{"data":{"id":"us-ky/krs-352.220","jurisdiction":"us-ky","citation":"KRS 352.220","heading":"Electricity in mines and surface installations.","body":"For purposes of this section, \"approved\" means that a device, apparatus, equipment,\nmachinery, or practice employed in the mining of coal has been approved by the\ncommissioner of the Department for Natural Resources or accepted by a nationally or\nfederally recognized testing laboratory or the Department of Labor Mine Safety and\nHealth Administration; \"suitable\" means a design, material, or installation that meets the\nrequirements of its intended use or that is accepted by a nationally or federally recognized\ntesting laboratory or the Department of Labor Mine Safety and Health Administration.\n(1) The following shall apply to underground installations:\n(a) Nonconductive or insulated materials shall be used when trailing cables or\nhigh voltage feeder cables are suspended;\n(b) Suitable circuit -interrupting devices shall be provided for all power circuits\nand equipment at the mine;\n(c) All power wires and cables shall be properly insulated and protected by proper\ninstallation or guarding;\n(d) Ground wires for circ uits shall have a total cross -sectional area of not less\nthan one-half (1/2) the power conductor;\n(e) Extra length or long trailing cables shall be spread out in long open loops or in\na figure-eight configuration on a clean, well rock-dusted floor where the cable\ncan be protected against mechanical injury, but cables suspended in long open\nloops shall be acceptable;\n(f) One (1) temporary splice may be made in any trailing cable. No temporary\nsplice shall be made in a trailing cable within twenty -five (25) f eet of the\nmachine except cable reel equipment. Splices in trailing cables shall be made\nin a workmanlike manner and shall be mechanically strong and well insulated.\nSplices made in cables shall provide continuity of all components;\n(g) Three-phase alternating-current circuits used underground shall contain either\na direct or derived neutral which shall be grounded through a suitable resistor\nat the power center, and a grounding circuit, originating at the grounded side\nof the grounding resistor, shall exte nd along with the power conductors and\nserve as a grounding conductor for the frames of all the electrical equipment\nsupplied power from that circuit;\n(h) The frames of hand -held electrically driven tools shall be properly grounded\nor double -insulated by d esign. The frames of all pumps shall be properly\ngrounded. Hand -held tools and all pumps shall be properly protected by\nsuitable fuses, circuit breakers, or other no less effective devices to provide\nthe minimum overload and shortcircuit protection required by the department;\n(i) All underground high -voltage transmission cables shall be installed only in\nregularly inspected air courses and haulageways, and shall be covered, buried,\nor placed so as to afford protection against damage, guarded where men\nregularly work under or pass under them unless they are six and one -half (6-\n1/2) feet or more above the floor or rail, securely anchored, properly insulated,\nand guarded at ends, and covered, insulated, or placed to prevent contact with\nother circuits. Undergro und high -voltage cables used in resistance grounded\nsystems shall be equipped with metallic shields around each power conductor,\nwith one (1) or more ground conductors having a total cross -sectional area of\nnot less than one -half (1/2) the power conductor,  and with an insulated\ninternal conductor not smaller than No. 10 (AWG) or an insulated external\nconductor not smaller than No. 8 (AWG) for the ground continuity check\ncircuit. All cables shall be suitable for the current and voltage and shall be\nproperly maintained;\n(j) Power circuits shall have suitable disconnecting devices and short -circuit\nprotective devices at or near the supply end of the circuit. Suitable\ndisconnecting devices shall be provided at the beginning of all branch circuits;\n(k) Underground transformer stations, battery charging stations, substations,\nrectifiers, and water pumps shall be housed in noncombustible structures or\nareas or be equipped with a suitable fire-suppression system.\n1. When a noncombustible structure or area is used, these installations\nshall be:\na. Ventilated with intake air that is coursed into a return air course or\nto the surface and that is not used to ventilate working places; or\nb. Ventilated with intake air that is monitored for carbon monoxide\nor smoke by an atmospheric monitoring system (AMS) installed\nand operated in a suitable manner. Monitoring of intake air\nventilating battery charging stations shall be done with sensors not\naffected by hydrogen; or\nc. Ventilated with intake air and equipped with sensors to monitor for\nheat, carbon monoxide, or smoke.\n2. The sensors used for monitoring shall de -energize power to the\ninstallation, activate a visual and audible alarm located outside of and on\nthe intake side of  the enclosure, and activate doors that will\nautomatically close when any of the following occurs:\na. The temperature in noncombustible structure reaches one hundred\nsixty-five (165) degrees Fahrenheit;\nb. The carbon monoxide concentration reaches ten (10)  parts per\nmillion above the ambient level for the area; or\nc. The optical density of smoke reaches 0.022 per meter.