Cartridge Heaters

Cartridge Heaters | Indelex Heating

Our product selector can guide you, step-by-step, through the process of specifying the right cartridge heater for your needs

Cartridge Heaters

INDELEX cartridge heaters are built using premium, durable materials and backed by our commitment to outstanding quality and service. Engineered to satisfy the broadest range of applications, our cartridge heaters provide the highest possible heat transfer rates, uniform temperatures, and operational reliability.

Our high watt density cartridge heaters comprise a nichrome resistance wire, wound around a magnesium oxide (MgO) core, inserted in a high temperature alloy sheath. The remaining space is then filled with a high purity MgO insulation powder and the heater is swaged to a particular diameter. This process of swaging results in increased thermal conductivity, dielectric strength, and vibration resistance. The greatly increased strength of the heater ensures a long, high-performance lifespan and reduces critical downtime.

INDELEX high density cartridge heaters are suitable for operating temperatures up to 760°C and are available in more than 60 metric and imperial diameters, up to 1¼” or 25mm.

 lengths up to 3000mm
up to 10,000 Watts
 up to 480 volts
 watt density of up to 260 watts per square inch

Square, rectangular and split sheath profiles are also available.

All our heaters are CE marked, with UL component recognition available on request. With additional testing our cartridge heaters can also be certified for use in vacuum atmospheres.

For non-standard applications all options can be tailored using our custom heater design service.

ATEX certified versions are available for use in hazardous areas.

Sheath Materials

Cartridge heaters come in 304 stainless steel as standard, but a wide range of alternatives are available, including:

  • 316 Stainless Steel
  • 321 Stainless Steel
  • Incoloy 800
  • Incoloy 825
  • Inconel
  • Brass


selection of cylindrical, square, rectangular and split sheath cartridge heater profiles

Standard (cylindrical) type cartridge heaters are available in the following diameters:

Imperial:1/8″   1/4″   5/16″   3/8″   7/16″   1/2″   9/16″   5/8″   3/4″   1″   1+1/4″
Metric:4mm   6mm   6.5mm   8mm   10mm   12mm   12.5mm   14mm   15mm   16mm   18mm   20mm   25mm

Square section cartridge heaters are available in the following dimensions:

Imperial: 1/8″ x 1/8″   1/4″ x 1/4″   3/8″ x 3/8″   1/2″ x 1/2″   5/8″ x 5/8″
Metric:4.5mm   6mm   8mm   10mm

Rectangular section cartridge heaters are available in the following dimensions:

Imperial: 1/8″ x 1/4″   1/8″ x 3/8″   1/4″ x 5/8″   1/4″ x 1″
Metric:6mm  x  12mm

Split sheath cartridge heaters are available in the following diameters:

Imperial: 1/8″   1/4″   5/16″   3/8″   7/16″   1/2″   9/16″   5/8″   3/4″   1″
Metric:4mm   6mm   6.5mm   8mm   10mm   12mm   12.5mm   14mm   15mm   16mm   18mm   20mm   25mm

For complete information on nominal diameters versus actual diameters, as well as tolerances, please view our cartridge heater data sheet.

For special applications we can offer closer tolerances than the standard, using a process of centreless grinding. Please ask our sales team for details.

Terminal Types

The standard termination is Type A, which comprises two straight exit glass fibre leads. The most common termination types are shown below with a full listing available on our cartridge heater data sheet. All terminal types can be fitted straight or at 90⁰ to the heater.

  • Glassfibre leads
  • Silicon rubber leads
  • PTFE leads
  • Stud terminals
  • Mounted plugs
  • Silicon rubber cables
  • Flexible conduit
  • Armour wire braid
  • Terminal boxes
  • Nickel pins
  • Heat resistant sleeving
  • Fish-spine beaded leads

Cartridge Heaters with Built-In Thermocouples

Cartridge heaters with internal thermocouples (one or more) are available in any common calibration.

Cartridge Heater with Built-In Thermocouple | Indelex Heating
Internal Thermocouple:Cartridge heaters can be supplied with built in thermocouples in a number of styles:

1) With the junction located in the heater core to monitor the internal temperature of the heater.
2) With the junction located adjacent to the inside heater sheath (a ½” unheated section is required)
3) With the junction embedded in a special end disc.

Special Features

As well as cartridge heaters with internal thermocouples, a wide array of special features are available, including: IP terminal boxes, zoned heaters, distributed wattage, formed heaters, finned heaters, and many others. Please contact us for information on all the options available.

Cartridge Heater with Built-In RTD's, Thermostats or Fuses | Indelex Heating
Cartridge heaters can have built in RTDs, thermostats, or fuses, normally located in an unheated section at the lead end or disk end, and with separate leads, to enable use of external temperature or power controls. Please contact our sales team for details and parameters.
Cartridge Heater with IP Terminal Box | Indelex Heating
Terminal Boxes:Metal terminal boxes can be fitted, with up to IP67 rating. Please state any size restriction, and preferred gland location.
Formed Cartridge Heater with Unheated Lead Exit | Indelex Heating
Formed Heaters:In extreme ambient conditions, heaters can have the lead exit removed from the hot or wet area by use of a welded right angle tube, which can be of any length necessary.
Cartridge Heaters with Quick Disconnect Plug | Indelex Heating
Quick Connect:Heaters can have quick disconnect plugs of various types mounted at the lead end, where easy removal and replacement is necessary.
Finned Cartridge Heater | Indelex Heating
Finned Heaters:Cartridge heaters can be fitted with helical fins, enabling them to be used in air heating applications.
Standard cartridge heaters have their internal resistance wire evenly wound along the length of the sheath, giving uniform heat output over the inserted part. However, this is not always ideal, and in some applications, variations from the norm are desirable. Some of the available options are:
Unheated Sections:Cartridge heaters can be supplied with unheated sections at any desired location along their length. Unheated sections are most commonly used in immersion applications, or where special lead systems cannot be exposed to higher temperatures.
Distributed Wattage:Cartridge heaters can be supplied with distributed wattage by modifying the coil pitch along the length of the heater. Used in applications that require more wattage in some areas to maintain temperature uniformity, or to modify process conditions.
Multi-Circuit Heaters:Multi-circuit heaters can have several independent windings, allowing the heaters to be used on three phase supplies, on dual voltage, or to have independently controlled heat zones. In larger diameters, a thermocouple per zone can also be incorporated

Typical Cartridge Heater Applications

Cartridge heaters are most often used for the localised heating of metal parts, such as: moulds, platens, sealing bars, shaping dies, marking appliances, and cutting tools. Their versatility means they can also be used for air, gas, and liquid heating where space is limited. Typical cartridge heater applications include:

  • Packaging equipment
  • Heat sealing
  • Plastic mould tools
  • Food Processing
  • Laminating presses
  • Plastic extruder heads
  • Medical equipment
  • Scientific equipment
  • Hot runner moulds and stamping dies
  • Sterilizers
  • Anti-condensation
  • Washing systems
  • Labelling
  • Bonding
  • Etching
  • Vacuum forming


Backed by more than 30 years of experience in process heating solutions, INDELEX supplied cartridge heaters are widely used across an extensive range of industries:

  • Medical Devices
  • Breweries and Distilleries
  • Laboratories
  • Appliance manufacturing
  • Cosmetics production
  • Food processing
  • Meat and Dairy Processing
  • Pharmaceuticals
  • Catering
  • Chemical production
  • Glass manufacturing
  • Synthetic fibre production
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