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Mineral Insulated Wiring vs Polymeric Alternatives

San Francisco Skyline with Dramatic Clouds at Sunrise, California, USA

No Smoke, No Fire is Key to Building Safety

During a fire emergency, it’s critical to reduce the contribution of smoke, flames or fire. However, some fire protection systems, unlike nVent PYROTENAX mineral insulated cable, can actually give off smoke and combustible gasses under fire conditions. 

Some other cables are designed using organic materials for insulation. While these fire proof cables can meet code and are preferred by some contractors, there are also problems that can arise during a fire emergency.

Problems with Polymeric Design 

If these cables are installed in an enclosed environment (such as conduit), they may have insufficient oxygen to allow the burning off of volatile gas.

These gases can attack the standard copper in these cables, causing it to lose most of its strength which can lead to damage and breakage.

nVent PYROTENAX MI cables have a full 30 year warranty. The standard warranty for other cables is usually only up to two years.




Other Cables 


YES (30 Years)

YES  (1 to 2 Years)

Inorganic Construction



UL/ULC Fire-Rated



Full Free Air Rated



Broad Distribution



Trade/Skill Sensitivity



Space Required



Ideal for Retrofits 



Mechanical Strength (Ability to withstand a blow, falling concrete, etc.) 



fire building protection

Fire-Rated Wiring vs. Concrete Construction

cable amapacity

Mineral Insulated Wiring for Electrical Modernization

nVent PYROTENAX Fire-Rated Wiring Specifications on MasterSpec® Powered by Deltek SpecPoint®

nVent PYROTENAX MasterSpec

nVent PYROTENAX MI two-hour fire-rated wiring cables meet the most stringent fire testing standards for safety in buildings and infrastructure. They ensure safe operation of critical emergency circuits under fire conditions – which is essential for safe evacuation and to allow firefighters to continue their efforts during an emergency.

Download, edit and integrate the individual specification sections for your project.

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Download Our ISO 9001 Certified Laboratory Report

Big fire in the building

Did you know: Some UL 2196 / ULC-S139 Listed fire-rated cables produce toxic and/or combustible smoke and gases when exposed to typical building fire temperatures.

An ISO 9001 certified and a nationally recognized third party laboratory conducted a series of experiments to explore and to answer these questions and more.

Get the facts, and download our report today. 

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An urban electrical contractor chose mineral insulated (MI) 2 hour fire-rated cable to protect this building’s emergency electrical equipment in New York City. The fire resistant wire saves up to 80% of space, compared to conventional conduit and wire systems. See how the entire mineral insulated cable system was installed in this case study.