Steel Conduit Research Articles

Grounding and safety.

Several basic facts about the effects of steel conduits in A.C. power systems are reviewed to show that the geometry of a grounding path may have a greater effect on its effectiveness as a ground return path than its D.C. resistance. Data are presented on the effect of ?? E.M.T. conduit and No. 10 conductors in tests simulating regular room wiring under ground fault conditions.

Cement Mortar Lining of 20-Ft Diameter Steel Pipe

The art of cement mortar lining new steel pipelines, already installed, has advanced rapidly in the past 10 yrs. This advancement has led to the application of in-place mortar lining in a 20 ft-diam steel tunnel. This application has been described by showing there was a need for a faster and better way to apply a protective coating to large diameter steel conduits. The description includes where and how this application was performed.

A Neutron Counting System with a Fission Detector and a Flexible, Balanced Line

A neutron counting system containing a fission detector and a pulse transformer driving a balanced transmission cable was investigated to determine its usefulness as an instrument for reactor control. Because of the noise rejection capability of the balanced system input, all active elements can be located away from the hostile environment of the reactor, resulting in longer periods of trouble-free operation. The design criteria of Fowler were used as a guide. The primary objective was to measure the response of the system to electrical interference characteristic of the Oak Ridge Research Reactor (ORR). The results showed no noise pulses in excess of the alpha threshold after six days of operation at the ORR. A detector without 235U was used to make this measurement. The input cable, with a characteristic impedance of 250 ohms, was a 40-ft long double-shielded twisted pair. Its outer jacket and inner dielectric were made of irradiated polyolefin compounds. The cable was enclosed in a flexible, stainless steel conduit for underwater operation. The quality of the shield of this cable and four other types of balanced cables was determined by a measurement of their transfer impedance. To determine the effect of the flexible conduit, a separate measurement was made with the cable-conduit combination. The techniques required to make these measurements are critical and are described. The signal from the detector-cable combination requires a preamplifier with a lownoise input stage. A series-shunt feedback stage using two 2N2857 transistors gave an input noise of approximately 2.

Investigation and Testing of Footing-Type Grounding Electrodes for Electrical Installations

Footing-type grounding electrodes installed in the concrete foundations of residential and small commercial buildings designed to meet a maximum ground resistance value of 5 ohms are described. Bare solid copper electrode wires of various lengths, steel reinforcing rods, and 10-foot lengths of hot galvanized rigid steel conduit were used to determine the resistance values.

Aluminum conduit use in the hydrocarbon and chemical process industries

IN THE PAST few decades, most of us have designed and installed numerous electrical systems employing steel conduit for the raceways. For the construction and maintenance of a complete rod, bar and cable mill, the authors used approximately 20 carloads of steel conduit within the last ten years.

Determination of ground-fault current on common A-C grounded-neutral systems in standard steel or Aluminum conduit

A NEED has been indicated in the electrical industry for information which will enable the design engineer to predict the magnitude of fault current that will flow in a circuit enclosed by metal conduit when subjected to ground fault conditions. The purpose of this paper is to present usable data, obtained by laboratory tests, for the improved design of grounded-neutral circuits in rigid steel or aluminum conduit.

Determining the decrease of thickness of steel sheets and steel conduits caused by corosion: fr|M. G. Pirou. Corrosion et Anticorrosion, v. 5, no. 11, Nov. 1957, p. 339–347

Determining the decrease of thickness of steel sheets and steel conduits caused by corosion: fr|M. G. Pirou. Corrosion et Anticorrosion, v. 5, no. 11, Nov. 1957, p. 339–347

Quantity Discounts and the Morton Salt Case

HE requirements of the RobinsonPatman Act should be seriously I considered in the formulation of many pricing policies. These requirements are in such a state of flux that any exposition of recent developments in the administration of the act seems desirable. The Morton Salt case presents an excellent opportunity for such an inquiry. It is an obvious and yet significant fact that any antitrust case is at the same time a legal and a business matter and that it is not wise or possible to divorce the two points of view. This makes it necessary to straddle the areas of interest of the legal technician and the businessman. The difficulty of this task is somewhat imposing, since what is superficial treatment to the antitrust lawyer may be considered overbearing legal technicalities by the business practitioner. It is hoped that sufficient attention to both points of view has been achieved in this paper.2 Within the past few years there has been unusual activity in the antitrust field. The surprising number and variety of cases seem to have resulted in a considerable degree of on the part of lawyers, businessmen, and legislators. Some have gone so far as to suggest that a state of chaos exists. In fact, nearly everyone except the Federal Trade Commission says he is confused. Corwin Edwards, chief economist of the FTC, has characterized this widely proclaimed state of confusion on the legality of pricing practices as mere ghosties and ghoulies and six legged beasties and things that go hump in the night.' It is probably safe to say that much of the is less imaginary than Mr. Edwards would suggest. Some substantial among members of the Commission itself is found in a Senate committee report which documents statements made by various Commission members on particular pricing practices that are considered illegal. That some of these statements are inconsistent is made quite obvious.4 If it can be assumed that the antitrust situation is characterized by something less than complete clarity, the cause probably rests on some recent antitrust cases. Two of them are the Cement Institute case and the Rigid Steel Conduit case, both dealing with the broad prob1 Associate director, Market Facts, Inc.

