Frequently Asked Questions (FAQ)

Frequently Asked Questions (FAQ)


The bend radius is: NEC - 5 times the cable diameter for cables 3/4"" and smaller in diameter and 10 times for cables larger than 3/4""    CEC - 6 times the cable diameter for cables 3/4"" and smaller in diameter and 12 times for cables larger than 3/4"".

The cable is annealed at the factory, which softens the copper (or stainless steel) and makes it easier to bend. Bending the cable will cause the sheath to harden, making the cable more difficult to bend. The sheath thickness of the specific cable will make a difference in the number of times it can be bent back and forth. However, on average, if the cable is bent 180° in one direction, then back 180° in the other direction, then bent back 180° in the first direction, it will probably break.

You can use a hot torch to heat the cable at the bend to soften the cable - which should allow it to be bent again.



It is recommended that MI cables be run as close together as possible to ensure that sheath voltages and currents are kept to a minimum. Bundling single conductor causes the magnetic fields surrounding the cables to cancel, reducing the sheath voltages. Refer to the Engineering Data Manual, 011-EngData - ENGINEERING DATA MANUAL, available on our web site, for recommended method to bundle and group cables.


Two options are available to you; 1.) Install a subpanel that will accept EPD breakers, 2.) Install electronic controllers, such as the DigiTrace 910 or 920, that have ground fault interrupters built into them. Data sheets  and installation manuals for the 910 and 920 DigiTrace controllers are available on line.


"The reason a ground fault circuit breaker does not trip when a cable is shorted is because the bus wires short together but not to the braid, which is grounded. Current flow is between the bus wires only. Usually, the circuit breakers trips on high current.

If the braid is not properly grounded, the breaker may not trip when there is a bus-wire short to braid because there is no current imbalance from leakage to ground. The braid should be connected to a ground wire that connects to the distribution panel ground bus, which in turn is connected to the transformer ground.

Incorrect wiring of the branch wires to the GFEPD breaker can also result in a no-trip event. All branch wires must be landed on the circuit breaker, even the neutral wire on a 120V or 277V load. A separate pigtail or jumper wire from the circuit breaker must be landed on the neutral bus to power the electronic ground fault interrupter circuit in the breaker. "


Yes. Just land one of the circuits on the terminal strip marked HTC-01-A terminals 1 and 3 and the other circuit on HTC-01-B terminals 1 and 3 (assuming a voltage range of 120Vac-277Vac phase to phase or phase to neutral).


If the panel and the methane line are in the same area (classification wise), the electrical panel would either be "explosion proof" suitable for either Class I Div 1 or Div 2 under the Class and Division system or "Flameproof" EXd IIC suitable for Zone 1 or Zone 2 under the IEC approach. This is because the panel contains circuit breakers. So even in a Div 2 area you need explosion proof equipment. The exception to this is if the panel was purged (Z-type for example).


Circuit breakers have a time vs. current response curve. We use these curves to establish the maximum heating cable circuit length for a given circuit breaker at various startup temperatures and voltages. Self-regulating cables draw more current when they first start up, especially at low temperatures. Through testing we know how much current our cables draw at any given time. As long as the cable current does not exceed the circuit breaker trip current at any given time during start up, the breaker can be used. For a complete discussion on the circuit breaker current response curves, point your web browser to$FILE/0600DB0105.pdf. Also taken into account is Section 427-4 of the National Electrical Code states that a circuit breaker cannot be loaded to more than 80% of its full-load rating. Therefore, maximum cable circuit lengths are set so that at steady-state (approx. 5 min.) the current will not exceed 80% of the circuit breaker rating. Always use the Maximum Continuous Circuit Length Per Circuit Breaker tables in the data sheets for our cables to design heat tracing circuits.


The section of the National Electrical Code which addresses ground fault  protection of branch circuits supply fixed electrical heating equipment is  Article 427-22.


