Nelson Installation and Maintenance Manual: GA-2090, Constant-Wattage Cable Manuals & Guides
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Installation &
Maintenance
TYPE NC
CONSTANT WATTAGE HEATER CABLE
Page 2
CONTENTS
GENERAL INFORMATION.................................................................................................................4
How Heating Systems Work................................................................................................................4
PRODUCT SELECTION.......................................................................................................................4
PRINCIPLES OF OPERATION ............................................................................................................4
RECEIPT & STORAGE.........................................................................................................................4
Receipt.................................................................................................................................................4
Storage................................................................................................................................................5
Withdrawal from Storage....................................................................................................................5
INSTALLATION ...................................................................................................................................5
Scheduling...........................................................................................................................................5
Pre-Installation Check........................................................................................................................5
Heater Handling .................................................................................................................................5
Heater Cable Location ........................................................................................................................6
Straight Tracing..................................................................................................................................6
Spiraling..............................................................................................................................................6
Attachment ..........................................................................................................................................7
Cutting the Heater Cable....................................................................................................................7
Installation Details..............................................................................................................................8
SYSTEM COMPONENTS...................................................................................................................10
THERMAL INSULATION..................................................................................................................11
Pre-Installation Checks.....................................................................................................................11
Installation........................................................................................................................................11
Marking.............................................................................................................................................11
THERMOSTATS & SENSORS...........................................................................................................11
ELECTRICAL REQUIREMENTS ......................................................................................................12
Voltage Rating ..................................................................................................................................12
Electrical Loading ............................................................................................................................12
Ground Fault Protection...................................................................................................................12
Waterproofing...................................................................................................................................12
TESTING..............................................................................................................................................13
Recommendations .............................................................................................................................13
Procedure..........................................................................................................................................13
START-UP ...........................................................................................................................................15
Heat-up Time ....................................................................................................................................15
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OPERATION & MAINTENANCE..................................................................................................... 15
System Design, Installation & Documentation.................................................................................15
Preventive Maintenance................................................................................................................... 15
Visual Inspections............................................................................................................................. 15
Frequency.........................................................................................................................................15
Personnel Training...........................................................................................................................15
Maintenance..................................................................................................................................... 16
Piping Repairs..................................................................................................................................16
DAMAGED PRODUCTS....................................................................................................................16
TROUBLESHOOTING....................................................................................................................... 17
POWER TERMINATION INSTALLATION .....................................................................................20
Overjacket Stripping Procedures .....................................................................................................20
Outer Jacket Stripping Procedures ..................................................................................................21
END SEAL INSTALLATION.............................................................................................................22
Overjacket Products......................................................................................................................... 22
Braided Products.............................................................................................................................. 22
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GENERAL INFORMATION
This manual is designed for use with Nelson Heat Tracing Systems type NC constant wattage heater cable. For
applications not specifically addressed, please contact your local representative.
How Heating Systems Work
An electric heating cable system uses the electric heater cable to replace the heat that is lost through the thermal
insulation system. Replacing the lost heat allows the pipe and product inside the pipe to be kept at a constant
temperature. This will keep water from freezing and bursting a pipe, or a liquid from setting up and plugging
the pipe. Simple systems may turn the entire system on with a contactor or switch, while others will use a
thermostat with each heater cable to control the temperature.
Insulation
Heater Cable
Pipe
Figure 1
PRODUCT SELECTION
Check and verify that the proper heater cables are being installed on each pipe and vessel. If no
design/installation documents exist, check Nelson Heat Tracing Systems Design & Selection Guides to
determine the proper equipment for the application.
PRINCIPLES OF OPERATION
The 12-gauge bus wires supply voltage along the entire length of the heater cable. A nichrome resistance wire
(heating element) is spirally wrapped around the bus wires contacting alternate bus wires at specific intervals
forming a heating zone. The point where the resistance wire contacts the bus wire is referred to as a node. This
series of parallel heating zones provides a constant power output for each zone, irrespective of where the cable
is cut along the length of the bus wires. Once the cable is cut you have made that heating zone inoperable.
Heater cable will begin its heating at the first node from the cut. Refer to Figure 11 for proper node location on
a typical heater circuit.
RECEIPT & STORAGE
Receipt
• Compare the materials against the shipping bill to verify receipt of proper materials.