\n3. At least every thirty (30) days, sensors installed to monitor for carbon\nmonoxide shall be calibrated with a known concentration of carb on\nmonoxide and air sufficient to activate the closing door, or each smoke\nsensor shall be tested to determine that it functions correctly.\n4. When a fire suppression system is used, the installation shall be:\na. Ventilated with intake air that is coursed into a return air course or\nto the surface and that is not used to ventilate working places; or\nb. Ventilated with intake air that is monitored for carbon monoxide\nor smoke by an atmospheric monitoring system installed and\noperated in a suitable manner.\n5. All monitoring systems used to monitor intake air ventilating battery\ncharging stations under subparagraphs 1. and 4. of this paragraph shall\nbe done with sensors not affected by hydrogen.\n6. This paragraph shall not apply to:\na. Rectifiers and power cent ers with transformers that either are dry -\ntype or contain nonflammable liquid, if they are located at or near\nthe section and are moved as the working section advances or\nretreats;\nb. Submersible pumps;\nc. Permissible pumps, and associated permissible switchgear;\nd. Pumps located on or near the section that are moved as the\nworking section advances or retreats; or\ne. Small portable pumps. Underground stations containing\ntransformers or circuit breakers filled with flammable oil shall be\nprovided with door sills or their equivalent, which will confine the\noil if leakage or rupture occurs, and shall be of fireproof\nconstruction. Underground transformers purchased after June 16,\n1972, shall be air cooled or cooled with nonflammable liquid or\ninert gas. Portable  power centers, portable transformers, and\ndistribution centers which are essentially fireproof are not required\nto be placed on separate splits of air but shall be stationed in well\nventilated places outby the last open crosscuts;\n(l) Electrically powered  locomotives shall be provided with suitable electrical\nprotective devices;\n(m) Suitable firefighting equipment shall be located at strategic points along the\nbelt conveyor, and proper fire extinguishers shall be provided at the transfer\npoints. The commis sioner may prescribe any other safety measures for the\nprevention and combating of mine fires as they pertain to conveyor belts. Only\napproved flame resistant belting shall be taken into and used inside any mine,\nand all underground belt conveyors shall be  provided with slippage and\nsequence switches and with start and stop controls at intervals not to exceed\none thousand (1,000) feet. The controls shall be properly installed and\npositioned so as to be readily accessible;\n(n) Communication wires and cables shall be adequately insulated and protected\nby proper installation or guarding;\n(o) Telephone wires shall be provided with lightening arresters where the wires\nenter the mine and at the buildings on the surface;\n(p) Insulating mats shall be placed in front  of disconnecting devices and all\nelectrical installations where required;\n(q) Ground wires in trailing cables shall be tested weekly for open circuit and\nhigh resistance;\n(r) Power circuits in tipples, buildings, cleaning plants, etc., and all underground\nelectrical circuits shall be deenergized when not in use over a long period;\n(s) All underground power circuits and electrical equipment shall be de-energized\nbefore work is done on the circuits and equipment except when necessary for\ntroubleshooting or testing. When electrical work or major mechanical work is\nperformed, a suitable disconnect providing visible evidence that the power is\ndisconnected shall be locked open and a tag shall be posted by the individuals\nperforming the work. Locks and tags shall be removed only by the persons\nwho installed them, or if those persons are unavailable, by a person authorized\nby the operator. Repairs or maintenance shall not be performed on machinery\nuntil the power is off and the machinery is blocked against motion, e xcept\nwhere machinery motion is necessary to make adjustment;\n(t) Where electric circuits cross over or pass under belt conveyors the wiring\nshall be suitably protected; and\n(u) Switch boxes, contactors, controllers, and all other similar devices shall be\nkept free of significant accumulations of combustible dust.\n(2) The following shall apply to trolley wires and trolley feeder wires:\n(a) On all haulage roads, landings, and parti ngs where persons are required to\nregularly work or pass under bare power wires placed less than six and one -\nhalf (6-1/2) feet above the top of the rail, suitable protection shall be provided.