GFI outlets have a 5 mA trip level. It might produce "nuisance tripping" but it might work if the heating cable circuits are not very long.  We recommend a 30 mA trip level GFPDs, which are available as circuit breakers, to prevent nuisance tripping.  Nuisance tripping happens because there is a certain amount of "leakage" inherent in a self-regulating heating cable.  The longer the heating cable, the more leakage.


The 22A rating is based on the steady-state load. This is because the arcing occurs when the contacts open, not when they close. This is due to the collapse of the magnetic field around the conductors when the circuit opens, causing a inductive current. You'll see it sometimes in a light switch when you turn it off at night.


Yes. TraceCalc Pro includes products suitable for a variety of hazardous areas.


The TraceCalc Net™ is a simple, Web-based tool for single line applications. TraceCalc Pro is a multi-line design tool that can be downloaded from our Web site.


All product questions should be directed to the Technical Hot Line at 650-474-7709. You can also design MI cable with TraceCalc Pro.


The latest version of TraceCalc Pro (v2.6) will show the estimated "Contact Temperature".  This is the temperature where the heater cable touches the plastic pipe.  You should also enter the Maximum Allowable Temperature for the pipe.  In TraceCalc Pro, the definition for Maximum Allowable Temperature is:  "the maximum temperature permitted by the user for the process/fluid or piping" .  The program will compare the Contact Temperature against the Max. Allowable Temperature and issue a warning if it is exceeded.  Even if you don't receive this warning, you should closely review the reported Contact Temperature to determine if it is compatible with your piping system.


As long as the correct heating cable is selected for the pipe, it should have no effect on it. Use BTV heating cables for plastic and metal pipes. QTVR can be used conditionally on plastic pipes, however, TraceCalc Pro should be used to test weather QTVR can be used on plastic pipes.


All cables manufactured by nVent Thermal Management except RMI, Gardian and Frostex Plus have splice kits available. Assuming you have an industrial heating cable, the splice kits available are, PMKG-LS and S-150 (under-insulation), T-100 and JBM-100-A (above-insulation). For WinterGard cables use the H910 Slice/Tee kit. The damaged cable should be removed and a piece of new cable spliced in with two of the above-mentioned splice kits, unless there is enough slack cable to allow one splice kit. Installation instructions for these kits are available on line at


The 2000 hour immersion test is the IEEE 515.1-1995 Increased Moisture  Resistance Test.  The heating cable, including terminations and  connections, is immersed in water at 10-25C (50-77F) for a period of 2000h  (12 weeks).  After conditioning, the sample is subjected to the dielectric  voltage test (2 times the rated voltage plus 1000) for 1 minute without  dielectric breakdown.  This type test is required for heating cables  exposed to outdoor locations (roofs, gutters, downspouts,etc.).  The  standard IR test is done at room temperature and the sample is immersed in  tap water and a dc voltage of 2500 Vdc (IEEE 515-1997) and 500 Vdc (IEEE  515.1-1995) is applied between the conductors and water.  Water ingress can adversely affect the power output of self-regulating  cables if the water is wicked into the bus wires. This increases the  contact resistance between the heating core and current carrying bus wires  which reduces the current that can flow through the core to produce heat.  An annual insulation resistance (IR) test can help in determining if damage  to the cable jackets has occurred. Moisture penetrating the jackets can he  wicked through the bus wires, if exposed, and "kill" the heating cable  core. Also, moisture can be wicked up the braid and into the junction box  or end seal and enter the bus wires that way. This doesn't happen often  because the whether barrier around the thermal pipe insulation usually  keeps moisture from the cable. Sections 8 and 9 of the Self-Regulating and Power Limiting Heating Cable Systems Installation Manual cover procedures for periodic  maintenance and testing cables. Section 11 is an Inspection Record form  that can be used to document your visual inspections and tests. The Guide  is available on line at under Installation and  Maintenance Manuals.


