIDE

Read these instruction sheets carefully to familiarise yourself with the full product rangeand appropriate methods of installation

General

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TRACE HEATING SYSTEMSCross Trace Heating will compensate for heat losses from thepipework or vessels in order to maintain or heat up to therequired process temperature.

This Installation Guide provides detailed instructions forinstalling Trace Heating Equipment manufactured andsupplied by Cross Electrical (Nottingham) Ltd.

For technical assistance and advice on the design or selection ofheating cables, for all applications relevant to appropriatestandards - Give CROSS a call!

All Cross products and services are supported by personnel whoare well trained in the design and application of Trace HeatingSystems. Cross Electrical will engineer and submit detailed designspecifications with all enquiries received.

ASSURANCE OF QUALITYCross Electrical (Nottingham) Ltd is an ISO9001 RegisteredCompany and all Cross Trace Heating equipment is designed,manufactured and installed against BS6351 Parts 1,2 &3.

DESIGN POLICYCross Electrical (Nottingham) Ltd will ensure you are providedwith the correct design for your application otherwise it couldmean:

• Removal of Thermal Insulation• Removal of Electrical Trace Heating• Purchase and fit of a new Trace Heating system• Refit of Thermal insulation

Long Heating Units are supplied incable reels.

INSTALLATION GUIDE

Cross Heating Cables

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CROSS ELECTRICAL RANGE

Cross have 10 standard types of heatingcables which are easy to install andmaintain.

All the cable types (except XPZ) can bedesigned for use with any voltage from6 volts to 440 volts.

Cross Heating Cables Units are normallysupplied at a defined length/fixed heatoutput - fully terminated ready forinstallation and connection.

XINC Medium to long lengthheating circuitsFor use in VERY hightemperature applications upto 10000C

XSSMedium to long lengthheating circuitsFor use in high temperatureapplications up to 6000C

XCN Medium to long lengthheating circuitsFor use in high temperatureapplications up to 2500C

XHP Short to medium lengthheating circuitsFor hazardous andnon-hazardous applicationsup to 2300C

XSWE Medium to long lengthheating circuitsFor hazardous andnon-hazardous applicationsup to 2300C

Short Heating Units are supplied in200mm or 600mm diameter coils

INSTALLATION GUIDE

Cross Heating Cables

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XRHFor roads & ramps, includingasphalt applications. Preventionof snow and ice build-up.

XFHBFor underfloor heating,footpaths, patio installationsOUTSIDE

XFH For underfloor comfort heatingapplications INDOORS

XSSTC Short to medium lengthheating circuitsHeavy Duty - For use in hightemperature applications upto 6000C

XPZ Parallel. Cut to any lengthFor frost protection incommercial or industrialapplications up to 500C

NOTABLE ATTRIBUTES OFFIXED RESISTANCE CABLES

Temperature controlled fixedresistance trace heating provides anefficient economical solution fornumerous process applications.

The cables can provide anengineered trace heating system forintermittent or continuousoperation.

When secured in intimate contactwith the pipe and thermallyinsulated, they will compensate forheat loss from the pipe to maintainor heat it up to the desiredtemperature.

Heat output is uniform and constantalong the complete length of thecable.

Power output can be checked at anytime regardless of ambient orprocess temperature.

Potential faults created bymechanical damage can be easilylocated for local repair.

INSTALLATION OF HEATING CABLES

The method of installation detailed below assumes that the thermostat or junction box is located at one end of the pipeline and that a double run is being applied.

Refer to element schedule and select the appropriate heatingunit.

The recommended method of installing Cross heating cables is to straight trace on the pipework in single or multiple runs.

Working away from the thermostat or junction box, carefully unroll the heating cable along the route of the pipeline.

For installation into standard XP5 or XP6 or XPEC thermostatsallow 400 mm of cable from base of Pipe Mounting Brackets (PMB).

Minimum bending radius is equal to seven times the outside diameter of the cable.

On horizontal pipework the cables should be secured to the underside of the pipe at 4 and 8 o’clock positions.

On vertical pipework the cable should be applied on oppositesides.

Securement/fixings should not be more than 200mm spacings.

Heating cables should be applied to pipework, valves and fittings so that the cable is in direct contact with the equipment being trace heated

INSTALLATION GUIDE

Installation Principles

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ASSURANCE OF SAFETYPersonnel involved in the installation of ‘Cross’ trace heating systems should be competent electricians suitably informed in the specified technique required

Installers are not normally expected to design circuits. Before ordering or installing, a detailed design should be undertaken and specified by Cross Electrical.

