30 C.F.R. Subpart G—Trailing Cables
Title 30 - Mineral Resources
[Statutory Provisions] Trailing cables used in coal mines shall meet the requirements established by the Secretary for flame-resistant cables. Cables shall be accepted or approved by MSHA as flame resistant. [57 FR 61223, Dec. 23, 1992] [Statutory Provisions] Short circuit protection for trailing cables shall be provided by an automatic circuit breaker or other no less effective device approved by the Secretary of adequate current-interrupting capacity in each ungrounded conductor. Disconnecting devices used to disconnect power from trailing cables shall be plainly marked and identified and such devices shall be equipped or designed in such a manner that it can be determined by visual observation that the power is disconnected. Circuit breakers providing short circuit protection for trailing cables shall be set so as not to exceed the maximum allowable instantaneous settings specified in this section; however, higher settings may be permitted by an authorized representative of the Secretary when he has determined that special applications are justified: Fuses shall not be employed to provide short circuit protection for trailing cables unless specifically approved by the Secretary. Dual element fuses having adequate current-interrupting capacity shall meet the requirements for short circuit protection of trailing cables as provided in §75.601, however, the current ratings of such devices shall not exceed the maximum values specified in this section: [Statutory Provision] When two or more trailing cables junction to the same distribution center, means shall be provided to assure against connecting a trailing cable to the wrong size circuit breaker. [Statutory Provision] One temporary splice may be made in any trailing cable. Such trailing cable may only be used for the next 24-hour period. No temporary splice shall be made in a trailing cable within 25 feet of the machine, except cable reel equipment. Temporary splices in trailing cables shall be made in a workmanlike manner and shall be mechanically strong and well insulated. Trailing cables or hand cables which have exposed wires or which have splices that heat or spark under load shall not be used. As used in this section, the term “splice” means the mechanical joining of one or more conductors that have been severed. [Statutory Provisions] When permanent splices in trailing cables are made, they shall be: (a) Mechanically strong with adequate electrical conductivity and flexibility; (b) Effectively insulated and sealed so as to exclude moisture; and (c) Vulcanized or otherwise treated with suitable materials to provide flame-resistant qualities and good bonding to the outer jacket. (d) Made using splice kits accepted or approved by MSHA as flame resistant. [35 FR 17890, Nov. 20, 1970, as amended at 57 FR 61223, Dec. 23, 1992] [Statutory Provisions] Trailing cables shall be clamped to machines in a manner to protect the cables from damage and to prevent strain on the electrical connections. [Statutory Provisions] Trailing cables shall be adequately protected to prevent damage by mobile equipment. [Statutory Provisions] Trailing cable and power cable connections to junction boxes shall not be made or broken under load.
Title 30: Mineral Resources
PART 75—MANDATORY SAFETY STANDARDS—UNDERGROUND COAL MINES
Subpart G—Trailing Cables
§ 75.600 Trailing cables; flame resistance.
§ 75.600-1 Approved cables; flame resistance.
§ 75.601 Short circuit protection of trailing cables.
§ 75.601-1 Short circuit protection; ratings and settings of circuit breakers.
------------------------------------------------------------------------ Maximum allowable circuit Conductor size AWG or MGM breaker instantaneous setting (amperes)------------------------------------------------------------------------14....................................................... 5012....................................................... 7510....................................................... 1508........................................................ 2006........................................................ 3004........................................................ 5003........................................................ 6002........................................................ 8001........................................................ 1,0001/0...................................................... 1,2502/0...................................................... 1,5003/0...................................................... 2,0004/0...................................................... 2,500250...................................................... 2,500300...................................................... 2,500350...................................................... 2,500400...................................................... 2,500450...................................................... 2,500500...................................................... 2,500------------------------------------------------------------------------
§ 75.601-2 Short circuit protection; use of fuses; approval by the Secretary.
§ 75.601-3 Short circuit protection; dual element fuses; current ratings; maximum values.
------------------------------------------------------------------------ Single conductor Two conductor cable cable ------------------------------------- Conductor size (AWG or MGM) Max. Max. Ampacity fuse Ampacity fuse rating rating------------------------------------------------------------------------14................................ ........ ....... 15 1512................................ ........ ....... 20 2010................................ ........ ....... 25 258................................. 60 60 50 506................................. 85 90 65 704................................. 110 110 90 903................................. 130 150 105 1102................................. 150 150 120 1251................................. 170 175 140 1501/0............................... 200 200 170 1752/0............................... 235 250 195 2003/0............................... 275 300 225 2254/0............................... 315 350 260 300250............................... 350 350 285 300300............................... 395 400 310 350350............................... 445 450 335 350400............................... 480 500 360 400450............................... 515 600 385 400500............................... 545 600 415 450------------------------------------------------------------------------
§ 75.602 Trailing cable junctions.
§ 75.603 Temporary splice of trailing cable.
§ 75.604 Permanent splicing of trailing cables.
§ 75.605 Clamping of trailing cables to equipment.
§ 75.606 Protection of trailing cables.
§ 75.607 Breaking trailing cable and power cable connections.