• Inspect heating cable and components for transit damage. Insulation resistance tests on each spool of cable
are recommended.
• If design documents (line lists or per circuit bills of material) exists, check the received materials against the
lists to verify all needed materials are received. If no design documents exists, keep a receipt log of all
materials received.
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GA-2090 Rev. 1
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September 2005
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Storage
Cables and system components should be stored in a clean, dry area. The equipment should be protected from
mechanical damage during storage. The storage temperature range is -40°C to 60°C (-40°F to 140°F).
Withdrawal from Storage
It is recommended that a check out record be kept (in conjunction with the receipt records) on equipment as it is
removed from storage. This will serve to identify developing material shortages before they happen - since
project additions often cause the use of material for other than designated piping.
INSTALLATION
!
WARNINGS:
While there are many acceptable ways of installing Nelson Heat Tracing Systems’ electric heating equipment,
certain actions can be dangerous to personnel and your installations. Please take care to avoid the following
problems:
• Do not twist the bus wires together at either end of the heater cable. Each of these wires has a voltage or neutral
applied to it; twisting them together will cause a short circuit.
• To prevent electrical arcing and fire hazard, all cable connections and electrical wiring connections should be
sealed against moisture. This includes the use of proper cable sealing kits and the moisture proofing of all wire
connections.
• Do not expose heater cables to temperatures above their maximum ratings. Higher temperatures can greatly
shorten the life of a heater cable.
• Immediately replace any damaged heater cable or components. Failure to replace any damaged components
(heater cable, components, or thermal insulation) will result in system failure.
• Classified areas (explosive dust or gases) require the use of special electrical components. Any area having
explosive gases (such as chemical / petrochemical installations) or explosive dusts (such as coal handling or
graineries) require special cable, connection components and control components that are approved for use in
these areas. Installation of non-approved products can result in fires or explosions.
• Installation on plastic pipe is not recommended. See the Nelson Heat Tracing Systems design guide for details in
design and selection.
Scheduling
The installation of the electric heat tracing needs to be coordinated with the piping, insulation, electrical and
instrument groups. It should begin only after the majority of mechanical construction is complete. Pressure
testing of the pipe and installation of the instruments should be complete prior to the start of the heater cable
installation.
Pre-Installation Check
Walk the piping system and plan the routing of the heater cable. Use this check to verify completion of
instrumentation and mechanical work. All coatings (paint, corrosion protection, etc.) must be dry before
installing heater cable on pipe or vessel.
Heater Handling
• Use a reel holder with counter to roll out the heater cable. Accurate records of installed cable footage are
important for both installer and maintenance personnel.
• Route heater cable close to the pipe being traced. This will avoid interference with pipe supports, grating
and other equipment during installation.
• Locate node to insure that a full heating zone is properly located for both end termination and power
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GA-2090 Rev. 1
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September 2005
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termination.
• From the last node leave an extra 305-457mm (12-18”) of heater cable at all power connections, tee splices
and end seal connections to facilitate easy working of the connections.
• ADDITIONAL HEATER CABLE IS REQUIRED ON VALVES, PIPE SUPPORTS AND OTHER
EQUIPMENT. See the installation detail section for exact lengths and method of installation.
• When handling the heater cable, avoid pulling it over or installing against sharp edges.
• Do not kink or crush the cable. Heater cable should not be left in areas that would allow damage by walking
on it or driving over it with equipment.
Heater Cable Location
The heater cable may be installed in either straight runs or spiraled around the pipe. Spiraling is generally used
when a limited number of cable output wattages are available.
Straight Tracing
When straight tracing is used, install the heater cable on the lower quadrant of the pipe. This helps prevent
physical damage to the heater cable from falling objects or from being walked on.
Alternate Locations
120°
Install heater cable at the
4 or 8 o'clock positions
Figure 2
Spiraling
Spiraling increases the length of heater cable installed per foot of pipe. Installed cable length = Pipe Length X
Spiral Factor. The following example and table will allow you to determine the correct pitch for each pipe size
and spiral factor:
Example: When using .43m (1.4ft) of heater cable on102mm (4”)
IPS pipe, the Pitch (P) would be 356mm (14”).
