TABLE OF CONTENTS It is the intent of this chapter to provide information and data that is often needed, but perhaps is a little bit outside of the mainstream day-to-day information required by the electrical design professional. In some cases, it represents emerging practices resulting from technological, code, or regulatory changes. In other cases, it represents popular misapplication of established codes or other requirements that are sometimes misunderstood. And finally, it may simply be information that is needed but less frequently encountered.
Mineral-insulated (MI) cable has been around for a long time and is a cable of the highest thermal capacity and integrity. Historically, because of these qualities, and the premium cost associated with these qualities, its applications have been limited. This has bred a lack of familiarity familiarity and reluctance to use this cable in many applications.
The National Electrical Code and many state and local code and regulatory requirements are changing this. Because this type of cable has a 2-h fire-resistive rating as approved by the Underwriters Laboratories (UL), this type of cable is gaining popularity in meeting the latest code mandates.
When reviewed at a microscopic level, as compared with conventional construction, using this type of cable for 1-h and 2-h fire-resistive construction, it becomes a cost-effective solution in complying with these code mandates. It also requires considerably less space (in the order of 97 percent less space) in meeting these requirements, which makes it particularly amenable to renovation/retrofit projects.
