How to Avoid the New Danger That Threatens Firemen.
The very best information yet made public regarding the duty of firemen with reference to avoiding electric wires while at fires, was imparted by Mr. J. R. Beckwith, in a letter to the new Fire Board of New Orleans, last week. Referring to the death of the fireman who was shocked by electricity, he continues: Your connection with the fire department throwing upon you and your associates a very large responsibility, increased to an alarming extent by the existence of an installation of electric light lines, under permission of municipal grant or legislation authorized to convey through our streets currents of electricity of such deadly potential as to make the destruction of propeity and human life an unavoidable sequence, is my excuse for inviting your personal attention to a source of danger to the lives of firemen while engaged in the extinguishment of fires, to which little attention has apparently been given, and which, when comprehended, can in a measure be evaded, but not entirely avoided as long as the city permits electric light wires to remain as at present Installed.
In the alternating system for incandescent lighting, the current is of the most deadly character known, and will destroy life at a much lower potential than any current on any direct cuttent system.
In order to reduce the voltage and potential of its main lines in the incandescent system so as to make it available lor incandescent lighting, there is installed in the system a contrivance, letmed a converter, which is inclosed in the cast iron box that can be seen attached either to the line pole or some part of the premises to be lighted. This device consists of a coil of wire connected directly with the main line ami receiving the main lino current. Near to this coil, in the cast iron box, another coil of wire is placed, the wire being of different size and so adjusted as not to be in metallic contact with the main line current. For some unknown reason the existence of a current in the coil attached to the main line, alternating in character, sets up, by alleged induction, and apparently creates a like current in the isolated coil, not connected with the main line. The relative energy of the current established in this isolated or detached coil is determined by the relation ol the section of the wire used in the two coils. As long as this converter is in order and there is no electric connection between (he mainline coil and the isolated coil or they are sufficiently far apart ot isolated from each other, nothing of the main line current passes directly into the premises 10 be lighted ; but the very moment that the potential on the main line becomes strong enough to leap across the s|ace between the two coils, the line current, with its high potential, is carried directly into the building in its full destructive energy.
Economy in the construction of the converters and in their operation demand that the coils in the converter be placed as near in contact as possible, yet keep out the main line current. Under ordinary pressure, if it happens by accident that the two coils make metallic contact, the same result follows, l’he same is true, it the converter box is invaded by any substance or fluid that will act as a conductor of electricity from the primary to the secondary coil.
Unless the converter box is absolutely water-tight this will always occur when a jet of water with high velocity is thrown on the converter box and sufficient water driven into the box to make water contact between the coils. The firemen should be thoroughly imptessed with this fact and be instructed to avoid throwing any jets or streams of water at any converter or the iron box in which it is contained. It may cause death for the reasons given below. The firemen should also be thoroughly impressed with the fact that while it is not certain that electricity does allegiance to either ihe law of gravity, inertia or momentum, it is certain that its How is universally in the direction of least resistance, and will divide its current or flow for that purpose, without any apparent regard to the direction of either the main line or the diverted flow. If the firemen are impressed with this fact and keep it in mind, much danger will be avoided. They should remember always and on all occasions that water is a good conductor of electricity, and that a current of electricity will leave any line of wire charged with high duty as a conductor to flow along a jet of water from a fire engine thrown against the wire. If the jet only strikes one wire of the charged line, then it is probable that all of the leakage on that line will find a short circuit or ground down the stream or jet to the metallic nozzle of the line hose, and if the line of least resistance to the ground from the nozzle is through the man or men holding the nozzle, it will pass through them to the ground.
If the poles and line wire are wet, either from atmospheric or artificial conditions, it is unsafe to believe for a moment that the grounding of the leak on any of the lines will not destroy life. Therefore, no fire engine can play its stream on a line with a primary alternating current without the almost certain danger that the man at the nozzle will be stricken down and killed by the leak, and that such contact is sufficient to destroy life. If a jet is played on the converter until it is filled with the water sufficient to connect the two converter coils with a water medium, a series of calamities may happen if the line is alive at the time. There is danger that a current will flow down the jet playing on the ‘converter and injure or destroy the man at the nozzle. But this is a small portion of the danger from this source, or that may result from wetting the interior of the converter boxes. The moment the coils in the box are in electrical contact the primary high voltage current of the main line flows into the service wire leading into the building, and any other engine playing on or in the building whose jet strikes the service wires in the building will get the current back to its nozzle through the jet to practically the full potential of the main line high enough to destroy life’ even though, through resistance in the service wires, the potential at the point of contact with the service wire may be less than the main line. If the contact is imperfect or partial there is still danger of a shock that will disable a man. The chances of the destruction of life by such contact may be stated to be at least nine in ten in favor of death. You see, therefore, that throwing a stream or jet of water on any line of wires carrying death-dealing potential means an extreme peril to life.
If it is pretended that the lines on which this terrible current is distributed, are insulated so that the current will not leave the line for water contact, this is not true, as an examination of the best constructed alternating lines will show. If the lines were, in fact, insulated with the best known insulation available for street lines, I know of no insulation that would not quickly yield to the abrasive action of a jet of water thrown with the velocity of the modern approved fire engine, unless, perhaps, it is some of the cables insulated within lead or metallic pipes, and these would he unsafe unless there was extreme care in splicing and attaching to support.
The practical question for you to deal with officially is how this danger to life can be avoided in the administration of your department. The firemen should be instructed first to avoid, if possible, allowing a jet of water to be played on a converter box wherever it may be located, whether on the line pole or on the building; second, to avoid throwing a jet of water on the service lines of wire leading from the main line into the building; third, to avoid throwing a jet of water so as to make contact with either one or both of the main line wires on the street poles; fourth, they should be compelled to make themselves thoroughly familiar with the lines and w ires in thvir own district or in the districts to which they may be called, so that some one at every fire will know and be able to point out the deadly currents. If no one present at a fire has this knowledge, then they should be instructed to consider all lines in the vicinity as dangerous, and as lines that will kill by contact. Externally, a line wire gives no indication whether it is inert or charged. This can be determined as to all direct currents by the use of a small pocket compass. If that instrument is placed near a line of wire when it is charged with electricity, the needle will cease to point north and tend to point at right angles to the current on the line. Some one connected with each engine, hose or all other equipments should have a pocket compass to test for currents. Much danger will be avoided by its use.
There is another matter that should receive serious attention from the commissioners. Recent experiments seem to demonstrate that there may be resuscitation in cases of apparent death from electric shot.
Animals have been rendered senseless and apparently dead by shocks believed to he sufficient to destroy human life, and resuscitated again by artificial respiration, applied much as in the case of drowning. The remedy must be resorted to at once to be effective, as there is no time to send for medical aid. The process or art of producing artificial respiration is simple, and may be performed by any one who has seen the operation. It is important that some medical man should be employed to instruct the men connected with the fire apparatus how to produce artificial respiration, and the men should be under strict orders to treat all persons stricken down without any delay. It can do no harm, and will probably save life if promptly and intelligently applied.