IEEE C37.20.7 established the following performance ratings that must be listed on the apparatus rating label:

• Accessibility 
  • Type (example – Type 2B) 
    • Type 1 (Arc-resistant functionality in the front of the equipment only) 
    • Type 2 (Arc-resistant functionality in the front, rear and sides of the equipment only)
  • Optional accessibility type performance features (accessibility type suffixes)
    • “A” suffix (Arc-resistant provided all enclosure doors and covers are closed and secured) 
    • “B” suffix (Arc-resistant provided all enclosure doors and covers are closed and secured; except control/auxiliary compartment doors which can remain open)
    • “C” suffix (Arc-resistant functionality in compartments adjacent to the compartment in which the arc occurs). This suffix isn"t applicable for metal-enclosed low voltage switchgear. IEEE C37.20.7 – 2007 states that the “C” suffix designation isn"t applicable to equipment using open bus or open frame construction. All metal-enclosed low voltage switchgear uses an open bus design. · 
    • “D” suffix (A modification of Type 1 in which one or more of the enclosure surfaces is excluded from the arc-resistant category. For example, Type 1D-SR would indicate a design which arc-resistant functionality on the front and right side only, with the rear and left side considered inaccessible to personnel). 
• Maximum internal arcing short-circuit current 
• Maximum system voltage 
• Maximum arcing duration