高架电线。

高架电线。

State Fire Marshal Creamer, of Ohio, has this to say on the subject of burying overhead wires: “The multiplication of wires on poles has in many towns filled streets and alleys with dangers to life so serious that it is impossible to exaggerate them. Arc-light wires which usually carry 6,000 volts and feed-wires to trolley substations, which usually carry 30,000 volts and interburban lines of 26,500, should be on poles occupied by them exclusively, and they should have below them a screen of cheap, woven wire fencing to furnish a cradle for broken ends. This wire netting, not being continuous past the cross-arm, would not carry current. There should also he a loop of wire at the end of the cross-arm to prevent the loaded wires from falling off, if an insulator should break. Parallel lines of poles should be so far apart that a falling pole would not carry wires across the space. Recently a lineman of experience, working on a pole in front of the writer’s window, touched an arc-light wire while his leg was in contact with a telephone wire and fell dead across the wires below. I11 large cities the telephone wires are placed underground, because their number taxes the possible pole capacity, rather than for the reason that the hundreds of wires in alleys often delay work by fire departments and endanger life from cut wires coming in contact with wires carrying high voltage. Firemen dare not cut high-voltage wires such as those for arc-lights until the current is shut off. This causes delay in getting at the lire. The largest pole line carries 250 wires. Single cables are made to carry 1,200 wires, and a single underground conduit contains ducts for ninety cables—over forty times the capacity of the largest pole line. Within a few years legislatures wilPprovide statutes which recpiire that systems of high voltage shall he placed on separate lines of poles and that they have a screen under them: or. that in cities all electric wires shall be placed i’l conduits below the street pavement. An electrical engineer of long and varied experience as superintendent of power plants advocates for cities a tunnel 5x7 ft., into which wires for all purposes shall be put. This would give room for workmen to pass along the lines. It is possible that the law will require the lowering of the pressure on high pressure lines by the use of much larger copper wires; hut it would add largely to the cost of construction.”

State Fire Marshal Creamer, of Ohio, has this to say on the subject of burying overhead wires: “The multiplication of wires on poles has in many towns filled streets and alleys with dangers to life so serious that it is impossible to exaggerate them. Arc-light wires which usually carry 6,000 volts and feed-wires to trolley substations, which usually carry 30,000 volts and interburban lines of 26,500, should be on poles occupied by them exclusively, and they should have below them a screen of cheap, woven wire fencing to furnish a cradle for broken ends. This wire netting, not being continuous past the cross-arm, would not carry current. There should also he a loop of wire at the end of the cross-arm to prevent the loaded wires from falling off, if an insulator should break. Parallel lines of poles should be so far apart that a falling pole would not carry wires across the space. Recently a lineman of experience, working on a pole in front of the writer’s window, touched an arc-light wire while his leg was in contact with a telephone wire and fell dead across the wires below. I11 large cities the telephone wires are placed underground, because their number taxes the possible pole capacity, rather than for the reason that the hundreds of wires in alleys often delay work by fire departments and endanger life from cut wires coming in contact with wires carrying high voltage. Firemen dare not cut high-voltage wires such as those for arc-lights until the current is shut off. This causes delay in getting at the lire. The largest pole line carries 250 wires. Single cables are made to carry 1,200 wires, and a single underground conduit contains ducts for ninety cables—over forty times the capacity of the largest pole line. Within a few years legislatures wilPprovide statutes which recpiire that systems of high voltage shall he placed on separate lines of poles and that they have a screen under them: or. that in cities all electric wires shall be placed i’l conduits below the street pavement. An electrical engineer of long and varied experience as superintendent of power plants advocates for cities a tunnel 5x7 ft., into which wires for all purposes shall be put. This would give room for workmen to pass along the lines. It is possible that the law will require the lowering of the pressure on high pressure lines by the use of much larger copper wires; hut it would add largely to the cost of construction.”