There are five papers written on Steam vs. Electric tracing. The article names and numbers are; CEP Article "Heat Tracing, Steam or Electric" - # 55454, IEEE Paper: Study of steam vs. electric pipeline heating costs - #54620, CEP Article "Choose the Right Heat-Tracing System"-#54218, EPR Article "Electric Tracing in a Chemical Plant" - #55520, Hydrocarbon Processing "Heat tracing stream or electric?" - #53413. In addition, we also have a computer program called ASAP that can directly compare a proposed steam vs. electric system. Call your local nVent Thermal Management representative if you would like an analysis done for your facility.


The best way to produce data for your  specific application is to use TraceCalc Pro Heat Tracing Design  Software available on our web site by clicking on the Software link or  from your local nVent Thermal Management representative. TraceCalc Pro will  calculate what the maximum uncontrolled pipe temperature will be using  RAYCHEM 5BTV cable. PVC pipes have a 160°F maximum exposure temperature. The  following example employs RAYCHEM 5BTV1-CT on a 1" PVC line with 2" fiberglass  insulation on a 100°F day. As you can see, the pipe temperature would  not exceed 128°F, well below the max. exposure temperature for PVC.  TraceCalc follows IEEE 515 guidelines for calculating heating cable  sheath temperature and uncontrolled pipe temperature and is FM Approved.


All Industrial and Commercial Construction heating cables are warranted against factory defect for 10 years. This warranty is valid if you install and test the cables according to our instructions and use nVent Thermal Management components. All of our cables are designed to last at least 20 years, however, many installed in the 1970s are still working today.


At 40 amps, often the limiting factor in the circuit length is the voltage drop on the cable. The longer the cable, the higher the voltage drop. If the voltage at the end of the cable falls below a certain level, we cannot guarantee that it will produce enough power to maintain the pipe at the specified temperature. If you have a circuit breaker that has multiple cable circuits, at varius wattages on it, use the maximum circuit length specified for the highest wattage cable at the strart-up temperature, voltage and circuit breaker size you design to. Remember to use the circuit length adjustment factor for voltages other than 240V. E.g., RAYCHEM 10BTV2-CT powered at 208V has an circuit length adjustment factor of 0.92. Therefore, if the maximum circuit length is 360 feet at 240V, it would be only 331 feet at 208V.


Yes. Self-regulating heating cables rated for 240V can be used on 208V, 220V, 240V and 277V circuits. The power output is rated at 240V, so when powered at 277V the power output increases. At 208V the power output decreases. Example, RAYCHEM 20XTV2-CT will produce 20W/ft at 240V on a 50°F pipe. At 277V it produces 22W/ft, and at 208V it produces 17.5 W/ft on a 50°F pipe.


Self-regulating heating cables are primarily installed on pipes for freeze protection and process temperature maintenance, under floors for floor heating, in concrete slabs for snow melting and on roofs for de-icing. You will find them in industrial plants, in and on commercial buildings and residential buildings. If you would like a reference list for your area, please call 800-545-6258.


Yes. But be sure not to exceed the maximum circuit length for the highest wattage heating cable considering the circuit breaker and start-up temperature used.


No.  This will void the approvals, such as Factory Mutual or CSA, for the box if the installer drills additional holes.


No. Our components are appoved by Factory Mutual and other agencies as they come packaged. Modifying them will void agency approvals.


Yes. But all power cables would have to enter through the same conduit  since there is only one conduit hole in the junction box. I assume you want  to daisy-chain the incoming power to another circuit. By using the spare  terminals that are jumpered together on the terminal block, a second set of  conductors could be terminated in the box and continue power to another  circuit. Do not terminate two conductors in the same terminal. Care should  be taken to see that the maximum steady-state amperage rating of 50A is not  exceeded by the combined load.


No. Modifying the connection kit will void agency approvals.


The RAYCHEM JBM-100 can only do one circuit at 50 amps due to the required wire gauge size.  That is because there is only a 3/4"  conduit hole. For two circuits of 50 amps you would require a conduit larger than 3/4".  If the amperages of the circuits are low enough so that the power wiring can be pulled in a 3/4" conduit then it is okay to use the multiple circuits.