Series resistance heating cable should not be altered or shortenedwithout consulation with Cross Electrical (Nottingham) Ltd.

PRE-INSTALLATION

Ensure that the pipework and all other items forming each circuit are complete in all respects.

Ensure all systems, pipes and tanks have been pressure tested prior to the installation of the heating cable.

Ensure that all pipelines are adequately earthed.

Valve handles may require extension spindles to accommodate specified thickness of insulation.

Check that the pipeline is free from any sharp edges, weld splatter or cement splashes.

Refer to heating cable schedules, layout drawings and design documents to identify the location of the heating circuits and control thermostats/junction boxes.

Check that the trace heating has been designed to operate at the voltages specified in the ‘Heating Cable Schedules’. The installer should check that these supplies are correct and available.

Ensure that the heating cable to be installed is suitable for any corrosive substances that may be present.

Separate temperature controlled circuits should be provided on dead end legs and closed by-passes.

Pumps and small vessels should be trace heated and controlled independently. The circuit on the pump should be physically separate to permit disconnection during maintenance or removal.

Do not install heating cable on pipes or equipment which could have a higher process temperature than the maximum withstand temperature of the heating cable.

Installing Engineer should ensure that the pipelines for which non approved heating units have been provided DO NOT crossboundaries into any areas classified as hazardous.

Check that correctly rated RCD protection is being provided.

To ensure that the heating cable is run out straight,always unroll from cable drum or coil.

Do Not coil off as this will cause a spring effect and create problems for installation.

UNREELING CABLE

Installing engineer should not pull cable over sharp edges.

Installing engineer should not use force if a cable snags whilebeing pulled in.

Installing engineer should not allow cable to be walked on or subjected to other abuse which could cause mechanical damage.

INSTALLATION OF MINERAL INSULATED HEATINGCABLES XSSTC - XSS - XINC - XCN

Stainless Steel Tie Wire is to be used for securement and fitment of MI heating cables.

Commencing at the thermostat / junction box, carefully unroll the heating cable along the route of the pipeline.

Bend the cold lead-in cable at 900 to the pipeline and run upthe PMB stem to the thermostat / junction box, disposing of any spare cold lead-in cable by forming a loop or coil.

Enter the tails of the cold lead-in cables into the thermostat /junction box for termination after installation.

Screw the cable gland body into the thermostat / junction box and tighten screw gland nut onto the gland body. Slide the PVC shroud into the position over the gland. Carry out this operation for each of the cold lead-in cables so that theypresent a neat and tidy appearance.

Working away from the thermostat or junction box, apply the heating cable to the underside of the pipeline as described above and secure in position by means of the stainless steel tie wire at 100mm intervals.

Any spare heating cable should not be applied in the vicinity of a control thermostat bulb, as this will cause the thermostat to give an incorrect control temperature reading.

No heating cable should be allowed to cross over or come into contact with each other.

INSTALLATION GUIDE

Installation Principles

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MAINTENANCE

Circuits controlled by ambient air sensing thermostats should be fully tested pre-winter considering time may be required to carry out repair / remedial works.

Circuits on process pipework and vessels should be fully tested at least once a year.

The following tests and checks are recommended to be made at six monthly intervals and whenever any work is carried out on the pipeline, or equipment to which the trace heating cables are attached.

Test the electrical supply cable for continuity, insulation resistance and conductivity of the earth path.

Examine the RCD/MCB feeding the system for any signs of overloading or distress.

Test the RCD is in operation using a calibrated instrument.

Test the heating units for continuity (ohms).

Test the heating units for insulation resistance between heating element and earth braid / outer sheath.

Record the results of these tests and make a comparison with the test results documented at the commissioning stage.

Check the operation of the temperature control thermostat and re-commission the system.

Visually examine the pipeline system for any physical damage, considering that damaged thermal insulation could conceal a damaged trace heating cable.

Arrange for any damaged or missing thermal insulation to bereplaced and sealed.

SECUREMENT/FIXINGS

Cross heating cables are to be secured to pipework by means of specified fixing tape or pre-punched fixing band.

Secure heating cable with fixing tape at 500mm intervals to the underside of the pipe at a 4 O’clock position.

Unroll the cable back to the start point and secure with fixingtape at 150mm centres at an 8 O’clock position.

Pipework up to 150mm Nb the heating cables can be further secured to the pipe wall by spiralling fixing tape around the pipe and cables to give a secure continuous fixing at 200mm spacing.

