Material Decisions: Choosing the Right Fastener for Hazardous Locations

Contractors often are required to select electrical equipment, such as 
enclosures, based on the environmental hazards any particular 
application might pose. The labeling system established by the National 
Electrical Manufacturers Association (NEMA) offers assurance that a NEMA
 4 enclosure, for example, has been tested and proven to be watertight. 
Selecting the right cable fasteners for such hazardous installations, 
however, can be a less-clear process. Thomas & Betts

Chuck Ross

Contractors often are required to select electrical equipment, such as enclosures, based on the environmental hazards any particular application might pose. The labeling system established by the National Electrical Manufacturers Association (NEMA) offers assurance that a NEMA 4 enclosure, for example, has been tested and proven to be watertight. Selecting the right cable fasteners for such hazardous installations, however, can be a less-clear process.

It’s not that there aren’t sufficient fastener options available to meet these applications’ needs – contractors have a wide variety of products choose from. However, without a NEMA-like rating system, contractors selecting fasteners for use in harsh settings need to understand how that environment might affect the material used to manufacture these products.

For example, many cable-tie products incorporate some form of nylon, but not all nylon formulations perform well under long-term exposure to UV radiation – in other words, sunlight. So, over a period of time in an outdoor setting, these ties could end up breaking apart. Weather-resistant polypropylene offerings provide a good alternative in such outdoor locations – unless, that is, high tensile strength also is a requirement. In that case, stainless steel ties might be the most suitable choice. Although stainless steel ties can be more expensive, they are also the strongest and among the least likely to degrade outdoors.

Other environmental and performance characteristics to consider, in addition to UV exposure and strength, include the temperature extremes, the need for flame retardance and/or low smoke production, and whether resistance to specific chemicals present at the location needs to be addressed. Manufacturers may provide tables that can help contractors identify the appropriate selection. However, contractors also might want to reach out to their distributor or manufacturer’s technical experts to confirm the best option in difficult environmental settings.


Photo courtesy of Thomas & Betts