Tank heating is similar to pipe heating only on a larger scale.  A water tank in a cold environment might need freeze protection to prevent the water from freezing.  An oil tank might require heat tracing to keep the oil flowing.  Many chemicals, food products, etc., need to be kept at certain temperatures so they will not degrade or corrode, etc.  An example would be chocolate.  If chocolate gets too cold, it will solidify, and if it gets too hot, it will burn. Tank heating can be accomplished using heating cables wrapped around the tank to offset the heat loss. Self-regulating heating cables such as RAYCHEM BTV, QTVR, and XTV are ideal for tank heating when design and installation flexibility are required. Power-limiting heating cables such as VPL feature high power output to maintain temperatures up to 300F.  Mineral insulated cables such as the PYROTENAX MI cable offer a very reliable solution and are recommended for maintain temperatures above 300F.   The RAYCHEM RHS tank heating pads are selected when high watt density is required.  The RAYCHEM RHS system provides heat to selected areas on the tank.  The heat is then distributed through convection in the fluid.


The method and location for attaching the heating cable or tank pad might be different for each type tank. Click on this link: (1634)

AT180 tape is typically used for plastic pipes and tanks. Because plastic is a poor heat conductor, self-regulating cables do not produce their rated power output on them. Installing aluminum tape over the cable increases the power output. AT180 tape is also required when installing heating cables on steel tanks. We recommend GS-54 fiberglass tape for attaching heating cables to stainless pipe. GS-54 tape does not contain Halides which have been known to cause stress cracking in stainless steel.


The controller injects a 1mA current into an RTD, and measures the voltage drop across it to determine temperature. At 32°F, the voltage drop will be approximately 100mV (depending on the lead resistance of the wires going to the RTD).


We do not sell the replacement core sealer for the E-100-L-A lighted end seal kit. However, the CS-100 core sealer will work provided they shorten the “legs” so that it looks like the ones for the E-100-L-A. Page 4 of 8 of the E-100-LR installation manual has a good picture of this. See the print screen at the bottom.


Standard wire lubricant such as Ideal Yellow 77 will work since this is a thermal plastic rubber (TPR) jacket. Keep the cable ends sealed and dry.


No, the cables are design for use on fixed piping only.


All of our agency approvals are dependent on installation according exactly to our instructions. As our instruction make no provision for multiple power connections in one box, this cannot be done without losing the system’s CID1 rating.​


No fire rated box systems, or listed insulation matting systems, nor gypsum layer assembies, have been tested for use with MI cable terminations. Use of these systems for MI cable splicing may affect the performance of the cable, and will affect the UL system listing of the MI cable. These boxes, and or, assemblies often carry their own fire ratings, and therefore that section of the MI wire system's performance, will be reliant on the box, or assembly listing, of that vendor, and not nVent Thermal Management. It is recommended that use of these assemblies in a MI fire rated wiring system, be reviewed by nVent Thermal Management and the AHJ involved.


​​The controller can be mounted flat against a normal surface, such as a wooden or metal surface.​


​​The minimum spacing should be 4" between the SSR heatsinks. This will provide enough room in the event that an SSR assembly needs to be added or removed. ​


There are 2 stop bits. This value cannot be changed.


The recommendation is to use the Quick Termination system to transition to THHN. Most equipment landing is not appropriate to solid conductors of larger sizes. Also, the majority of our Quick Terminations supplied to the market involve sizing up the THHN, to accommodate for the temperature and current rating when landing on equipment in non-ventilated (non-free air conditions) equipment. The Quick Terminations for the 500 MI cable are available with THHN options of 600 kcmil or 750 kcmil, upon request.


NGC30 and NGC40 panels require to be ordered as a complete unit.  If a panel requires spare circuits, these need to be included in the panel at the time of order.


