New York State Master Electrician Practice Exam

Which of the following is not a characteristic of non-metallic sheathed cable?

1. Water resistance

2. Flexibility

3. Low fire hazard

4. High voltage capacity

The correct answer is: High voltage capacity

Non-metallic sheathed cable, commonly known as NM cable or Romex, is designed primarily for residential wiring and has specific characteristics that define its use. High voltage capacity is not a characteristic associated with non-metallic sheathed cable. This type of cable is typically rated for lower voltage applications, such as the standard 120/240 volt systems found in most homes. In contrast to high voltage capacity, non-metallic sheathed cable is designed to be flexible, allowing for easy installation in various residential settings. Its water resistance is also a valued trait, providing some protection against moisture in typical environments where it is installed. Additionally, the materials used in non-metallic sheathed cable contribute to a lower fire hazard compared to other types of cable, making it a safer choice in residential applications. Best practices dictate limiting the use of NM cable in situations where high voltage or extreme conditions are present, which further emphasizes why high voltage capacity is not a suitable characteristic for this type of cable.