Program Policy Manual - VOLUME V - Mine Safety and Health ...

More documents

Recommendations

Info

MSHA PROGRAM POLICY MANUAL VOLUME V Where track is used as a power conductor, efficient connections require that: 1. Both rails of main-line tracks shall be welded or bonded at every joint, and cross bonds shall be installed at intervals of not more than 200 feet. If the rails are paralleled with a feeder circuit of like polarity, such parallel feeder shall be bonded to the track rails at intervals of not more than 1,000 feet. 2. At least one rail on secondary track-haulage rails shall be welded or bonded at every joint, and cross bonds shall be installed at intervals of not more than 200 feet. 3. Track switches in entries shall be well bonded. 4. In rooms where electric equipment is dependent upon the room track rails as a power conductor, rail joints shall be secured by means of fish plates, angle bars, or the equivalent, and at least one rail shall be bonded at each joint. Visible arcing or heating at rail joints indicates poor connections or poor bonding. Main-line track is interpreted to be track used to transport coal outby the junction of two or more coal-producing sections. All other track is considered to be secondary track and includes track that is used to transport miners and material or coal from a single coal-producing section. Both rails of secondary track may need to be bonded or welded at each joint if the additional current-carrying capacity is needed for compliance with Section 75.1001. Bonding as used herein means a connection used to insure the required electrical conductivity between the rails. The connection may be obtained mechanically, as with a wedge or by welding the bonds on the rails. 75.515 Cable Fittings; Suitability This Section requires fittings of such design as to prevent chafing of cable or wire insulation that would expose or accidentally ground the conductors at points where they enter the compartment walls of switch boxes, starters, motors, cable couplers, etc. Insulated wires passing through walls of metal enclosures shall be protected against damage to the insulation by February 2003 (Release V-33) 63
MSHA PROGRAM POLICY MANUAL VOLUME V insulated bushings or suitable insulating material, such as fireresistant hose conduit used in conjunction with a suitable fitting or clamp that will prevent movement of the conductor in the opening. Fittings for cables need not be insulated. When insulated wires pass through holes in metal dividers within the same enclosure, insulating bushings or other suitable insulating material shall be used to bush the holes. For the purpose of this Section, "cable" means two or more insulated conductors covered by an additional abrasion-resistant covering. 75.516 Power Wires; Support "Power wire" means a current-carrying conductor which may be bare, insulated, or part of a cable assembly. Shielded cables that meet all of the requirements of Section 75.804 are not required to be installed on insulators, even if they are used to supply low-, medium-, or high-voltage equipment. All other power wires and cables supplying belt conveyor drives, pumps, air compressors, and other units of portable or stationary equipment (except distribution boxes, portable pumps, battery chargers, and rock-dusting machines which are used on coalproducing sections and which require frequent movement) shall be installed on insulators and are not allowed to contact combustible material, roof, or ribs. Acceptable insulators are constructed of noncombustible, nonabsorptive insulating material adequate for the voltage being used. Furthermore, insulators must have sufficient mechanical strength and must be installed in such a manner as to provide adequate support for the power wires or cables installed on them. Cables that meet the requirements of Section 75.600 may be supported from noncombustible material such as sandrock or slate roof, concrete or metal roof supports, or masonry walls by lengths of flame-resistant cable or conveyor belting. Trolley wires and trolley feeder wires shall be supported only on bell-and-clip-type insulated hangers or other supports especially designed for that purpose. All wires and cables that are required to be supported on insulators shall be supported in such manner that they do not contact combustible materials, roof, or ribs. 75.516-1 Installed Insulators J-hooks shall be acceptable as insulators for the permanent installation of insulated cables if the manufacturer certifies February 2003 (Release V-33) 64
Page 1 and 2:
MSHA PROGRAM POLICY MANUAL VOLUME V
Page 3 and 4:
Page 5 and 6:
Page 7 and 8:
Page 9 and 10:
Page 11 and 12:
Page 13 and 14:
Page 15 and 16:
Page 17 and 18:
Page 19 and 20:
Page 21 and 22:
Page 23 and 24:
Page 25 and 26:
Page 27 and 28: MSHA PROGRAM POLICY MANUAL VOLUME V
Page 77: MSHA PROGRAM POLICY MANUAL VOLUME V
Page 127 and 128: MSHA PROGRAM POLICY MANAUL VOLUME V
Page 129 and 130:
MSHA PROGRAM POLICY MANAUL VOLUME V
Page 131 and 132:
Page 133 and 134:
Page 135 and 136:
Page 137 and 138:
Page 139 and 140:
Page 141 and 142:
Page 143 and 144:
Page 145 and 146:
Page 147 and 148:
Page 149 and 150:
Page 151 and 152:
Page 153 and 154:
Page 155 and 156:
Page 157 and 158:
Page 159 and 160:
Page 161 and 162:
Page 163 and 164:
Page 165 and 166:
Page 167 and 168:
Page 169 and 170:
Page 171 and 172:
Page 173 and 174:
Page 175 and 176:
Page 177 and 178:
Page 179 and 180:
Page 181 and 182:
Page 183 and 184:
Page 185 and 186:
Page 187 and 188:
Page 189 and 190:
Page 191 and 192:
Page 193 and 194:
Page 195 and 196:
Page 197 and 198:
Page 199 and 200:
Page 201 and 202:
Page 203 and 204:
Page 205 and 206:
Page 207 and 208:
Page 209 and 210:
Page 211 and 212:
Page 213 and 214:
Page 215 and 216:
Page 217 and 218:
Page 219 and 220:
Page 221 and 222:
Page 223 and 224:
Page 225 and 226:
Page 227 and 228:
Page 229 and 230:
Page 231 and 232:
Page 233 and 234:
Page 235 and 236:
show all

Program Policy Manual - VOLUME V - Mine Safety and Health ...

Create successful ePaper yourself

Delete template?

Save as template?