RTD wiring is always recommended to be run in a separate conduit than high voltage to reduce the likelihood of noise interference. If run in the same conduit, there is a higher chance of noise being induced on the RTD wiring (even if the wire is shielded).


As long as there are no terminations done within the C1D1 area, then the standard connection kits can be used. However, the C1D1 hazardous area connection kits must be used if any terminations are within the C1D1 area. CID1 rated cable is required and all hazardous area forms must be filled out and sent to nVent Thermal Management before the cable can be shipped.


​In the US, OSHA requires certain products be tested and certified by an the Nationally Recognized Testing Laboratory (NRTL) NRTL. NRTLs are private sector organizations that are recognized by OSHA to perform this certification. Each NRTL has a scope of test standards that they are recognized for, and each NRTL uses its own unique registered certification mark(s) to designate product conformance to the applicable product safety test standards. The NRTL mark signifies that the NRTL tested and certified the product, and that the product complies with the requirements of one or more appropriate product safety test standards. NRTL’s include UL, FM and CSA.


IEEE 515 is a product standard for “Testing, Design, Installation, and Maintenance of Electrical Resistance Trace Heating for Industrial Applications”.  The standard is published by the Petroleum & Chemical Industry Committee of the IEEE Industry Applications Society.  The American National Standards Institute (ANSI) has accredited the IEEE 515 for certification of trace heating products in the US.


The default value is NC. If a change is required please press "Shift" and then "Enter", make sure that the controller "Feature Mode" is set to "Advanced". Scroll down until you see "Misc. Setup" press "Enter" scroll down until you see "Alarm Output" press "Enter" scroll down until you see the desired value and press "Enter"


The default value is NC. If a change is required please press "Shift" and then "Enter". Scroll down until you see "Common Setup" press "Enter" scroll down until you see "Alarm Output" press "Enter" scroll down until you see the desired value and press "Enter"


The RAYCHEM self-regulating heating cable technology consists on two parallel conductors embedded in a conductive polymer heating core. The core is radiation cross- linked to ensure long-term reliability. The selfregulating heating cable automatically adjusts power output to compensate for temperature changes. As the temperature drops, the number of electrical paths through the core increases and more heat is produced. Conversely, as the temperature rises, the core has fewer electrical paths and less heat is produced.


​It is a measured value. The magnitude displayed will be affected by the Voltage Turns ratio number.


The Bridge will recognize the HTC from its “heartbeat” and they will need to delete the old HTC.


A good reference that can be used is document number H58087 NGC40 HTC-IM.


"This alarms a failure of the temperature sensing element designated as the control element by the TS CONTROL MODE setting. Depending on the chosen TS FAIL MODE and TS CONTROL MODE, the output switch may be latched off or on until this failure is corrected. Cause of Alarm: 1) Incorrect or damaged field wiring—open leads or excess resistance (either intermittent or continuous) may be due to broken or damaged wires or loose terminals. 2) Damaged or inoperative temperature sensors."


No, is optional but is Touch 1500 is not installed customer will need to use DTS Software to configure and monitor the panel.


​Yes, the UIT is required in a NGC30 panel.


​One, but in the system, up to 8 RTD’s can be assigned to one circuit.


Yes, the RMM2 is compatible with an NGC40 system.


No, DTS Software Enterprise should be purchase as a package including the SQL license.


To activate your copy of DigiTrace Supervisor Standard: From the main DigiTrace Supervisor screen on a Client computer, click the Help pull down menu and select Software License, then Activate. The License Activation screen will be displayed. Select Activate DEMO Version from the Activation Type drop down box.  Click the Generate Request Code button and a Request Code will be filled in for you. Once you have the Request Code, you can use it to get an Activation Code from nVent Thermal Management. To activate go to the  Use the DigiTrace Supervisor Registration selection to start the activation process. You must have your Request Code available as you will be asked to provide it. An Activation code will be sent to you via the email address under which you registered on. Once you have obtained your Activation Code, enter it into the Activation Code boxes and click the Activate Now button.


