High-Temp Wire

How Hot Can High-Temp Wire Handle? Let’s Find Out

Understanding High-Temperature Wires

Anyone can install cable in environments with high ambient temperatures and high conditions. But how high can temp wire handle? Choosing the right cable for the right environmental conditions is vital to ensure that your cable’s lifespan won’t be affected. The use of hot temp wire and cable products outside their designated temperature range may result in premature, and more often than not, expensive service failures. 

How hot can wires get?

The research from CDA has shown that temperatures of open wires located in attics can get dangerously close to 194 degrees Fahrenheit limit. If these wires are buried in the attic’s insulation, arranged in tight bundles, or pass through light fixtures, they will get even hotter compared to when they’re out in open air.

Is it normal for electrical wires to get warm?

While it’s somehow normal for cords to get warm for appliances that use significant power, like, for example, a motor or a heater. If this cord becomes hot, it’s most likely exceeding its limit for its cord rating. Do not use the device or appliance if its cord gets hot. This is a high risk for fire.

What is High-Temp Wire?

If a wire has a temperature rating of 125 degrees celsius or higher, this is what we call a high-temp wire (high temperature wire). However, high-temperature may also refer to temperature as low as 90 degrees celsius. High-temperature wires may either be multi-conductor or single-conductor. They usually consist of conductors (compper, tinned, annealed, or nickel-coated) and an insulator. High-temp wires can also have additional protective jackets made out of fiberglass or k-fibers. 


The 2 most important components to make sure that high-temp wires are suitable for application are: ampacity and temperature rating.


Temperature ratings are explained as a maximum continuous temperature that a wire can handle in its entire lifespan. While ampacity is the maximum current that an insulated conductor can safely handle without exceeding its insulation capacity, and jacket temp limits. 

How High Can Temp Wire Handle?

There are a variety of high temp wires that are available depending on several factors and applications. Due to the large range of temperature ratings and applications available for high-temperature wires, there are a lot of different agency approvals available. High-temperature wires can be Recognized per UL Listed per UL83A, UL 758, or meet CSA standards. Please refer to the table below for reference:


UL 758 and/or CSA standards.

Trade Name Description Temperature Voltage Size UL Styles,

CSA Standards

EPDM Ethylene proplyene diene monomer 125ºC to 150ºC 600 V 18 AWG to

4/0 AWG

UL 3284,

UL 3374;

CSA 1254

SRK Silicone rubber with K-fiber jacket 200ºC 600 V 18 AWG to

4/0 AWG

UL 3071, UL3074,

UL 3075, UL 3125,

UL 3126;

CSA SEW-2 3410

TGGT PTFE/glass 250ºC 600 V 24 AWG to 4/0 AWG UL 5256,

UL 5196

EPDM Ethylene proplyene diene monomer 125ºC to 150ºC 600 V 18 AWG to

4/0 AWG

UL 3284,


CSA 1254

Table 1: Common UL Style High-temperature Wire Types

In addition to the AWM high-temperature wires, Table 2 provides examples of UL Listed high-temperature wires per UL 83A.

UL Listed Name Description Temperature Conductor Metal Size Voltage
FEP Fluorinated ethylene propylene 90ºC (200ºC special applications) Soft-annealed copper 14 AWG to


600 V
PFA Perfluoroalkoxy 90ºC (200ºC special applications) Soft-annealed copper 14 AWG to

4/0 AWG

600 V
TEE Tetrafluoroethylene 250ºC Nickel-coated copper or nickel-base alloy 14 AWG to

4/0 AWG

600 V
ZW Ethylene Tetrafluoroethylene 90ºC (200ºC special applications) Soft-annealed copper 14 AWG to


600 V



For specific projects and applications that require sustaining a specific temperature, extreme resistance, or heat, special cables like high-temp wires are essential. Don’t forget that in order to prevent damages, accidents, or replacements, make sure to choose the right product you need. If you cannot decide or find it hard to choose, simply reach out and we’re ready to help. 

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