(a) Conditions of use. Tramming the continuous mining machine in and out of the mine and from section to section must be done in accordance with movement requirements of high-voltage power centers and portable transformers (§ 75.812) and as follows:
(1) The power source must not be located in areas where permissible equipment is required;
(b) Testing prior to tramming. Prior to tramming the continuous mining machine,
(1) A qualified person must activate the ground-fault and ground-wire monitor test circuits of the power sources specified in paragraph (c) of this section to assure that the corresponding circuit-interrupting device opens the circuit. Corrective actions and recordkeeping resulting from these tests must be in accordance with §§ 75.832(f) and (g).
(2) Where applicable, a person designated by the mine operator must activate the test circuit for the grounded-phase detection circuit on the continuous mining machine to assure that the detection circuit is functioning properly. Corrective actions resulting from this test must be in accordance with § 75.832(f).
(c) Power sources. In addition to the power center specified in § 75.825, the following power sources may be used to tram the continuous mining machine.
(1) Medium-voltage power source. A medium-voltage power source is a source that supplies 995 volts through a trailing cable (See Figure 1 of this section) to the continuous mining machine. The medium-voltage power source must -
(i) Not be used to back-feed the high-voltage circuits of the continuous mining machine; and
(ii) Meet all applicable requirements for medium-voltage circuits in 30 CFR 75.
(2) Step-up transformer. A step-up transformer is a transformer that steps up the low or medium voltage to high voltage (See Figure 2 in this section) and must meet the following requirements:
(i) The trailing cable supplying low or medium voltage to the step-up transformer must meet the applicable requirements of 30 CFR part 75;
(ii) The high-voltage circuit output of the step-up transformer supplying power to the continuous mining machine must meet the applicable provisions of § 75.824;
(iii) The step-up transformer enclosure must be -
(A) Securely mounted to minimize vibration on:
(1) The continuous mining machine; or
(2) A sled/cart that must be connected to the continuous mining machine by a tow-bar and be in close proximity to the mining machine.
(B) Grounded as follows:
(1) Connected to the incoming ground conductor of the low- or medium-voltage trailing cable;
(2) Bonded by a No. 1/0 A.W.G. or larger external grounding conductor to the continuous mining machine frame; and
(3) Bonded by a No. 1/0 A.W.G. or larger external grounding conductor to the metallic shell of each cable coupler.
(C) Equipped with:
(1) At least two interlock switches for each of the enclosure covers; and
(2) An external emergency stop switch to remove input power to the step-up transformer.
[75 FR 17549, Apr. 6, 2010]