On long pipe runs, pull cable firmly and temporarily fix the cables every metre with a single band of fixing tape along thepipe length, working the cable back to start position. Fixing tape to then be spiralled around the pipe and cable to give a secure continuous fixing at 200mm spacing.

Spare heating cable should NOT be applied in the vicinity of acontrol thermostat bulb or temperature sensor, as this will cause the thermostat to give an incorrect control temperature reading.

Spare heating cable should, if possible, be applied to flanges,fittings and valves.

DOCUMENTATION & LIFETIME RECORDS

Operation Maintenance Manuals (O&M) and documentationrecords are produced in Electronic ‘Autocad’ format.

INSTALLATION GUIDE

Positioning and Fixing

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Cable Fixing Positions

On horizontal pipework, the cables should be secured to the underside of the pipe at 4 & 8 o’clock positions.

On vertical pipework, the cable should always be applied on opposite sides.

Expansion JointsConsider movement of expansion joint and leave slack incables.

SECUREMENTS AND FIXINGSPipework

Stainless Steel Tie Wire

Glass Cloth Fixing Tapes

ADDITIONAL INSTALLATION RECOMMENDATIONS

Pipe SupportsIt may be necessary to allow for and apply additional heatingcable on certain pipe supports.

Recommended installation method for surplus cable

INSTALLATION GUIDE

Pipework Installation - Do’s and Don’ts

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Flanges Provide a suitable loop when crossing over flanges and in-linefittings - secure cables either side of flange.

Pipework,Bends & Elbows Always apply heating cable to the outside (long) radius ofpipe bend/elbow.

Cable RunsDo Not overlap cables. heating cables must not be allowed tocross or come into contact with each other.

Valves Form a sufficient loop of heating cable into an ‘S’configuration on each side of the valve and secure with fixingsspecified.

Allow a minimum of 50mm spacing between runs of cable.

Do not spiral heating cables around the pipework.

Do not spiral heating cables around pumps, valves andsimilar items of equipment, as this restricts removal of the equipment.

INSTALLATION GUIDE

Installation Methods for Process Equipment

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VesselsInstall fixing band around the body at regular spacings to secureheating cables or use pre-fabricated heating grids to supportcable.

Pumps, Filters and Irregular FittingsLight gauge stainless steel mesh can be formed to the shape of thepump,filter or fitting. The heating cable can then be formed andsecured onto the mesh using high temperature tie wraps or tie wire.

SECUREMENTS AND FIXINGSProcess Equipment

Hopper Heating Grids, Flat Surfaces or Tank BasesCut weldmesh panels to the size and shape of surface to be heated.Form the heating cable on to the mesh and secure using hightemperature tie wraps or tie wire to give an even distribution ofapplied heat. The heating grid can then be secured firmly to the flatsurface or tank base by means of stud welded pins, purpose madebrackets or heavy duty fixing band.

Stainless Steel Fixing Band

Stainless Steel Mesh

Stainless Steel Tie Wire

Pre-punched Fixing Band

Heating Grids can also be fitted or immersed INSIDEtanks and vessels

INSTALLATION GUIDE

Thermostats

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CONTROL OF TEMPERATURE

All trace heating circuits should have temperature control.

Cross XP5 & XP6 Mechanical Capillary Tube and Bulb thermostatsare the most economical and commonly used method oftemperature control and come fitted with ‘supply healthy’ and‘heating on’ indication.

XPEC Electronic Controllers are used for monitoring and closecontrol of process temperatures and incorporate a‘serial communications’ facility to enable remote monitoring,data logging and adjustment of operating temperatures.

LOCATION OF CONTROL THERMOSTATS ANDJUNCTION BOXES

Identify the proposed thermostat or junction box location andconsider practical accessibility for future maintenance purposes.

XP5, XP6 and XPEC surface sensing temperature controls shouldbe mounted in an accessible location where practical and shouldnot be subjected to excessive shock or vibration.

Temperature sensing bulbs & probes should be located on top ofthe pipe, away from the heating cable, firmly secured to ensuregood contact.

Ensure no spare heating cable is applied in the vicinity of acontrol thermostat bulb or temperature sensor, as this will causethe thermostat to give an incorrect pipeline temperature reading.

Ambient air sensing thermostats should be installed at a locationwhere the lowest ambient temperature is expected.

Junction Boxes should be mounted in an accessible locationwhere practical and should not be subjected to excessive shockor vibration.