Figure 3
PITCH (P)
in inches
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GA-2090 Rev. 1
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Table I
Spiral Pitch Table (Inches)
Pipe Size (feet of heater cable per foot of pipe)
(IPS) 1.1 1.2 1.3 1.4 1.5
1.0 NR NR NR NR NR
1.5 NR NR NR NR NR
2.0 17 NR NR NR NR
2.5 20 14 NR NR NR
3.0 24 17 13 NR NR
3.5 28 19 15 13 NR
4.0 31 21 17 14 NR
4.5 35 24 19 16 14
5.0 39 26 21 18 15
6.0 46 31 25 21 18
8.0 59 41 33 28 24
SPIRAL FACTOR
1 inch = 25mm
Attachment
For regular installations, the heater cable may be attached with fiberglass tape. Plastic wire ties may also be
used, provided the wire tie material has a maximum temperature rating equal to or better than the system
requirements. The cable should fit snugly against the pipe and be secured at 305mm (12”) intervals, as shown
in Figures 4 & 5.
Fiberglass Tape
Aluminum Foil Tape
(AT-50)
305mm (12")
Figure 4 Figure 5
Note: To prevent possible damage to the heater cable, do not fasten with metal straps or wire.
Cutting the Heater Cable
Do not cut the cable until it is attached to the pipe. Confirm the allowances for terminations, connections, heat
sinks (valves, support, etc.) and node location before cutting the cable. Heater cable power is not affected by
cutting to length. Protect all heater cable ends from moisture or mechanical damage if exposed for long periodsof-time.
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GA-2090 Rev. 1
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Installation Details
Heater cables should be applied in a manner to facilitate the easy removal of valves and small in-line devices
without the removal of excessive thermal insulation or cutting the heater cable. This can be accomplished by
looping the cable at each heat sink, see Figure 6. The amount of heater cable installed on each valve, hanger,
etc. varies with the pipe size and type of device. Table II gives the correct amount of additional cable to be
installed on each device.
Table II
Heat Loss Adder
Pipe Fitting Type
Pipe
Size
.50 .30 1.0 1.0 1.0 1.0
.75 .30 1.0 1.5 1.0 1.5
1.00 .30 1.0 1.5 1.0 2.0
1.50 .30 1.0 2.0 1.5 2.5
2.00 .30 1.0 2.0 2.0 2.5
3.00 .30 1.0 2.0 2.5 3.0
4.00 .50 1.0 2.5 3.0 4.0
6.00 .80 1.0 2.5 3.5 5.0
8.00 .80 1.0 2.5 4.0 7.0
10.00 .80 1.0 3.0 4.5 8.0
12.00 .80 1.0 3.0 5.0 9.0
14.00 1.0 1.0 3.0 5.5 10.0
16.00 1.0 1.0 3.5 6.0 11.0
18.00 1.0 1.0 3.5 7.0 12.0
20.00 1.0 1.0 3.5 7.5 13.0
24.00 1.0 1.0 4.0 8.0 15.0
Notes:
1) Nominal pipe length in feet. Adders are for various in-line pipe fittings to compensate for greater areas of heat loss.
2) Values above are based on an average of various fittings available, with the assumption that fitting insulation will be
equivalent to pipe insulation. The nominal length of tracer to be applied to a particular fitting would be the value
shown in this chart plus the flange-to-flange length of the fitting.
3) For a Flanged Valve Adder choose Valve Type then add one Flange Pair for total adder length.
Flange
Pair
Vent &
Drain
Pipe
Support
Globe, Ball &
Butterfly Valves
Gate
Valve
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GA-2090 Rev. 1
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The following figures show installation details for various typical situations:
Valve
Typical installation method
(may vary for different valve shapes)
Fiberglass Tape
Heater Cable
Elbow
Heater cable should be positioned on
the outside radius of all elbows on
51mm (2") diameter pipes & larger.
Figure 6
Fiberglass Tape
Flange
Heater Cable
Fiberglass Tape
Heater Cable
Figure 7 Figure 8
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GA-2090 Rev. 1
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Page 10
Hanger Support
Bar Hanger
Shoe Support
Side View
Heater Cable
Fiberglass Tape
Do not clamp heater cable
under hanger bracket
Bar Hanger
Heater Cable
Fiberglass Tape
Pipe Shoe Support
Bottom View
Fiberglass Tape
Pipe Shoe Support
Heater Cable
Heater Cable
Figure 9 Figure 10
SYSTEM COMPONENTS
Only Nelson Heat Tracing Systems approved termination, connection and splice kits should be used. Failure to
do so will void warranties and agency approvals. Installation instructions in each component kit should be
followed for heater cable preparation and assembly. Make end seal terminations and splice connections before
making the power connections. It is recommended that all heater cables be tagged as they are installed with a
discrete circuit number. This will facilitate identification, components needed and electrical wiring during later
phases of the installation. Power connection kits utilize an adapter plate kit for installation on instrument tubing
and tanks. Installation instructions for mounting are included in each kit.
