Collapse to view only § 75.607 - Breaking trailing cable and power cable connections.
- § 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.
- § 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.
- § 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.
§ 75.600 - Trailing cables; flame resistance.
Trailing cables used in coal mines shall meet the requirements established by the Secretary for flame-resistant cables.
§ 75.600-1 - Approved cables; flame resistance.
Cables shall be accepted or approved by MSHA as flame resistant.
§ 75.601 - Short circuit protection of trailing cables.
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.
§ 75.601-1 - Short circuit protection; ratings and settings of circuit breakers.
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:
| Conductor size AWG or MGM | Maximum allowable circuit breaker instantaneous setting (amperes) | 14 | 50 | 12 | 75 | 10 | 150 | 8 | 200 | 6 | 300 | 4 | 500 | 3 | 600 | 2 | 800 | 1 | 1,000 | 1/0 | 1,250 | 2/0 | 1,500 | 3/0 | 2,000 | 4/0 | 2,500 | 250 | 2,500 | 300 | 2,500 | 350 | 2,500 | 400 | 2,500 | 450 | 2,500 | 500 | 2,500 |
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§ 75.601-2 - Short circuit protection; use of fuses; approval by the Secretary.
Fuses shall not be employed to provide short circuit protection for trailing cables unless specifically approved by the Secretary.
§ 75.601-3 - Short circuit protection; dual element fuses; current ratings; maximum values.
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:
| Conductor size (AWG or MGM) | Single conductor cable | Two conductor cable | Ampacity | Max. fuse rating | Ampacity | Max. fuse rating | 14 | 15 | 15 | 12 | 20 | 20 | 10 | 25 | 25 | 8 | 60 | 60 | 50 | 50 | 6 | 85 | 90 | 65 | 70 | 4 | 110 | 110 | 90 | 90 | 3 | 130 | 150 | 105 | 110 | 2 | 150 | 150 | 120 | 125 | 1 | 170 | 175 | 140 | 150 | 1/0 | 200 | 200 | 170 | 175 | 2/0 | 235 | 250 | 195 | 200 | 3/0 | 275 | 300 | 225 | 225 | 4/0 | 315 | 350 | 260 | 300 | 250 | 350 | 350 | 285 | 300 | 300 | 395 | 400 | 310 | 350 | 350 | 445 | 450 | 335 | 350 | 400 | 480 | 500 | 360 | 400 | 450 | 515 | 600 | 385 | 400 | 500 | 545 | 600 | 415 | 450 |
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§ 75.602 - Trailing cable junctions.
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.
§ 75.603 - Temporary splice of trailing cable.
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.
§ 75.604 - Permanent splicing of trailing cables.
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.
§ 75.605 - Clamping of trailing cables to equipment.
Trailing cables shall be clamped to machines in a manner to protect the cables from damage and to prevent strain on the electrical connections.
§ 75.606 - Protection of trailing cables.
Trailing cables shall be adequately protected to prevent damage by mobile equipment.
§ 75.607 - Breaking trailing cable and power cable connections.
Trailing cable and power cable connections to junction boxes shall not be made or broken under load.