\nThis protection shall consist of channeling the roof, placing b oards along the\nwires and extending below them, or the use of some other approved device\nthat affords protection;\n(b) All machine feed conductors shall be placed on suitable insulators which shall\nbe so placed as to prevent the conductors coming in contact  with combustible\nor conductive materials;\n(c) When the machine or feed wires are carried in the same entry as the trolley\nwire, they shall be placed on the same side as the trolley wire, between the\ntrolley wire and rib, and shall be protected from contac t therewith. Positive\nfeed wires crossing places where persons are required to travel shall be safely\nguarded or protected against persons coming in contact therewith, as required\nby paragraph (a) of this subsection;\n(d) All trolley and positive feed wires  shall be placed on opposite sides of track\nfrom refuge holes or necks of rooms when so ordered by the department, but\nwires, when protected as required by paragraph (a) of this subsection, may be\nplaced across the necks of rooms. Switches or circuit break ers shall be\nprovided to control the current at the mine and all important sections in the\nmine;\n(e) Where track is used for the return circuit, at least one (1) side shall be bonded\nto the full length of the trolley wire installation. Cross -bonds shall be installed\nnot to exceed two hundred (200) foot intervals along the track; and\n(f) All mine locomotives shall be fused or otherwise protected at the switch or at\nthe nip.\n(3) The following shall apply to surface installations:\n(a) High-voltage lines shall be at least twenty (20) feet above the ground where\nthere is a possibility of contact by traffic passing underneath;\n(b) Electrical circuits, wires, and cables shall be supported on insulators except\nwhen cables, which are of a design that can be safely us ed without insulators,\nare used;\n(c) Lightning arresters shall be installed on all ungrounded, exposed power\nconductors and telephone wires entering a mine, regardless of voltage.\nOverload protection and disconnect switches of suitable sizes and ratings\napproved by the department shall also be provided, except that they shall not\nbe required of telephone wires;\n(d) Every metallic building in which electricity is used or connected with any\ncircuit shall be effectively grounded;\n(e) All transformer tanks shall be effectively grounded;\n(f) Switch boxes, contactors, controllers, and all other similar devices shall be\nkept free of significant accumulations of combustible dust that create a fire\nhazard;\n(g) Surface transformer stations shall be housed or fenced in  when lower than\nfifteen (15) feet above the earth, and the fences shall be a minimum of six (6)\nfeet in height; and\n(h) All surface power circuits and electrical equipment shall be de -energized\nbefore work is done on the circuits and equipment except when  necessary for\ntroubleshooting or testing. When electrical work or major mechanical work is\nperformed, a suitable disconnect providing visible evidence that the power is\ndisconnected shall be locked open and a tag shall be posted by the individuals\nperforming the work. Locks and tags shall be removed only by persons who\ninstalled them or, if those persons are unavailable, by a person authorized by\nthe operator. Repairs or maintenance shall not be performed on machinery\nuntil the power is off and the machine ry is blocked against motion, except\nwhere machinery motion is necessary to make adjustments. When disconnects\nfor stationary low and medium voltage equipment that do not provide visual\nevidence that the power is disconnected are used, an adequately rated voltage\ndetector shall be used to test each phase conductor or circuit part to verify they\nare de-energized before any work is performed. When practical, confirmation\nthat the voltage detector is operating satisfactorily shall be made before each\ntest.\n(4) (a) Notwithstanding any provisions of subsection (1), (2), or (3) of this section,\nthe department may authorize the construction, maintenance, operation, or\nconducting of any activity regulated by this section, to be constructed,\nmaintained, operated, or conducted in a different manner than specified in any\nprovision of subsection (1), (2), or (3) of this section, when scientific or\nengineering information is made available to the department substantially\nindicating that the different manner would afford e qual or greater protection\nand safety than the manner required in subsection (1), (2), or (3) of this\nsection; and\n(b) The department may prescribe administrative regulations with respect to the\naboveground or underground installations in connection with a ny mine\noperation when information is made available indicating that regulation is\nreasonably necessary to prevent injury to, or loss of, life and property.\n(5) All electrical work shall be performed by a certified electrician, or an electrical\ntrainee und er the direct supervision of a certified electrician, at all underground\nmines and surface mines operating draglines or highwall miners.","path":["KRS Chapter 352"],"source_url":"https://apps.legislature.ky.gov/law/statutes/statute.aspx?id=32999","current_through":"Includes enactments through the 2026 Regular Session","vintage":"09/05/2026","retrieved_at":"2026-09-05T20:58:38Z","sha256":"813b992a9765dfa3441b780f2d7e26af2e8aa12709c6dfd61d0ef7e604528ade","source_id":"us-ky","stale":false,"prev":"us-ky/krs-352.210","next":"us-ky/krs-352.230"},"notice":"GroundRules: Original legal text. Not legal advice."}