!
WARNING:
Connecting bus wires together
will create an electrical short.
Power Connection Kit - PLT-BC, ALT-BC or LT-BC
Node
Node
End Seal - LT-ME, LT-SE or LT-E
In-line splice under insulation (shown) - LT-NSS
Above insulation - PLT-BS, ALT-BS or LT-BS
Heater cable loop
Node
Insulation
Node
Node
Tee splice under insulation (shown) - LT-NST
Above insulation - PLT-BY, ALT-BY or LT-BY.
Node
Pipe Clamps
Fiberglass Tape
Note: Heater cable power connections and end seals are required for each heater cable. Heater cable splices,
tees, and thermostats are used as needed.
Figure 11
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GA-2090 Rev. 1
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Page 11
THERMAL INSULATION
Pre-Installation Checks
Inspect the heater cable and components for correct installation and possible damage. In particular, verify that:
• The proper extra amount of heater cable has been installed at each valve, flange, pipe support, etc.
and that it is free from physical nicks, tears or gouging. Additional cable beyond the specified
amount at a heat sink is not a problem due to the inadequacies of the thermal insulation.
• Connections, splices and end seals are correctly installed, including cable seals at power connection
enclosures.
Installation
Check the thermal insulation type and thickness against the design criteria. Changes in insulation type or
thickness may require a different wattage heater cable. Verify that all pipe work, including wall penetrations,
fittings, etc., has been completely insulated.
Check the system to verify that:
• Insulation is not wet from rainfall prior to the application of waterproofing.
• Lap joints on vertical piping are properly overlapped - higher piece lapped over the top of lower
piece.
• Band seals are used at lap joints to prevent the ingress of water.
• All penetrations of lagging (valve stems, hanger rods, etc.) are properly waterproofed.
• Irregular shaped items (i.e. pumps, filters, valves, etc.) are properly waterproofed.
• Seams in insulation blankets are airtight.
To minimize potential damage to the heater cable, install the insulation as soon as possible. It is recommended
that another insulation resistance (megger) test be done after the insulation has been installed to verify that the
heater cable was not damaged during the insulation installation.
Marking
Install “Electric Trace” signs on alternate sides of the piping at regular intervals, as a warning to maintenance
personnel. Permanently mark the outside of the insulation lagging with the location of heater cable components.
This will facilitate maintenance in case of a problem.
THERMOSTATS & SENSORS
Temperature sensitive applications require the use of a thermostatic control. In selection of the proper
thermostat, consider voltage and amperage ratings of the device as well as the suitability of housing for the
environment (explosion proof, rain tight, corrosion resistance, etc.) Mount thermostat housing as close as
possible to the power connection kit. It may be attached to the power connection kit provided code
requirements are met with regard to conduit connections, seals, etc. To sense the coolest air temperature,
ambient (air sensing) thermostats should be mounted in the shade and away from any additional heat source.
When using pipe-sensing thermostats, the bulb (sensor) should be mounted on the opposite side of the pipe
from the heater, or as far away as is practical. This will allow the thermostat to sense the actual pipe
temperature and not be influenced by the heater temperature. Mount the sensing bulb on the pipe at least three
(3) feet from the closest heat sink if possible.
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GA-2090 Rev. 1
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Page 12
Moisture inside the enclosure will cause both corrosion and electrical shorting problems. The potential for this
type of problem, can be greatly reduced by:
• Proper sealing of all enclosures openings.
• Keeping enclosure cover closed and secured as much as possible during installation sequence.
• Proper closing and sealing of the cover to prevent leaking into the housing.
• Use of a moisture proofing/electrical spray (aerosol) sealant on thermostat and electrical connections
(including all metal parts) at completion of installation.
• Keep conduit fittings, openings, and pull box covers closed.
ELECTRICAL REQUIREMENTS
Voltage Rating
Verify that the heater cable voltage rating is suitable for the service being used. See Nelson Heat Tracing
Systems Design Guide for voltage and wattage ratings, which are also printed on the heater cable.
