Which statement is correct about branch line heat tracing requirements?

• A. It is not required to be listed for branch line use.
• B. It must be specifically listed for branch line use.
• C. It may be used on branch lines without listing if approved.
• D. It is prohibited on branch lines.

Answer: (B)

Branch-line heat tracing is used to prevent freezing of water-filled lines in unheated spaces, and the equipment must be evaluated for that exact service. The requirement is that any heat tracing installed on a branch line be specifically listed for branch-line use. This listing comes from a recognized testing authority and confirms that the tracing, its controls, and installation practices are suitable for the environment and operating conditions of branch lines. Because of that, using heat tracing that isn’t listed for branch-line service isn’t permitted, and there isn’t an approved workaround that bypasses the listing. Listing ensures safety, compatibility, and reliable performance in preventing freezing.