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SUBCHAPTER D-ELECTRICAL EQUIPMENT, LAMPS, METHANE DETECTORS; TESTS FOR PERMISSIBILITY; FEES

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18.54 Drawings and specifications required. 18.55 Constructional requirements.

18.56 Final inspection.

18.57 Issuance of permit.

18.58 Duration of permit. 18.59 Permit label.

18.60 Withdrawal of permit.

AUTHORITY: The provisions of this Part 18 issued under secs. 2, 3, 5, 36 Stat. 370, as amended, secs. 201, 209, 212, 66 Stat. 692, 703, 709; 30 U.S.C. 3, 5, 7, 471, 479, 482.

SOURCE: The provisions of this Part 18 appear at 20 F.R. 5712, Aug. 9, 1955, unless otherwise noted.

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As used in this part, the following terms have the meanings indicated:

Approval. Official written notification issued by the Bureau of Mines stating that the equipment complies with the regulations in this part for use in gassy and dusty mines.

Branch circuit. Parallel circuit, such as for headlight or drill, connected to the main circuit in a machine.

Certification. Official written notification issued by the Bureau of Mines stating that an electrical component complies with the requirements for explosion-proof construction and therefore is suitable for assembly as part of permissible equipment.

Connection box. Enclosure mounted on a machine to facilitate wiring of the machine without the use of permanent splices.

Distribution box. Portable enclosure in which one or more trailing cables from permissible machines may be connected to a common source of electrical energy.

Explosion-proof. Capable of withstanding internal explosions of methaneair mixtures without ignition of surrounding explosive methane-air mixtures and without damage to the enclosure or discharge of flame.

Incendive spark. An electric spark of sufficient intensity to ignite flammable methane-air mixtures.

Junction box. Stationary mounted enclosure by means of which one or more cables from permissible machines may be connected to a fixed (stationary) circuit.

Mobile equipment. Equipment which is self-propelled.

Normal operation. The performance of those functions for which the part was designed.

Permissible equipment. Completely assembled equipment to which an approval plate, label, or other device is attached as authorized by the Director of the Bureau of Mines under section 212 (a), Federal Coal Mine Safety Act (66 Stat. 692; 30 U. S. C. secs. 451-483).

Permit. A special written certificate of authorization prescribing the conditions under which a machine built or purchased for experimental purposes may be operated in a gassy mine.

Portable (trailing) cable. A flexible cable or cord by means of which portable, semi-portable, or mobile mine equipment may be connected to a source of electrical energy. The portable (trailing) cable is that portion of the power-supply system between the last overcurrent protective device on the system and the mobile equipment for which the cable furnishes electric power.

Portable equipment. Equipment that may be moved frequently and therefore constructed or mounted so as to facilitate moving it from place to place.

Pressure-piling. Abnormal explosion pressures resulting from the ignition of an explosive mixture that has been precompressed.

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NOTE: When less than 20 explosion tests are required, the fee shall be $35. (c) Each series of tests necessary to

prove the adequacy of electrical
clearances, insulation durability,
intrinsic safety, surface temper-
ature, or ventilation of each
enclosure

(d) Each field inspection of com-
pletely assembled equipment_-_
(e) Tests of portable cable:

1. Damage-resistance tests__.
2. Development tests to deter-
mine resistance to damage
by mine car running over
cable will be charged at the
rate of $10 for each five
runs over the cable. The
minimum charge is $25.
3. Flame-resistance tests_
4. Development flame-resistance

tests will be charged at the
rate of $10 per test sample.
The minimum charge is
$25.

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80

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50

50

(f) Examining and recording drawings

and specifications preparatory to issuing an approval___. (g) Examining and recording drawings and specifications for each investigation of a motor, starter, or other individual explosion-proof unit considered independently of a complete machine assembly for certification___. (h) Examining and recording drawings and specifications for an extension of approval. --

(i) Examining and recording drawings and specifications for an extension of certification----. (j) No charge will be made for inspections and tests made solely for the Bureau's information.

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NOTE: When investigation, inspection, or testing is required to be performed at locations other than the Bureau's premises, the applicant shall reimburse the Bureau for traveling, subsistence, and incidental expenses of its representative (s) in accordance with standard Government travel regulations. Such reimbursement shall be in addition to the fee charged for investigation, inspection, or testing.

Any funds deposited with the Bureau that exceed the fees required in accordance with the above charges will be refunded at the completion of the work or applied to future work, as directed by the applicant. [Sched. 2F, 30 F.R. 3754, Mar. 23, 1965] § 18.4 Application for approval of equipment.2

Before the Bureau of Mines will undertake the active investigation leading to approval of any equipment 3 the manufacturer or assembler shall make application by letter for an investigation of that equipment. This application in duplicate, accompanied by a check, bank draft, or money order payable to the U.S. Bureau of Mines to cover all necessary fees, shall be sent to the Central Experiment Station, Bureau of Mines, 4800 Forbes Avenue, Pittsburgh, Pennsylvania, 15213, together with drawings and specifications as prescribed in § 18.5. § 18.5 Drawings and specifications required.

