[QE003A1016B], Letter from Harold P Brown to New York Post, June 5th, 1889
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Title
[QE003A1016B], Letter from Harold P Brown to New York Post, June 5th, 1889
Editor's Notes
To the Editor of the Evening Post: Sir: The death of the poor boy Streiffer, who touched a straggling telegraph wire on East Broadway, on April 15th and was instantly killed, is closely followed by the death of Mr. Witte, in front of 200 Bowery, and of William Murray, at 616 Broadway, on May 11th, and any day may add new victims to the list. After every such accident the newspapers clamor to have the wires placed underground, while the electricians connected with the system at fault hold their peace or throw the blame on the telephone wires, until the matter has been forgotten. As an electrical engineer, I know that burying the wires woud not remedy the trouble,* though it would largely diminish the risk, while the enforcement of a few common-sense regulatons would make it almost impossible to kill a man from an arc-light current. It will not do for electricians to state that they "don't know what killed that man," for, unless they take prompt measures to make their business safe, some terrible accident will cause the adoption of laws to regulate electric lighting, which, being framed by their enemies, will cripple or destroy their business.##So, at the risk of offending some corporations having heavy investments in unsafe systems, I will venture to state a few facts, which I trust the press will be kind enough to publish widely, as no disinterested electrician will deny my statements.##It is well known that a continuous current of "low-tension," such as is used by the Edison Company for incandescent lights, is perfectly safe as far as life risk is concerned. From this fact the false popular impression has arisen that all incandescent systems are safe and all arc systems dangerous. But it is not to the "low-tension" alone that this current owes its safety, since a factor fully as important is the even, steady quality of its delivery. That is, a current of "high-tension," but unbroken and continuous, may be perfectly safe if properly operated, while a current of lower "tension," but wavy or pulsating, is always dangerous. And when these pulsations rise in speed and intensity, the danger increases, until the climax is reached in what is called "alternating current," in which impulses are given first in one direction and then in the other, several thousand times a minute. To understand the reason for this, it is necessary to remember that when a current through a wire or other conductor is on made or broken, as current in the opposite direction is "induced" in any parallel conductor; the same effects are produced in a less degree when the first current pulsates, but are intensified when it is alternated or reversed in direction. Any one who has held the metal handles of a " medical " (Galvano-Faradic) battery, had a practical experience of the power of induction and pulsation; in this apparatus the current from the battery itself is so feeble that it cannot be detected without the use, instruments, charged with the fatal current, and some other conductor having except by the metallic taste when the terminals are touched by the tongue. This insignificant current is passed through a short piece of insulated wire coiled around an iron core, and is interrupted by a rapidly vibrating armature, thereby inducing in another and longer coil , wire surrounding the first, a series of shocks, whose intensity can produce most intense suffering, or even death, in a human being who forms a portion of the circuit. It is the rapid succession of shocks that kills, while a single steady impulse of the same intensity would do little damage. Two of the leading arc-lighting systems have dynamo-electric generators provided with what are known as "open-circuit armatures," which produce a pulsating current somewhat similar in kind to the one just described, though a thousand times more powerful. It is to this current that nearly all the deaths caused by arc-lighting systems must be attributed. These "open-circuit-armature" system were pioneers in electric lighting, and at the time they were invented, it was supposed that the "closed-circuit armatures," which produce the steady and safer current, could not be made to develop sufficient electro-motive force to operate a number of are lamps upon one circuit. But the recent advances in the science have made possible "closed-circuit-armature" generators, which give the same amount of current and electro-motive force, with it much less expenditure of motive power, so that there is now valid reason for the existence of the oki type, with its pulsating and dangerous current. I do not mean to have it understood that the "steady" current is always safe, or that the "pulsating" is always unsafe, for any current with more than fifty are lamps in series is dangerous and should be prohibited; while the "pulsating" current, if its circuit is kept thoroughly insulated and carefully watched and tested every, day, may run for years without a fatal accident. But the fact remains that the "steady " current, with fifty or less lamps in circuit, has had to my knowledge, but few victims against the scores killed and maimed by the " pulsating" current. And even these were responsible for their fate, since all were employees, and should have known better. Some of them tried to disconnect apparatus through which they knew the current was flowing, and thus got into the circuit, while the others received the full current while trying to repair broken wires, which were known to be charged. But the persons killed by the other system, as a general thing, have been in no way responsible for the accidents that has caused their death; they have, as did you. Streiffer, touched or ran against apparently harmless wire when standing on a damp place, or have touched at the same moment some metal accidently charged with the fatal current, and some other conductor having a "ground" connection, as did Mr. Witte. I do not believe with extremists that the "pulsating" current should be prohibited, but I do think that conditions of safety should be rigidly enforced by the authorities. If the circuit carrying the "pulsating" current is perfectly insulated at all times, no accident is likely to occur. But if, through wearing of the insulation or a heavy rain, a connection between the circuit wire and the "ground" is formed, anyone who touches the wire and a "ground," will receive a portion of the current; if he happens to be near the other "ground," he receives but a small shock but if there are a number of lam, between him and the other connection, the shock may be fatal. Of course the reply will be made that all the arc-lighting stations in this country use insulated wire, "as required by the underwriters," but here is just where a great mistake has been made, and the sooner this is corrected the better for the cause of electric lighting. It is an open secret among electricians that the wire known as "underwrite, wire" has a very poor insulation, even when new and during dry weather, but practically no insulation at all during a rain. The paint dries out of it after a few months' exposure, other wires rubbing against it soon wear away the cotton and expose the metal, and it is altogether