Electrical Loading
Size over-current protective devices according to Nelson Heat Tracing Systems Literature/Design Guide. If
devices are other than standard thermal magnetic circuit breakers, consult factory.
Ground Fault Protection
Ground fault circuit breakers are required on all heater constructions per the National Electric Code. Typically,
30ma trip devices are recommended due to the capacitive leakage of the heater cable construction.
Waterproofing
Moisture penetration of the electrical system is the single largest source of problems in a heater cable system
installation. Therefore, particular care must be given to the proper sealing of all electrical connections and
splices. Heater cable sealing kits will provide a proper seal for the heater cable itself, when used per kit
instructions. All other electrical connections (heater to power wiring, thermostat connections, panel and breaker
connections, etc.) should be sealed or moisture proofed in some fashion. Either mastic shrink tube or an aerosol
electrical insulative sealant should be used on all connections to reduce any moisture penetration. The sealant
will also reduce the potential for corrosion on exposed metal parts.
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GA-2090 Rev. 1
Sheet 12 of 22
September 2005
Page 13
TESTING
Recommendations
Electrical tests are recommended at specific points in the receipt and installation of the heater cable. This
periodic testing is designed to prevent the expenditure of wasted labor in the even of damage to the product.
Installation costs of the cable and thermal insulation are much greater than the heater cable. Quick identification
of any heater cable damage is the most economic approach to an installation. An insulation resistance test is
recommended at the following points of the installation process:
• UPON RECEIPT of the heater cable
• BEFORE thermal INSULATION installation
• IMMEDIATELY AFTER thermal insulation installation
• As part of a PERIODIC MAINTENANCE program
Procedure
The insulation resistance test is used to check for damage to extruded jackets. Connections for the megger are
made as shown in Figures 12.
Test A - (solid lines) from heater cable bus wires to braid (tests electrical insulation).
Test B - (dotted lines) from braid to metal pipe (tests overjacket on J construction).
500 VDC MEGGER
Figure 12
Note: Test should use at least a 500 VDC megger. Do not use a megger with an excess of 2500 VDC. Minimum
acceptable readings should be 20 megohms per circuit, regardless of length.
A record should be kept of the readings taken from the time the cable is first installed on the pipe. A history of
the insulation resistance reading can be helpful in spotting moisture ingress into the electrical system (by seeing
a gradual decline in the insulation resistance or physical damage to the heater cable (sharp decline in the
insulation resistance). A sample record for this is shown in Figure 13.
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GA-2090 Rev. 1
Sheet 13 of 22
September 2005
Page 14
p
Periodic Inspection Record
Freeze Protection Circuits -
Perform these checks as season
requiring use approaches.
Temperature Maintenance Circuits -
Perform these checks at least twice per year.
Heater Type
Circuit Length
Maintenance Checks for ________________________ Month ___________________ Year_____________
Circuit Number
Visual inspection inside connection box Initial
corrosion, moisture, etc. Date
Damage or cracks (leaks) in insulation Initial
seals at valves, hangers, pumps, etc. Date
Heater cable properly connected and Initial
grounded. Heater cable and connections
insulated from connection box. Date
Thermostat checked for moisture, corrosion, Set Point
set point, switch operation, and capillary Initial
damage Date
Megger tests performed at power Reading
connection with both bus wires disconnected Initial
from power wiring. Date
Circuit voltage at power connection. Reading
Circuit Amperage Reading
Watts/Ft.
Volts x Amps = w/ft. Initial
feet Date
All connections, boxes, and thermostats Initial
have been resealed. Date
End seals, covered splices and tees marked Initial
On insulation cladding. Date
Remarks & Comments
Figure 13
Periodic Inspection Record Form
The Periodic Inspection record Form may be used in one of two ways:
1) One sheet per circuit. - The results of periodic tests of a single circuit are posted in vertical
columns, beginning on the left and working toward the right. This allows easy comparison of test
values for up to seven test sequences on an individual circuit.
2) One circuit per column. - Test data for a single test sequence on as many as seven circuits can be
recorded on a single sheet.
Periodic Ins
ection Record Form
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GA-2090 Rev. 1
Sheet 14 of 22
September 2005
Page 15
START-UP
Heat-up Time
Heat-up capacity (the ability to heat the pipe and its contents rapidly) is not normally designed into the system.
