Service equipment must legibly display which of the following?

Service equipment must legibly display the maximum available fault current because this information is critical for ensuring safety during maintenance and operation. The maximum available fault current indicates the highest level of electrical current that could potentially flow during a fault condition, such as a short circuit. Knowing this value is essential for selecting the appropriate protective devices, such as circuit breakers and fuses, that can adequately handle fault conditions without failing or compromising safety.

Having this information displayed helps ensure that anyone working with or around the equipment can assess the potential risks involved. It also assists in proper planning for protective measures and coordination with other elements of the electrical system. This transparency is a requirement in many electrical codes and standards, as it enhances the safety and reliability of electrical installations.

The other options, while they might be relevant for operational purposes or documentation, do not carry the same level of critical safety importance as the maximum available fault current, making that option the primary requirement for display on service equipment.