XP5/SA Single Pole

XP5/SAA Ambient Sensing

XP6/SA With Ammeter

XP6/SC With high temperature lock-off

XP6/TA Three pole/ 3 phase switching

INSTALLATION GUIDE

Thermostats

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ORDINARY ENVIRONMENTS AND LOCATIONS

Pipe Mounting Brackets for Thermostats andJunction Boxes

Cross pipe mounting brackets are designed to provide a simplemethod of mounting thermostats and junction boxes ontopipework. They also serve as an exit or entry through Thermalinsulation and outer cladding for heating cables and thermostatcapillaries.

Standard stainless steel pipe mounting brackets (PMB) comprisea 25mm x 25mm angle saddle with a flat bar stem supporting amounting plate.

The brackets, combined with a flexible conduit sleeve, provide aprotective entry / exit through the thermal insulation and outercladding for standard heating cable installations

Installation of Thermostats with Capillary Tube andSensing BulbTo secure the pipe mounting bracket (PMB) to the pipe, sit theangle saddle on the surface of the pipe and secure with jubileetype clips or stainless steel banding.

Mounting plates are pre-drilled for fixing of junction boxes orthermostats and come supplied with fixing screws.

Secure the thermostat enclosure on the mounting plate of thePMB with the screws provided.

Determine the location of the sensing bulb. At least 200mmalong from the PMB support.

Unroll sufficient capillary tube or sensor lead from the coil toreach the location and dress neatly to follow the route of theheating cable down the protective spacer bar. Continue thecapillary tube onto the pipeline, locating the sensing bulb on topof the pipe and secure with fixing tape.

Leave spare capillary tube or lead in coil at side of thermostat.

N.B. When installing temperature sensors, especially thermostatbulbs and capillaries, care should be taken to avoid distortion orcrimping which would impair calibration.

Termination of XHP, XSW, XSWE into Thermostatsand Junction BoxesThread the heating cable through the flexible conduit and leavetails for termination after installation and testing.

Gland each flexible conduit into Thermostat or junction Box.

Form flexible conduits down stem of pipe mounting bracket andsecure with tie wraps.

Do not connect until all initial tests before and after ThermalInsulation are completed.

THERMAL INSULATION

Thermal insulation is an important aspect of every trace heatingapplication.

Type and thickness of thermal insulation specified on designschedules must be used.

Correct temperature maintenance requires properly installed anddry thermal insulation; please consider 2% dampness in mineralwool will double heat losses.

Valve handles may require extension spindles to accommodatespecified thickness of insulation.

Ensure that all points where valve stems, support and pipemounting brackets exit the cladding are suitably sealed to keepwater out.

Ensure that the trace heating does not get damaged duringinstallation of metal cladding by drills, self-tapping screws orsharp edges of metal cladding.

To minimise heating cable damage, install thermal insulation assoon as possible after tracing

BEFORE APPLYING THERMAL INSULATION

Visually inspect the heating cables and temperature controls forsigns of mechanical damage. If damage is found or observed,either replace the complete heating cable or cut out thedamaged section and replace using the proper throughconnection repair joint.

Test the heating units for insulation resistance (500 volt Megger)between heating conductor and earth braid / outer sheath.Document, date and witness all test results.

Any cable with an insulation resistance of less than 500megohms should be investigated further.

Before applying thermal insulation test the heating units for con-tinuity (ohms) and verify against identification label circuit ohms.Document, date and witness all test results.

Arrange for the thermal insulation to be applied as soon aspossible after trace heating cable has been installed. This willprotect the cable from possible damage.

Over-size Thermal Insulation may be required to compensate forthe size of the Trace heating cables, particularly if large diametercables are specified on small diameter pipework. The thermalinsulation should be applied in such a manner that no gapsoccur between longitudinal or butt joints.

Heating cables should be in direct contact with surface to beheated and never get embedded within the thermal insulation.

AFTER FITMENT OF THERMAL INSULATION

After the thermal insulation is applied, again test the insulationresistance of the heating unit (500 volt Megger) and continuityto ensure that no damage was caused to the heating cables.Document, date and witness all test results.

Any cable with an insulation resistance of less than 500megohms should be investigated further.

When the thermal insulation is finally completed ‘Caution TraceHeating’ labels should be applied on the outside of cladding atintervals of 3 metres maximum.

Cross Electrical (Nottingham) Ltd. in-houseThermal Insulation Division provides acomplete turnkey package

Trace Heating and Thermal Insulation in Corrosive Environment

Thermal Insulation on Process Pipework/Equipment

INSTALLATION GUIDE

Thermal Insulation

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