Multiple communications ports are supported, allowing serial and Ethernet connections to be used with external devices. 2 RS485 ports, 1 RS232 port and 1 Ethernet.


No, the ProtoNode gateway is only available for a C910 and ACS30 controller.


​1-RS485, 1-RS232 and 1-Ethernet.


Yes. Install the RS485 upgrade Kit for both controllers. Catalog Number: 920KIT*485


No. The components for WinterGard and BTV cables are different and only approved for the specific cables on the instructions sheets. Use either the T-100-A or S-150-A to splice BTV cables and the H910 kits to splice WinterGard H612 cables.


Yes. Self-regulating cables can be crossed over. They reduce their power output at the point they touch each other and never get hot enough to burn out.


None of our products are classified for Class 1E areas. We sell commercial grade materials only however we do sell them into the Nuclear Market.


Yes, the E-100-LR replacement light kit can be used to make an E-100-A into an E-100-LR-A.  However, the approvals label are different for the E-100-A and E-100-L, and those products have different maximum ambient temperature ratings.  The approvals label is located on the stand, not on the top of the unit.  Therefore, the old E-100-A label must be removed from the installed stand and affixed with a new E-100-L label.  This can only be done by a nVent personnel (this does not include distributors or end-users).


Electric heat tracing of hoses is not recommended if the hose is used in a high or constant range of motion application. Industrial service heat trace cable must be hard wired to the power source per electrical code. Components associated with the installation (thermostat) must also be hard wired to the power source. Hose must be capable of withstanding the sustained maximum heat output of the selected heater cable. Application of heater cable on hose: A)Lay down a layer of aluminum adhesive tape on hose. B)Apply heating cable over aluminum tape. C)Cover heating cable with a second layer of aluminum tape. D)Aluminum tape helps to prevent a hot spot on the hose that may cause degradation over time. Aluminum tape also acts a heat fin to help disperse heat around the hose.


Their technical support informed that the minimum installation temperature is 40ºF. Once you hit low 30s, the curing process will be prolonged and the adhesion properties will be significantly reduced.


GS-54 tape does not have halides in it. Halide ions have chlorides in them which can cause stress cracking of the stainless pipe so we say to use GS-54 tape over GT-66 tape. The adhesive on GS-54 tape is stickier at lower temperatures that GT-66. GT-66 doesn’t adhere well at temperatures below 40F.


The sensor cable may be extended to a maximum of 100 ft (30 m) using a 3 wire (twisted shielded pair plus ground) with a wire gauge size of 20 AWG or larger.


The Powered Splice is accomplished by powering two cables from the same power connection kit. This would be a JBM-100-A.


The IO module has a reset button on it in the upper righthand corner (D). Just press it with a paper clip or similar small tool. If the fault has been cleared, it should revert to  normal operation. Also check that the Devise Reset Alarm is disabled in the software.


No. VLKTV is engineered by our tech support group at


No, handling this length & weight is too much.


Our 600V rated cables are tested to 2.2kV, for hi-pot purposes only. We don’t recommend MI cable for VFD purposes, since the cable design has not be optimized for PWM conditions. For VFD considerations, I recommend you discuss with Rockbestos or Belden, since they make a VFD cable with symmetrical grounds.


None of our products are classified for Class 1E areas. We sell commercial grade materials only however we do sell them into the Nuclear Market.


Yes, the E-100-LR replacement light kit can be used to make an E-100-A into an E-100-LR-A.  However, the approvals label are different for the E-100-A and E-100-L, and those products have different maximum ambient temperature ratings.  The approvals label is located on the stand, not on the top of the unit.  Therefore, the old E-100-A label must be removed from the installed stand and affixed with a new E-100-L label.  This can only be done by a nVent personnel (this does not include distributors or end-users).


