rating of Critical branch feeders

[mshields]

Is there anywhere in Article 517 requiring 1 hour rating of Critical feeders ala the requirement for Article 700 feeders?

 

[barbeer]

By the definitions in 517, life safety and critical branches are both subsystems of the emergency system..........only life safety has a reference to art. 700.
If you would call this "essential electric system" the it tells you to meet req. for 700.(517.26)

Unless you deal with all this everyday it can be confusing.

 

[steve66]

only life safety has a reference to art. 700.

517.26 references article 700 for the essential electrical system, which includes the critical and equipment branch as well as the life safety branch.