Cold start-ups should allow adequate time for the pipe to come up to temperature.
OPERATION & MAINTENANCE
System Design, Installation & Documentation
The heater cable system must be properly designed, installed and documented. This documentation should at
least included line lists and location identification documentation. As built installation drawings provided the
optimum maintenance tool. Test records should also be considered as part of the system documentation
requirements. See Figure 15.
Preventive Maintenance
A preventive maintenance program is needed which will encompass both visual and electrical checks of the
system. These should be done not only before initial operation of the system, but also on a scheduled basis. The
checks should also be done after any maintenance has been performed.
Visual Inspections
• Thermal insulation - check weatherproofing for damage, missing seals, cracks or gaps in caulking and mastic
coatings, damaged or missing lagging. When damage does exist, the insulation will need to be repaired or
replaced, and then resealed. WET INSULATION HAS POOR INSULATING PROPERTIES, FOR THE
SYSTEM TO OPERATE PROPERLY THE INSULATION MUST BE KEPT DRY. If insulation has
been damaged, check the heater cable for damage - replace the damaged section.
• Inspect junction boxes, connection boxes and thermostats for corrosion, moisture or foreign matter.
• Tightness of electrical connections, proper electrical insulation of heater cable wires, adequacy of moisture
seal on electrical connections and that a minimum of one (1) inch of electrically insulated heater extends
above the grounding connection. No strands of the ground braid should extend above this connection.
• Check all thermostats or sensor capillary leads to verify they are tied back and shielded from physical
damage.
• Verify all enclosure, connection box, etc. covers are properly closed and that the thermostat is switching off
and on by measuring current flow in the circuit when the unit switches on. Reset the knob to the proper
temperature after completion of the test.
Frequency
Inspections should be made prior to the start of the freeze season on freeze protection systems. Process
maintenance systems should be checked on a frequent base, at least twice a year.
Personnel Training
Qualified maintenance personnel must be used to maintain the system. It is recommended that periodic training
programs be utilized to assist in keeping maintenance personnel up to date on equipment and procedures.
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September 2005
GA-2090 Rev. 1
Sheet 15 of 22
Page 16
Maintenance
The heater cables will not require any maintenance. Mechanical temperature controls should be sprayed with a
moisture repellent/corrosion inhibitor once a year on all metal parts.
Piping Repairs
Disconnect the electrical connection for the heater cable and protect it from mechanical or thermal damage
during the repair. Check the heater cable installation after the repairs per established procedures. Replace and
water seal the thermal insulation system.
DAMAGED PRODUCTS
• Do not attempt to repair a damaged heater cable - replace the entire section.
• Replace the damaged heater cable immediately. Moisture migration into the good section of the heater cable
may cause electrical shorting in that cable after repair of the damaged section.
• Any product exposed to fire or flame should be removed from service immediately and replaced. Further fire
damage could result if energized.
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GA-2090 Rev. 1
Sheet 16 of 22
September 2005
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TROUBLESHOOTING
SYMPTOMS PROBABLE CAUSE CORRECTION
Branch Circuit Breaker Trips
2. Circuit oversized
3. Defective circuit breaker. 3. Replace circuit breaker.
4. Connection and/or splices
5. Physical damage to the
6. Wires connected at end
7. Excessive moisture in
8. Nick or cut in heater or
*Check to see if existing power wire sizing is compatible with larger sized breakers.
**To locate shorting problems, follow these steps:
1. Circuit breaker undersized 1, 2. Re-establish what the current loads are
going to be and resize the breakers.*
4, 5. Locate and repair incorrect connections,
may be shorting out.
heater cable may be
causing a short.
seal.
connection boxes or
splices.
power feed wire with
moisture present.
splices, or damaged sections of heater
cable.** Megger per installation
instructions.
6. Disconnect wires and perform a current
check for possible other damage.
7. Dry out and re-seal connections and
splices. Megger per Installation
Instructions (20 megohms min.) Work on
connections outside the thermal
insulation first, going to the below
insulation connections and seals after the
others have been eliminated.
8. Locate and repair or replace damaged
heater cable or power wire.**
1) Visually inspect the power connections and splices that are outside of the thermal insulation for proper
installation.
2) Check around the valves, pumps, and any area where there may have been maintenance work done, for
visual indications of damage.
