Cartridge Heaters, Pencil Heaters, Rod Heaters

The Big Chief Cartridge Heater is the top-of-the-line, high-density cartridge heater. Our heater is so highly compacted that it produces superior heat transfer, and the dielectric and physical strength necessary for long heater life and outstanding performance. Our heater is designed for high-temperature applications or where vibration occurs. Our heaters are available in 1/8″, 1/4″, 5/16″, 3/8″, 1/2″, 3/4″, 15/16″, 1″, and 1 1/4″ diameters in every imaginable length increment and hundreds of lead configurations. Our heaters are also available in the following metric diameters: 6.5mm, 8mm, 9.5mm, 10mm, 12mm, 12.5mm, 16mm, 18mm, 19mm, 20mm, and 25mm.

  • Nickel-chromium resistance wire precisely wound on magnesium oxide core.
  • The magnesium oxide is thoroughly compacted to a predetermined density. The density is very important, as it results in the best combination of high dielectric strength and efficient, fast heat transfer.
  • Stainless Steel is used as the standard sheath material on our cartridge heaters because it provides maximum protection against high-temperature oxidation and corrosion from a broad range of chemicals and atmospheres. The maximum Sheath Temperature is 1500°F.
  • Solid nickel conductor pins overlap the resistance wire inside the core. For crimped-on lead connections, mechanically crimped splices connect 12″ lead wires to solid nickel pins, insulated with fiberglass sleeving. Leadwire is TGGT, rated for 482°F. For swaged lead connections, hi-temp wires are internally connected to the resistance wire and protected by a hi-temp potting at the end of the heater.

Big Chief Cartridge Heater Spec Sheet PDF

Lead Configurations

IL Leads 2_1
Style “IL” Leads
Leads are internally connected in heater. Internally connected leads are used in applications where a high degree of flexing exists, or the leads must be sharply adjacent to the heater without exposing or breaking the conductor.LEADWIRE RATED FOR 850°F/450°C IS NORMALLY SUPPLIED.
Style-SSA – Stainless Steel Conduit Stainless steel conduit is designed to prevent damage to the leads from abrasion against sharp edges. rasa-heater Style-RASA – Right Angle Stainless Steel Conduit Right angle stainless steel conduit is used where space is limited and to protect the leads from abrasion.
Style-SCA – Stainless Steel Conduit with Copper Coupler Stainless steel conduit with copper coupler is the same as style SSA except with a copper coupler that overlaps heater sheath. RACA Leads 2 Style-RACA – Stainless Steel Conduit with Copper Coupler at Right Angle Same as style RASA except with 90° copper coupler that overlaps heater sheath.
SSB Leads 2A Style-SSB – Stainless Steel Metal Braid Stainless steel metal braid is designed to prevent damage to the leads from abrasion. It is more flexible than stainless steel conduit. RASB Leads 2 Style-RASB – Right Angle Stainless Steel Metal Braid Right Angle stainless steel metal braid is the same as style SSB except at a right angle.
RAL 4 Style RAL – Right angle hi-temp fiberglass internally connected leads.


Threaded Fittings


Style-TF Pipe threaded fittings are available in brass or stainless steel and are attached leak-tight to the heater sheath. All diameters 1/4″ and up.

Cartridge Heater with Internal Thermocouple



A cartridge heater with an internal thermocouple is for applications where monitoring the internal temperature of the heater is necessary as over-heat protection or where material flow is close to the heater sheath as in plastic molding. 12″ high temperature (850°F/450°C) leads are standard. When ordering, specify whether the junction is grounded or ungrounded and what type of thermocouple needed. The standard position for either a grounded or ungrounded junction is at the bottom.

Stainless steel flange welded directly to heater sheath. Fiberglass insulated leadwires are the standard. Other flange sizes and hole patterns are available upon request.

Diameter Inches Flange Size Inches
1/4, 3/8, 1/2 FS 1 3/4 0.144
1/4, 3/8, 1/2, 5/8, 3/4 FM 1 1/2 1 1/ 8 0.156
5/8, 3/4, 1 FL 2 1 1/2 0.201

Maxiwatt Expan Split Sheath Cartridge Heater

The expandable cartridge heater solves two major problems associated with conventional cartridge heaters – poor durability and proper fit. The expandable cartridge heater will expand in the hole and will make better contact against the walls during heating, providing uniform heating along the complete length of the heater, better durability, and longer heater life. After cooling, the heater can be easily removed – meaning no more drilling, hammering, or destruction of heaters being removed from the holes. Expan heaters can be made with various lead terminations, threaded fittings, built-in thermocouples, and flanges.

Cartridge Heater Specifications Maxi-Watt-Split-Sheath-Threaded-fitting1 Maxi-Watt-Split-Sheath-Rt-Angle1 Maxi-Watt-Split-Sheath-IL-leads2
Maxi-Watt-Split-Sheath-IL-leads1 Maxi-Watt-Split-Sheath-Flange1
Nominal Diameter 1/4″ 5/16″ 3/8″ 1/2″ 5/8″ 11/16″ 3/4″ 7/8″ 1″ 6.5mm 8mm 10mm 12.5mm 16mm 20mm
Actual Diameter +/- .002 0.246 0.309 0.371 0.496 0.621 0.683 0.746 0.871 0.996 0.252 0.312 0.391 0.489 0.627 0.784
Maximum Voltage 240 240 240 240 480 480 480 480 480 240 240 240 240 480 480
Maximum Amperage 4.2 6.0 6.5 10.5 22.0 22.0 22.0 22.0 25.0 4.0 6.0 6.0 10.5 22.0 22.0
Wattage Tolerance +5% – 10% of rated wattage
Length Tolerance +/- 3% of the length
Camber Tolerance Up to 12″ long: .010 per foot Over 12″ long: .015 per foot
Watt Density Total Wattage: Diameter x 3.14 x heated length

Factors for Longer Cartridge Heater Life

  • Do not exceed recommended maximum watt density specified for heater size.
  • The heater sheath must fit properly into the machined hole. A tight fit is critical.
  • Protect the heater from contaminants such as oil, grease, and vapors.
  • Install adequate KW to accomplish workload and make up for heat losses.
watt density chart
  • Nominal Diameter
  • Overall Sheath Length
  • Lead Length
  • Termination Type
  • Voltage
  • Wattage
  • Special Modifications

Special Modifications

  • Distributed Wattage – resistance windings can be concentrated in specific areas of the heater for localized heat distribution.
  • Centerless Grinding – precision grinding of the heater sheath provides tighter diameter tolerances when required.
  • Teflon Coating – Teflon coating can be provided on a heater sheath for applications requiring chemical resistance.
  • Ground Leadwire – separate color-coded ground wire can be provided if required.
  • Special Connectors – Various connectors for power leads can be supplied upon request.

Cartridge Heater Care & Maintenance

  • Store heaters in a dry area, especially during periods of high humidity.
  • Protect leads from abuse and abrasion.
  • Maintain temperature control and keep accessories in good working condition to obtain correct operating conditions.
  • All cartridge heaters have hygroscopic tendencies and can accumulate moisture in shipping and storage. Low heater insulation (less than 1 megohm) can be baked in an oven for several hours or started at low voltage to eliminate moisture.