unfitted for outdoor use. Among electric-lighting men it is appropriately called "undertaker's wire," and the frequent fatalities it causes justify the name. Even with the most conscientious electric-light superintendent, who tests his circuit carefully for "grounds" every day before starting the dynamos, there is no surety that, during the run, some telegraph wire may not drop upon his circuits, wear away the insulation, and set a death trap for the unwary, who may be miles away from an electric lamp. (See page 47.) [See page lv, App.] The condition of the electric-light circuits in the lower part of the city is simply disgraceful, as has been previously pointed out. Most of them were first put up years ago; they have been cut and patched until full of joints, from which the tape flutters; the insulation is entirely worn off in places or hangs in shreds, and few circuits are fit to run with safely for a single hour. They cross and recross the structures of the elevated roads; they sag and sway in loose loops and are intersected at all levels by telephone and telegraph wires. On some of the circuits two or more dynamos are run in series, thus more than doubling the life risk, and it is almost certain that it was these overloaded circuits that killed Streiffer and Witte. If the Board of Electrical Control cannot force the wires underground, they can at least condemn these lines, which the Companies can afterward utilize by re-insulating for their under-ground circuits. The underwriters ought to have an eye to this also; for every bare or poorly insulated spot is a menace to property as well as life. But if "influence" prevents the wires front being replaced (and it seems to permit the extension of new wires elsewhere) there are a few simple precautions which, if enforced, will make fatal accidents almost impossible. All the deaths due to arc lighting, as far as reported, have been caused by the victim's breaking the circuit and placing himself in the break to receive the fatal" extra current" thus caused, or by his making a "ground" connection with a circuit on which there was another "ground." Both of these dangers can be avoided by very simple apparatus. If a voltameter, or a circuit of very high resistance, be connected across the poles of every arc-light dynamo, the external circuit battery be opened without producing the death-flash, as most of the "extra current" will go through the bypass. This would prevent a large proportion of the fatal accidents. If every arc-light dynamo was also provided with a wire of very high resistance leading front the circuit to the “ground," upon which was interposed apparatus to shut off the production of current the instant a second "ground" occurred, no deaths could be caused except by foolhardy carelessness. The latter apparatus could also be used to shut down the current in case the external circuit should be broken. With these precautions, and with the number of lamps limited to fifty on a single circuit, even the "pulsating" current would be fairly safe, but as the stations are now operated upon circuits with frayed and worthless insulation, they are a constant menace to all who walk the streets, use a telephone, or touch a wire. In regard to the popular impression that all incandescent electric-lighting systems are safe, I am sorry to say that, recently, several companies, who have more regard for the almighty dollar than for the safety of the public, have adopted the "alternating" current for incandescent service. If the "pulsating" current is dangerous, then the "alternating" can be described by no adjective less forcible than damnable. With the "pulsating" current, three contingencies must ordinarily arise to produce fatal results: There must be a "ground" connection on the circuit; a person must touch the circuit at some distance from the first "ground" and must, at the same instant, be in connection with the "ground" himself. But the "alternating" current produces fatal results by simply touching the two parallel wires, always close together, connections from which enter every house, or by touching a single wire al any 'mini when standing on a damp place. Its supporters may say that on account of its danger they do not permit the "primary" or death current to enter the house, but supply the lamps from the "secondary" current. True, but between these two circuits is interposed nothing more than a thin layer of cotton or silk insulation, and, as has happened again and again, it requires but a flash of lightning, or a little moisture in the converting apparatus, to bring the death-current to each lamp. The only excuse for the use of the fatal "alternating" current is that it saves the company operating it from spending a larger sum of money for the heavier copper wires which are required by the safe incandescent systems. That is, the public must submit to constant danger front sudden death, in order that a corporation may pay a link larger dividend. I do not know of a single disinterested electrician of high standing who does not condemn the alternating system. Siemens & Halske, a firm of electricians with a world-wide reputation, have spent years of experiment upon it, but have abandoned it as unsafe, and say that its use should be prohibit.' by law. Following the example of Chicago, the Board of Electrical Control should forbid the use of the fatal alternating current, and legislatures, city councils and life-insurance managers should see to it that stringent laws and regulations be passed to prevent this wholesale risk of human life. The placing the wires of the alternating system underground would only intensify the danger in houses where it might be used, while its use with underwriter's wire, in a city like this, is as dangerous as a burning candle in a powder factory. If the death of these three men can effect the adoption and enforcement of regulations similar to the following, they will not have died in vain RULES FOR STATION LIGHTING. Not more than fifty arc lights shall he operated upon any one circuit, unless said circuit is used exclusively for street lamps mounted upon wooden poles; in this case the number must not exceed sixty. All outdoor arc-lighted circuits must be provided with water-proof covering having an insulation resistance of not less than one-eightieth megohm per mile per hundred volts. Any circuit falling below this must not be used until restored. No arc-light dynamo shall be operated unless provided with a voltameter across its terminals, or other devices to provide a path for the extra current caused by opening the external circuit.* No arc light dynamos shall be operated unless provided with means for automatically stopping the production of current the instant a ground connection is made upon its circuit. No arc-light dynamo shall be operated unless provided with means for automatically breaking or short-circuiting the field circuit the instant the external circuit is broken, in order to prevent a current from being built up by the broken circuit ends falling upon some conductor. No alternating current with a higher electro-motive force than three hundred volts shall be used. Harold P. Brown, Electrical Engineer
Author
Recipient
Date
1889-06-05
Type
Folder/Volume ID
QE003-F
Microfilm ID
115:1030
Document ID
QE003A1016B
Publisher
Thomas A. Edison Papers, School of Arts and Sciences, Rutgers University