Section 690-334 - Mandatory safety components of electrical equipment(a) Requirement.--Low-voltage, medium-voltage and high-voltage resistance ground systems shall have ground wire monitors to continuously monitor the continuity of the grounding circuits to the equipment affected, except for: (1) Low-voltage and medium-voltage circuits supplying power to longwall illumination systems.(2) Low-voltage and medium-voltage stationary equipment installed in accordance with all of the following: (i) The equipment is permanently installed at a fixed location.(ii) All load components are securely attached to a common metallic frame or structure.(iii) Each component of the equipment is grounded by two independent equipment safety grounding, each sized appropriately.(iv) At least one of the equipment safety ground conductors to each component is visible for its entire length. High-voltage resistance grounded systems shall have ground wire monitors to continuously monitor the continuity of the grounding circuits. All ground wire monitors shall be designed and constructed to be failsafe.(b) Study.--The mining industry shall initiate a study to enhance the safety of underground direct-current machine cables. The program shall include an evaluation of ground wire monitors for use on all direct-current equipment. The program shall include laboratory and underground testing. The test results shall be documented and presented to the Board of Coal Mine Safety no later than 365 days after the effective date of this act for action by the board.(c) Additional study.--The mining industry shall initiate a study to enhance the safety of underground cables. The program shall include an evaluation of metallic shielded cable, nonmetallic shielded cable and more sensitive ground fault limiting and detection. The program shall include laboratory and underground testing. The results shall be documented and presented to the Board of Coal Mine Safety no later than 365 days after the effective date of this act for action by the board.(d) Plugs.--If plugs are used on any cable in a mine, the plugs must be interlocked.2008, July 7, P.L. 654, No. 55, §334, effective in 180 days [ 1/5/2009].