(a) The drawings and specifications shall be sufficient in number and detail

'The submission by or on behalf of a manufacturer or assembler of any type of apparatus for test implies acceptance by him of all the terms and conditions set forth in this part.

8 Equipment for foreign shipment must meet the same requirements as that for domestic shipment.

to identify the design fully. Drawings must be numbered and dated to facilitate identification and reference in the records. The complete rating of each motor, and the setting of overload protective devices and the capacity of all fuses, shall be specified.

(b) An assembler who does not make the electrical parts for his machine shall submit a lay-out drawing (see figure 1) together with the following information, either on the drawing or attached thereto: (1) Each motor, controller, other electrical parts, and the wiring between them including conduit protection, (2) the rating of each motor, (3) the flameresistant portable cable, including gage of conductors, range of length, type (two-conductor round type G, flat twin type G, etc.), and (4) protection for the portable cable, such as circuit breaker rating, make, and current rating of trolley tap fuses (attachments for return conductor and frame ground conductor should be included). In addition, he shall submit the following information where applicable: (5) The current setting of overload relays and circuit breakers, and current rating of fuses, (6) details of insulated strain clamp for portable cable if supplied by the assembler, (7) a connection or wiring diagram if necessary to specify connections, (8) any other detail information necessary to specify properly essential features of the assembly. Specific identification of the parts must be given (by style number, drawing-list number, mechanical specification number or other data) so that they can be identified in the Bureau's records as having been investigated. A factory inspection sheet similar to the Sample Factory Inspection Sheet shown in § 18.6 must be prepared by the assembler for his use to assure that a proper inspection is made before an approval plate is attached to the machine.

(c) A manufacturer who makes accessory parts of a machine shall furnish, in addition to the material and information listed in paragraph (b) of this section, the following material and information:

(1) A drawing or drawings that shall specify the material and detailed dimensions of all parts (i) that make up explosion-proof enclosures made by him for units included under Class 1 (see § 18.11) and (ii) that form any portion of the joints through which flames might escape. Upon request, the manufacturer shall specify the material and dimen

Trolley tap..

Rail hook. Fused to? amps. 'for 230 volts.

If fused trolley tap is not used, any connection and wiring to the outer end of the cable shall be made in accordance with recognized standards of safety. The cable or circuit to the machine must have adequate fuse or other automatic circuit protection. Unless connection is in pure intake air, the trailing cable shall be connected by means provided on permissible equipment.

MOTOR

-Frame No. 53-explosion-tested, 5 hp. 230 volts d. c. 1,150 r. p. m, Identification

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No. 6 two-conductor type G flame-resistant portable cable 25' to 500' long.

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sions for such other parts as the Bureau considers necessary for proper record.

(2) Any other drawings found necessary to identify or explain any feature that has to be considered in determining whether a machine or parts thereof meet the requirements. For example, when a motor has a bearing of complex flamepath construction, the drawings should include a section through the bearing to show the relative position of each part in the assembly.

(3) A wiring diagram.

(4) If the drawings do not clearly indicate the purpose and functioning of electrical interlocks and special features in automatic or remote-control circuits, a description explaining their purpose shall be furnished.

(d) The following exception is made concerning the type of drawings required for squirrel-cage induction motors: In lieu of furnishing individual detailed shop drawings, the motor manufacturer may, if he wishes, supply one or more "skeleton" drawings for official record, giving essential information concerning the materials of which the parts are made, as well as dimensions and clearances at all flame paths, such as joints, bearings, and cable entrances, for the motor and its conduit box. If full detailed dimensions are not given for all parts, this drawing (or drawings) may show the assembled motor in section, but

4 Tre reason for limiting the exception to squirrel-cage induction motors is that this type of motor is nonsparking in normal operation.

the section or sections must show the parts in their correct proportions and location with respect to each other. A skeleton drawing shall not cover more than one motor-frame diameter. Information covering the ratings, range of voltages, speeds, and frequencies for which the motor will be available in this frame should be included on the skeleton drawing. Each frame shall have a suitable designation for purposes of reference and identification. In addition to the foregoing, detailed shop drawings will be required in connection with the initial inspection of a given motor. Such drawings will be used in making the inspection and will serve as a guide in determining whether sufficient information is given by the skeleton drawings. These detail drawings will not be officially listed or recorded.

(e) The Bureau reserves the right to make periodic factory inspections of motors submitted pursuant to this paragraph, for which listed charges will be made.

§ 18.6 Factory inspection forms.

Every manufacturer shall furnish to the Bureau a copy of the form that will be used by him in the inspection of assembled equipment at the factory. This form shall draw special attention to the wiring as well as to features that must be observed in order to make certain that explosion-proof enclosures are complete in all respects and agree with drawings filed with the Bureau. The following sample form may be used as a guide in drafting one suited to a particular ma

chine:

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