3) Look for crushed or damaged insulation lagging along the pipe.
4) Inspect heater cable splices under the thermal insulation.
5) If you have not located the problem by now, you will have to isolate one section of the heater cable at a
time until you determine the general area of damage. First, isolate by disconnecting any tees or splices
then remove insulation from that area until the specific damage is found. For long runs of cable, it may
be necessary to cut the cable in half to isolate the shorted section.
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GA-2090 Rev. 1
Sheet 17 of 22
September 2005
Page 18
SYMPTOMS PROBABLE CAUSE CORRECTION
Power output is zero or
lower than rated. (1)
2. Circuit is shorter than design
a. Splices or tees may not
b. Heater cable may have
3. Improper crimping causing a
4. Control thermostat is wired in
5. Heater cable has been
6. Heater cable has been
Power output appears
correct but pipe
temperatures are below
design value.
2. Insufficient heater cable was
1. Low or no input voltage. 1. Repair electrical supply lines and
equipment.
2. Check routing and length of heater
shows.
have been connected.
been severed.
high resistance connection.
the opened position.
exposed to excessive
moisture.
exposed to excessive
temperatures.
1. Insulation is wet. 1. Remove and replace with dry
used on valves, supports, and
other heat sinks.
cable (use “as-builts”), and recalculate
power requirements.
a. Connect and recheck the power.
b. Locate and repair the damaged
heater cable. Recheck the power.
3. Re-crimp using correct procedure.
4. Rewire in the normally closed
position.
5, 6. Replace the heater cable.
insulation and insure proper
weatherproofing.
2. Splice in additional heater cable but
do not go over maximum circuit
length.
3. Thermostat was set incorrectly 3. Reset the thermostat.
4. There are thermal design
inconsistencies.
4. Check with the local or factory
representatives for design conditions.
Modify as recommended.
(1) Calculate the power (watts / ft.) of the heater cable by multiplying the current by the input voltage and dividing by
the actual circuit length, I x V / Ft. = Watts / Ft.
P.O. BOX 726 TULSA, OK 74101 TEL 918-627-5530 FAX 918-641-7336 www.nelsonheaters.com
GA-2090 Rev. 1
Sheet 18 of 22
September 2005
Page 19
HEAT TRACE INSTALLATION RECORD
1. Circuit No._______________________________
2. Receiving Documentation Date _____________________________________________
Item DESIGN ACTUAL
A. Cable Type _______________________ _______________________
B. Cable Length _______________________ _______________________
3. Receiving Testing Date _____________________________________________
A. Check for physical damage O.K. ___________________ Damage_________________
B. Continuity Check
Check for continuity between power leads. O.K. ___________________ Open ___________________
C. 500VDC min., 2500VDC recommended,
megger check between leads and
sheath, 20 megohms min. Megohms_________________________________________
D. Lot No. No. ______________________________________________
4. Post Installation Testing Date _____________________________________________
A. Continuity Check
Check for continuity between cold leads. O.K. ___________________ Open ___________________
B. 500VDC min., 2500VDC recommended,
megger check between leads and
sheath, 20 megohms min. Megohms_________________________________________
C. Visually Check Cable Installation Prior to
Release for Thermal Insulation. Visual Check O.K. __________________________________
5. Final Testing and Commissioning Date _____________________________________________
A. Circuit approved for testing by client. Approved _________________________________________
B. 500VDC min., 2500 VDC recommended,
megger check between leads and
sheath, 20 megohms min. Megohms_________________________________________
C. Energized Testing
(all test data to be within 10% of design data) DESIGN ACTUAL
1. Circuit Voltage _______________________ _______________________
2. Initial Current _______________________ _______________________
3. Pipe temperature _______________________ _______________________
6. Circuit Acceptance _______________________ _______________________
This circuit has been tested and documented in accordance with the above itemized data. This circuit by:
Contractor _____________________________________ Date _________________________________________
Client _________________________________________ Date _________________________________________
The Heat Trace Installation Record can be used to monitor the initial installation and check out process. This
form can be used in conjunction with the Periodic Inspection Record shown in Figure 13.
Figure 14
P.O. BOX 726 TULSA, OK 74101 TEL 918-627-5530 FAX 918-641-7336 www.nelsonheaters.com
GA-2090 Rev. 1
Sheet 19 of 22
September 2005
Page 20
POWER TERMINATION INSTALLATION
Overjacket Stripping Procedures
(For Braided Products, proceed to step 4 below)
Node
229mm (9")
!