1. Electric heat tracing of hoses is not recommended if the hose is used in a high or constant range of motion application.
2. Industrial service heat trace cable must be hard wired to the power source per electrical code.
3. Components associated with the installation (thermostat) must also be hard wired to the power source.
4. Hose must be capable of withstanding the sustained maximum heat output of the selected heater cable.
5. Application of heater cable on hose:
a.) Lay down a layer of aluminum adhesive tape on hose.
b.) Apply heating cable over aluminum tape
c.) Cover heating cable with a second layer of aluminum tape.
d.) aluminum tape helps to prevent a hot spot on the hose that may cause degradation over time. Al tape also acts a heat fin to help disperse heat around the hose.


The would be the catalog number of the replacement 920 controller: 920*E2FWL*SIS301*SS3301*HTC*CON


No brass plate need. You only need a brass plate for iron based enclosure materials.


I would recommend minimizing the separation of the conductor bundles as possible, to limit any induced effects. We do not have any data to offer you to determine the flux strength generated in the structural beam based on conductor separation duration and proximity.


You can use metal clips to secure the cable preferably conduit clips since they are made for this application.


No, that is only for 1/2" terminations, and 4/12-465 is a 3/4".


No, just an electrical box rated for the area. Most tend to be standard NEMA 1/12 painted steel boxes.


No, it can  get  wet. It is outdoor rated but  cannot be submerged.


If you only have one row of SSRs, you could get away with 1” between SSRs, but if there are two or 3 rows on the side of the enclosure, you would need 4”. You need to be able to remove the SSRs in the back row if required. We always recommend 4” so the customer only have to remember one number.


It appears that you would like to create power children on a “power, parallel” segment (a power, parallel line with a power, splice or power, tee child). You are correct: logically, in a power, parallel configuration you should be capable of having more than one cable originate in the junction box. However, the feature has not yet been implemented in the software. TraceCalc Pro is not yet capable of correctly designing a circuit in which power parallel lines have power children. This feature request is already on our list, but it has not yet been scheduled for implementation. I know of no ‘workarounds’ other than to simply design the power, parallel line as a ‘parent’ and then combining the startup and operating currents and loads after the fact to ascertain the circuit breaker and supply line loading.


Country of Origin for A-180 is China so it does not qualify for TAA approval.


The AMC-1A is made in the US. It should be marked on the label.


I believe that the panel configurator at Partner’s Corner allows both options, although this is not the case. The 920 controller can only be built with either the ALM or HRM relay; it is not possible to build it with both options. The *ALM option is a rail mounted SSR FormA relay (which has about 1 – 2 mA of leakage current across it when it is off – not liked by some DCS / PLC system which are monitoring for alarms). Best suited for driving pilot lights and beacons. The contacts can either be open or closed, but will always be open with loss of power. The *HRM option is a 2FormC relay, and has two sets of dry contacts. One set can be used for a local pilot light, and another set for as a remote alarm. The contacts are NO & NC, so even in the event of power loss, you can have either type of contacts.


TCPro will calculate the individual loads for each cable type and combine them to see if they exceed 80% of the total circuit breaker capacity. In this case, using 5BTV2 on the 2” line and 3BTV2 on the 1” line will work fine (19.3A on startup). The unjointed length error implies that you need to break the total heating cable run into multiple pieces, usually accomplished with a splice kit. However, since you have a tee connection for the 1” branch line, this will serve as a “joint” and break the total heating cable run into 2 pieces. The 1” flexible foam insulation is more like a flexible elastomer, which is listed as “FE” in TCPro.


The only way we can determine a sheath temperature other than the allowable T-rating for the heating cable is to use TraceCalc Pro. This is because there are too many variables involved to do a calculation by hand. It is possible to get an actual sheath temperature with TraceCalc. Assuming this is a hazardous area, enter an AIT that is a bit below the temperature of the T-rating. For example, if the T-rating is 200C, enter 195C. It should then give you the stabilized sheath temperature for the heating cable.


Connection and Protection