High Temperature Cable: SRML, TGGT, FEP, MGT Cables

This article discusses some of the most popular high temperature cables found today. It covers both insulating and jacketing compounds as well as common usages for these specialty electrical products.

High temperature cables are required in various types of applications in today’s world. Many industries, both commercial and industrial, frequently depend on high temp cables for power, control and instrumentation circuits. They run motors, fire alarm systems, appliances, furnaces and all types of electrical equipment when temperatures can rise over normal operating levels.

Here are the most common high temperature products found today.

SRML or SFF-2 – SRML stands for Silicone Rubber Motor Lead Wire. It is rated at 150C. Many times it will be called out as SFF-2. It is a 600 volt single conductor product that is used in motor leads and fixtures. It uses a tinned copper stranded conductor covered with a silicone rubber and then a fiberglass braid is applied over the rubber insulation. It can be found in both circuit and power sizes and in a variety of colors.

FEP – FEP stands for Fluorinated Ethylene Propylene. FEP was invented by DuPont and it is used quite frequently in high temp applications. FEP can be found in all types of voltages and both stranded and solid conductors. The most common is stranded tinned copper version in 600 volts manufactured both circuit and power sizes. FEP is used in all types of appliances and electrical components including igniters and thermocouples. It provides excellent resistance to gas, oil, moisture and acids. It is also available in a variety of colors to the user.

TGGT – This single conductor 600V high temp cable features a stranded nickel coated copper conductor. The insulation is a TFE Teflon/ceramic tape covered by another TFE Teflon impregnated glass braid with a flame, heat and abrasion resistant finish. TGGT is rated at 250C making it a good choice in many industrial applications such as the internal wiring of heating and cooking equipment. TGGT only is available in a tan color since it can’t be dyed like FEP or SRML.

MGT or MG – MGT, or MG cable, is a 27% nickel coated copper conductor. It is insulated with glass reinforced mica tapes and then a high temperature overall fiberglass braid is added. This allows MGT cable to reach 450C or as high as 538C in a non-UL application. This single conductor product is 600V and can be found in very high temperature environments such as iron mills, steel mills and glass plants. Like TGGT, this product only comes in a tan color.

CIC – CIC stands for Circuit Integrity Cable. This item can cover a wide range of high temperature products in both single and multi-conductor. Circuit integrity cables are made in multiple variations but most use fluoropolymers such as FEP and multiple layers of a mica glass braid to reach very high temperatures. Some of these cables can maintain operations of over 1000 degrees Celsius at more than an hour. These can be vital when people are involved in terms of safety. These cables can be very expensive but are ideal for critical circuits requiring electrical integrity in the event of a fire.

It is worth mentioning that most of these high temperature items can be manufactured in many variations including multi-conductor on special constructions.