WARNING:
DO NOT CUT BRAID
102mm (4")
n Lightly cut around heater cable overjacket 102mm
(4”) from the end. Bend cable to break overjacket.
Note: The node should be within 152mm (6”) of
termination. Cable heats between nodes; this is
called the heating zone. Cutting the cable between
nodes destroys the heating zone.
o Lightly cut overjacket up the center between the
first cut mark and cable end. Bend cable to break
overjacket.
p Remove overjacket from heater cable exposing
cable braid.
q Push cable braid back toward overjacket, creating
a bulge.
Braided Products:
Tape braid in place 102mm (4”) from cable end
using fiberglass tape.
r At the bulge, separate braid to make an opening.
s While bending the heater cable, work it through the
braid opening.
t Pull braid tight.
u Proceed to “Outer Jacket Stripping Procedures”.
P.O. BOX 726 TULSA, OK 74101 TEL 918-627-5530 FAX 918-641-7336 www.nelsonheaters.com
GA-2090 Rev. 1
Sheet 20 of 22
September 2005
Page 21
Outer Jacket Stripping Procedures
Node
102mm (4")
76mm (3")
152mm (6")
n Lightly cut around heater cable outer jacket 76mm
(3”) from the end. Bend cable to break outer jacket.
Note: The node should be within 152mm (6”) of
termination. Cable heats between nodes; this is
called the heating zone. Cutting the cable between
nodes destroys the heating zone.
o Lightly cut outer jacket up the center between the
first cut mark and cable end. Bend cable to break
and remove outer jacket.
Power Termination
3.175mm (0.125")
remove
r Remove all but approximately 3.175mm (.125”)
from the power termination.
s Slide the power termination halfway over th e
insulated bus wires. At this point, do not slide the
power termination up against cable outer jacket.
apply silicone here
p Remove outer jacket from heater cable exposing the
insulated bus wires.
Resistance Wire
q Completely remove the resistance wire and clear
inner jacket back towards the outer jacket exposing
the insulated bus wires.
t Squeeze the power termination open and fill
with silicone.
u Continue sliding the power termination over the
insulated bus wires overlapping the cable outer
jacket.
13mm (.5")
v Strip 13mm (.5”) of the end of each insulated
bus wire.
P.O. BOX 726 TULSA, OK 74101 TEL 918-627-5530 FAX 918-641-7336 www.nelsonheaters.com
September 2005
GA-2090 Rev. 1
Sheet 21 of 22
Page 22
END SEAL INSTALLATION
Overjacket Products
Node
51mm (2")
38mm (1.5")
n Remove 38mm (1.5”) of cable overjacket.
Note: The node should be within 51mm (2”) of
termination. Cable heats between nodes; this is
called the heating zone. Cutting the cable between
nodes destroys the heating zone.
o Then push braid back over the overjacket.
p Proceed with step 4 next column.
Braided Products
Node
Node
51mm (2")
13mm (.25")
q Lightly cut around and up the center of the heater
cable outer jacket 13mm (.25”) from the end. Bend
cable to break outer jacket and remove.
r Completely remove the resistance wire and clear
inner jacket back towards the outer jacket exposing
the insulated bus wires.
51mm (2")
38mm (1.5")
s Spread insulated bus wires apart.
Fiberglass Tape
n Tightly wrap fiberglass tape around braided
cable 38mm (1.5”) from cable end.
Note: The node should be within 51mm (2”) of
termination. Cable heats between nodes; this is
called the heating zone. Cutting the cable between
nodes destroys the heating zone.
o Push braid back over the fiberglass tape.
p Proceed with step 4 next column.
t Squeeze the end termination open and fill
with silicone.
u Slide the end termination over the insulated
bus wires.
Nelson Heat Tracing Systems products are supplied with a limited warranty. Complete Terms and Conditions may be found on Nelson's
website at
www.nelsonheaters.com.
P.O. BOX 726 TULSA, OK 74101 TEL 918-627-5530 FAX 918-641-7336 www.nelsonheaters.com
GA-2090 Rev. 1
Sheet 22 of 22
September 2005
Page 23
Page 24
©
Copyright 2005 GA-2090 Rev. 1
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