Current through Register Vol. XLI, No. 25, June 21, 2024
Section 36-48-9 - Disconnecting Devices9.1. The section power center shall be equipped with a main disconnecting device installed to de-energize the primary of all transformers supplying high-voltage power when the device is in the open position. The high-voltage trailing cable extending to section equipment shall be equipped with a disconnecting device installed to de-energize the trailing cable when the device is in the open position. 9.1.a. The power center must be equipped with an externally accessible emergency stop switch hard wired into the incoming ground-wire monitor circuit that de-energizes the incoming high-voltage power circuit to the section power center in the event of an emergency.9.2. The compartment for the disconnect device and the compartment(s) that provide access to energized conductors or parts shall be provided with caution label(s) to warn miners against entering the compartment(s) before de-energizing and grounding the high-voltage circuits and before any capacitor storage devices located within the compartment(s) have been discharged and grounded. A grounding device for discharging capacitor storage devices shall be provided and stored in a dry location. A label shall be installed and maintained at the grounding device storage location to readily identify its location.9.3. Disconnecting devices shall be rated for the maximum phase-to-phase voltage of the circuit in which they are installed, and shall be rated for the full load current of the circuit that is supplied power through the device.9.4. Each disconnecting device shall be designed, installed and maintained so that: 9.4.a. It can be determined by visual observation that the contacts are open without removing any cover;9.4.b. All load power conductors can be grounded when the device is in the "open" position; and9.4.c. The device can be locked in the "open" position.9.4.d. If a cable coupler is used as the disconnecting device, a clearly identified grounding receptacle must be provided. The conductors in the high-voltage cable must be connected to the grounded frame of the metallic power center enclosure by means of the grounding receptacle. A lockout device will be provided to lock the cable coupler to the grounding receptacle. A dust cover shall be placed on the power receptacle from which the cable was disconnected.9.5. Disconnecting devices, except those installed in explosion-proof enclosures, shall be capable of interrupting the full-load current of the circuit or designed and installed to cause the current to be interrupted automatically prior to the opening of the contacts of the device.9.6. Disconnecting devices installed in explosion-proof enclosures shall be maintained in accordance with the approval documentation.