Heat Trace Cable - Heating Cable

Heating Cable

As winter is upon us, it is time to think of freeze protection and keeping pipes warm. Heating Cable is one way to do this, we sell electric heat trace. All heat tracing requires INSULATION. It will not work without it.

There are two main types of heating cable; self regulating and constant wattage.

Self-regulating cable
Self Regulating Heating Cable has two parallel conductors or bus wires extruded in a polymer core. The core's resistance changes porportionally with temperature.

The key to understanding Self-regulating cable is the output adjusts proportionally to the cable sheath temperature not the temperature of the pipe heated.

There is no direct feed back for the pipe temperature. Most self-regulating cables are designed to give their rated wattage at 50 degrees F. The wattage output willexceed the rated wattage when the cable temperature is below 50 degrees and the lower the cable temperature the larger this wattage i.e. amperage is. INRUSH!! A high start up current is the result. Tight temperature control is also more difficult with self-regulating cable, because the wattage output is always changing seeking 50 degrees F on the cable not the pipe or fluid in the pipe.

Self-regulating cable works quite well for freeze protection applications. Freeze protection and low temperature applications that do not require very tight control. The inrush can be considered on the design of wiring and breakers, and there are some other cost savings to consider. A thermostat is recommended for most applications. However, when there are several very short runs or several pipe size changes one ambient thermostat can save on a job.

The semi-conductive core contains a graphite network, which allows electricity to flow from one bus wire to the other. When the core is dense and colder, there are many paths for electricity to take through the graphite network, producing more heat.

Since the core material expands as it heats, the graphite network is elongated, disrupting some of the paths. More and more paths are disrupted as heating continues until the system reaches self-controlled thermal stability. When the core material cools it contracts, reconnecting some of the electrical paths in the graphite network, and more equivalent heat is produced.

This temperature response occurs independently at each point along the heater. If an externally produced high temperature occurs next to a low temperature in the cable, each section of heating cable will adjust its own heat output in relation to its own local requirements.

Advantages:

Cut to fit in the field.

Possible lower operating cost.

Possible lower installation cost.

Wide variety of wattages

Most tolerant to overlapping

Low Cost

Disadvantages:

High start-up currents

Difficult to precisely control temperature

Not well suited for procsss control

Low design temperatures

Constant Wattage Cable is made up with two parallel conductors or wires. These wires have a heater wire wrapped around and connected in approximately 2-foot intervals in parallel. This design provides constant wattage output or a uniform output all along its length. The heater wires are designed such that if any section of cable should fail the rest of the heater would continue to operate without change.

Constant wattage cable should NOT be overlaped. The effect of double the wattage where the cable crosses will cause high temp failures.

The constant wattage output makes maintaining higher and more accurate process temperatures easier. This cable is well suited for freeze protection and many low temp process control applications.

This cable can be cut in the field. When terminated the last 2-foot heater section becomes a cold sections "unheated". This provides an unheated section of cable to penetrate the insulation, enter the junction box and make up power connections. Constant Wattage Cable needs a thermostat on each pipe and each pipe size in order to maintain accurate temperature control.

Advantages:

Cut to fit in the field.

Easily controlled

Built in cold length at every power connection

Wide variety of wattage outputs

Low cost

480 Volt Cable available

Design Temperatures up to 500° F

Disadvantages:

Requires pipe sensing thermostats

CANNOT be overlaped

Heating Cable ~ Heat Trace

Heating cable is also referred to as heating tape and heat trace cable amongst the industry. Heating cable is used for a wide range of applications including pipe tracing, freeze protection, viscosity control, temperature process maintenance, roof and gutter, and much more. There are two main types of Heating Cables, Self Regulating and Constant Wattage.

Self Regulating Heating Cable products are used for freeze protection and process temperature maintenance for a wide range of industrial, commercial and residential applications. These industrial heaters are used to maintain the working temperature of pipes, fittings, valves, tanks and process equipment. Heat Trace cables regulate their heat output in response to changes in temperature. Self regulating heat trace cable can be overlapped and cut to length without loss of heat. It is ideally suited to freeze protection applications and snow melting but can be used in process applications as well. Self-Regulating / Self-Limiting heating cable automatically adjusts heat output based on surface temperature. Ideal for freeze protection and low temperature process maintenance. Self Regulating cable has advantages that is can be overlapped and cut to length without any heating loss on the cable. And In some caes can be used without control, though using a thermostat is always the suggested method fro turning the cable on and off.

Constant Wattage Heating Cables are ideally suited for applications where a particular watt density is required at all times. The heater element consists of a nichrome wire wrapped around parallel, insulated buss wires. Constant wattage cables are flexible, can be cut-to- length in the field, and are manufactured for use on voltages from 120 to 480V. Although not suited for overlapping, its constant output makes it an ideal choice for higher temperature applications where higher watt densities are required. Constant Wattage Cables are Equipped with a ground braid and can have an optional FEP jacket. Constant-Wattage heat trace provides precise and constant temperatures up to 500oF (260oC). Ideal for a wide range of applications. Constant wattage cable can be cut to length but there will then be a cold spot (unheated length) of cable that must be managed when you splice the cable together. Constant wattage cable must not be overlapped as it will over heat where the cable comes in contact with itself.

The theory behind heat trace is to replace the heat loss from a pipe into the space it travels through. A heat loss calculation is done and the result is a watts per foot of heat loss. To maintain a pipe temperature, the cable must equal or be greater than the heat loss. Heating cable is not good for actually heating up the pipe. It may work in unique applications, but in general it is for pipe temperature maintenance. Pipe trace cable can be used to keep down condensation in pipes when moving solids like flour where water creates a problem.

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