New York State Master Electrician Practice Exam

Cables that are not suitable for use in riser and plenum spaces are classified under Class 2. This classification indicates that the cables meet specific criteria regarding their fire resistance and low smoke production, making them appropriate for certain installations but not for areas where higher safety standards are necessary, such as riser or plenum applications. Riser spaces often involve vertical pathways for cables, and plenum spaces are used for air circulation in heating and air conditioning systems. These areas require cables that have a higher flame spread rating and lower smoke generation characteristics to ensure safety and minimize risk in the event of a fire. Class 2 cables do not meet these stringent requirements, which is why they are designated as unsuitable for those spaces. This ensures compliance with safety regulations and building codes, focusing on the need for greater fire protection in sensitive areas.