Measuring conductor resistance and reactance

IN CONNECTION with a study of a-c resistance and reactance of large conductors in steel pipe and conduit, made for the Insulated Power Cable Engineers Association, measurements were made of isolated conductors in air, 3-cabled conductors in air, and finally the 3-cabled conductors in various sizes of conduit. Each of these stages raised measurements problems, especially when it became desirable to determine the component losses due to each of the several factors operating. It likewise became necessary to establish the accuracy with which measurements could be made.

A-C Resistance of Large Size Conductors in Steel Pipe or Conduit

The determination of the proper conductor size to carry a given power load on cables installed in steel conduits or pipes has been subject to assumptions which were not too satisfactory. The Insulated Power Cable Engineers Association engaged the Electrical Testing Laboratories to conduct a research project to large conductors installed in steel pipes. This paper reports the results of the research and gives suggested values of ratio of a-c to d-c resistance for conductor sizes up to 2,500,000 circular mils. It is felt that more accurate and uniform calculations of current carrying capacity of cables in conduit in air, or in pipe in the ground can be attained by use of the a-c/d-c conductor resistance ratios set forth herein, than by assumptions used previously, and therefore the data reported herein will be of benefit to both the manufacturer and the power user.

Reactance of Large Cables in Steel Pipe or Conduit

The determination of reactance of large conductors in steel pipes or conduits has not been susceptible of practical computation but is required for estimating the voltage regulation of pipe cable systems. The present paper gives the results of tests made by Electrical Testing Laboratories (ETL) under the auspices of the Insulated Power Cable Engineers Association, on cables from 750,000 to 2,500,000 circular mils. These data have been supplemented by data from other sources, extending the lower limit of size to 4/10 American wire gauge. Empirical formulas have been developed to include all intermediate sizes and spacings. These formulas are based on the principle of deriving a self-GMD (geometric mean distance) from the a-c/d-c resistance ratio, and using an augmented axial spacing to allow for the magnetic effect of the pipe.

Design and Construction of a Covered Concrete Reservoir

Eugene, Oregon, with a population of about 22,000 gets its water from the McKenzie River, a stream with a minimum flow of 1500 second feet and a drainage area of about 1000 square miles above the water supply intake. It has its source high in the Cascade mountains near the base of the snow clad Three Sisters. The water is conveyed to the city through a 30-inch steel conduit seven miles long and is delivered to the filtration plant by gravity. The water is soft and of good quality and although it is Coli negative a fairly large percentage of the time, it can not be used with safety without chlorination. During storm periods, amounting to a total of 10 to 15 days each winter, the water is of such high turbidity as to require treatment by coagulation and rapid sand filtration. Throughout the remainder of the year no coagulant is used and the water passes through the filters which act only as strainers for the removal of floating and suspended matter. The resulting effluent is of excellent quality and is under the control of a bacteriologist at the University of Oregon. The reservoir which is the subject of this paper was constructed in 1926 on the site of an older and much smaller one which was built in 1887 and had been in continuous use from that time until its destruction in clearing the ground for the erection of the new one. Its location is on an elevation known as Skinner's Butte, named for Eugene Skinner, the first white settler on the ground now occupied by the City of Eugene and after whom the city also is named. This Butte was owned by the local water company from whom the city purchased the water system in 1908 and the title to this property, about 60 acres, at the end of the main street and about one-half mile from the center of the business district was acquired by the city at that time. A few years later by a vote of the people it was taken

Appellate Division Affirms Typhoid Fever Damage Awards Against Albany, N. Y.

Journal AWWAVolume 20, Issue 5 p. 671-673 Article Appellate Division Affirms Typhoid Fever Damage Awards Against Albany, N. Y. Charles R. Cox, Charles R. CoxAssistant Sanitarian, Division of Sanitation, State Department of Health, Albany, N. Y.Search for more papers by this author Charles R. Cox, Charles R. CoxAssistant Sanitarian, Division of Sanitation, State Department of Health, Albany, N. Y.Search for more papers by this author First published: 01 November 1928 https://doi.org/10.1002/j.1551-8833.1928.tb13678.x AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume20, Issue5November 1928Pages 671-673 RelatedInformation

Method of Metering the Water Supplied to the Five Distribution Systems of the City of Newark, N. J.

There has recently been completed at Newark, N. J., a unique structure, figure 1, serving the dual purpose of a memorial to one of the city's most efficient former officials and a shelter for the apparatus which keeps a continuous automatic record of the quantity of water supplied to each of the five service districts. The supply for the city comes from impounding reservoirs on the Pequannock watershed about 25 miles to the northwest. The original works furnished this supply through a 48-inch and a 42-inch riveted steel conduit, connected with two distributing reservoirs in the city, called the Belleville and South Orange Avenue reservoirs. About fifteen years ago the city built a storage reservoir holding 700,000,000 gallons at Cedar Grove, 7 miles from the city, in order to have a supply near at hand in case an accident happened to the riveted steel conduits. This reservoir is supplied through a 60-inch riveted steel conduit which is connected with the 42-inch and 48inch conduits at Great Notch, a little less than a mile from Cedar Grove. From this storage reservoir a 60-inch riveted steel conduit was laid to the city. There is a Venturi meter on both the 42-inch and 48-inch conduits in the Pequannock watershed and one on the 60-inch conduit at Cedar Grove. Until the gauging devices described in this article were put in service, these three Venturi meters gave all the information that was available concerning the total quantity of water supplied to the city and the surrounding districts obtaining supplies from Newark. The connections at Great Notch and Cedar Grove are so arranged that all of the supply for the city may be sent through the storage reservoir, which is the usual operating condition, or part may go to the reservoir and part to the city, or the water sent to the reservoir