A disconnecting means has been installed for an ESS to disconnect it from its associated wiring systems. The disconnect is installed in a separate room from the ESS for accessibility. The handle of the disconnect is required to be ___.

• A. Lockable in the closed position
• B. Lockable in the open position
• C. Installed at no less than 8 feet above finished floor
• D. No locking requirements are necessary

Answer: (B)

The important idea is that the disconnect for an ESS must be lockable in the open position to support lockout and ensure the system stays de-energized during maintenance. When the disconnect is in a separate room for accessibility, a lock on the open handle lets authorized personnel keep the circuit open, preventing reenergizing until it’s safe to restore power. Locking it in the closed position wouldn’t reliably block energizing, and height requirements aren’t the controlling factor here. No locking is not acceptable for an ESS disconnect because that could allow unintended energizing during work.