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Form and Status: The Code, although issued by a Government Bureau, does not have the status of mandatory law until it is adopted by Public Service Commissions or other State or Municipal authorities.

It is not in the form of a law or a designing specification but is useful as the basis upon which a law or a specification can be formed. It should not be adopted as a law or a specification without careful consideration of the conditions of the particular location to which it is to apply and modified to suit those conditions with adequate factors of safety.

The Code consists of two classes of rules: those intended to be mandatory in which “shall” or "must" is employed and those of an advisory or recommendatory nature in which "should” or “may be” is employed (p. 6): when made law to the extent it employs “shall,” in connection with construction it has more force than an ordinary specification. Every section is therefore of importance and should be carefully studied.

Division of the Code: The Code is divided into four main parts, which are preceded by sections defining the terms employed and a section on grounding.

Part 1. Contains rules for the installation and maintenance of electrical supply stations and equipment.

Part 2 Rules for the installation and maintenance of overhead and underground electrical supply and signal lines.

Part 3. Rules for the installation and maintenance of electrical utilization equipment.

Part 4. Rules to be observed in the operation of electrical equipment and lines.

Second and Third Editions Compared: In the third edition of the Code the discussion has been separated from the rules themselves and placed in a separate handbook. There is little to criticize and much to commend in Parts 1, 3 and 4. The main criticisms of this Coinmittee is to certain clauses of Part 2, which reduce the requirements for overhead wire crossings over railroads to a point considered unsafe by railroad engineers.

There are many cross-references, and until all of those are consulted and their effect estimated in modifying a given section, the full meaning of that section remains in doubt, thus rendering the Code unduly cumbersome and detracting from its value as a book of reference.

In general the requirements of the Code are more than met by the railroads in the construction of electrical supply lines paralleling railroad rights-of-way. With respect to such lines compliance with the Code should not entail additional expense for construction.

Value of the Code: The Code is valuable in establishing a not impossible standard of safety that can be adopted and maintained by the railroads. Most of the comments of the Committee on the Code will be found to be in the direction of securing greater safety. The comments of this Committee should be regarded as suggestions to perfect the Code and render it acceptable to the railroads in its entirety.

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Manner of Using the Code: Inspection of the Code will show that it requires careful study by an expert to fully determine the requirements. It is not therefore suitable to be placed in the hands of workmen for interpretation. It is valuable as a reference book for use in the preparation of rules and specifications. Used in this manner the Code will be found most helpful. Rule 550 (a) (p. 323).

Comparison with A. R. E. A. Crossing Specifications: The following detailed comments relating to Part 2 are the result of a direct comparison with the A. R. E. A. Railroad Specifications for Electric Light, Power Supply and Trolley Lines Crossing Steam and Electric Railways (Bulletin, Volume 21, No. 221, November, 1919, and in the Proceedings, Volume 21, 1920, page 208).

Detail Comments Section A-Rules Covering Methods of Protective Grounding

Rule 94 (a) (p. 27). Exception is taken to the general plan of grounding circuits, equipment and arresters to the water pipes in steel frame buildings where the water pipes are in contact with such steel work. Water mains are usually carrying more or less current and the above connection permits part of such current to enter upon the steelwork of the building affecting such structures electrolytically.

In steel buildings the water and gas pipe should have an insulated coupling placed at the place of entrance in the line. Electrical con-. nection may then be made outside such coupling on the water main side or to the steelwork of the building provided such steelwork is well grounded. Part 2 (p. 73)–Rules for the Installation and Maintenance of Over

head and Underground Electrical Supply and Signal Lines

General

A survey of one of the large railroads shows that approximately 75 per cent of the crossings are of 2,200 volts or under. The sections relating to such crossings are therefore of corresponding importance.

The code would be materially improved by separating the rules for supply lines from those for signal lines and placing the latter in a separate part. Supply lines and signal lines are handled by entirely separate interests and the commingling of the rules relating to them, while saving some space, leads to unnecessary confusion.

Rule 210 (p. 82). Grades of Construction: The general grades of construction A, B, C, D and E mentioned in various paragraphs of the code are not clearly defined. This is a serious defect in relation to a fundamental matter that should be corrected.

Rule 212 (f) (p. 84). Anchor Rod: Delete the words "except in rock or concrete” and insert the words "wherever possible.”

Rule 213 (a) (p. 84). Insulators Where Required: should have two insulators in them; one near the pole guyed and the second near the anchor pole.

Head guys

Rule 218 (b) (p. 89). Minimum Size of Conductors: At railroad crossings, No. 8 A.W.G. is permitted. Should be not less than No. 6 H.D. for potentials less than 5,000 volts and No. 4 A.W.G. for higher potentials. No soft drawn wire should be permitted.

Rule 220 (a) (p. 90). Clearances of Conductors and Wires at Crossings—Table 3: The code calls for a clearance of 28 feet above rails at supply line crossings at 60 deg. Fahr. for circuits between 300 to 1,500 volts. Most crossings are in this class.

The railroads call for 30 ft. clearance under the most unfavorable conditions for the above potentials. A temperature of 120 deg. Fahr. will make a wire sag more than will the maximum ice and wind loads at 0 deg. Fahr.

The difference between the sag of a No. 4 A.W.G. wire in a 150 ft. span at 60 deg. Fahr. and 120 deg. Fahr. is 11 in. Therefore the code permits a wire elevation 2 ft. 11 in. less than the railroads wish under the above conditions.

For higher voltage the code specifies 30 ft. at 60 deg. Fahr., which is 11 in. lower than it should be.

Exception is also taken to the 27 ft. permitted for supply lines at less than 300 volts.

The clearance below 50,000 volts should not vary with the potential, as the protection desired is against mechanical interference, not to avoid shocks.

In Table 3 it should be made clear that the 16 ft. clearance permitted in the last column applies only to trolley tracks.

Note (b) Under Table 3: Where trolley wires are only 21 feet high they should be raised and not continued at a dangerous level.

Rule 220 (p. 93), Table 4. Wire Crossing Clearances in Feet.

This table permits only 2 ft. clearance when supply wires of 0 to 7,500 volt potential cross over other wires of 0 to 750 volt potential, and 4 ft. when the potential is increased to 50,000 volts.

These clearances and others in the table are inadequate. They should be not less than 8 ft. for circuits over 5,000 volts alternating or 750 volts direct current and not less than 4 feet for other circuits.

Rule 221 (p. 95), Table 5. Minimum Line Conductor Clearances and Separations at Supports.

Many of the clearances in this table are inadequate.

(a) Horizontal Separation: The additional clearance for each kilovolt should be 0.75 in. in place of 0.4 in.

(b) Clearance From Surface of Poles, Etc.: The minimum clearance for circuits up to 10,000 volts should be 9 in. in place of 3 in. or slightly over. At 70,000 volts the clearance should be 24 in. in place of about 19 in.

(c) Clearance From Span and Guy Wires: These are inadequate in the same proportion as (b).

Rule 225 (p. 101). Climbing Space: The climbing space for higher voltages is insufficient. At 70,000 volts the climbing space is only 36 (Sec. 225) (c) to 30 in. (Sec. 225) (a) (2), depending on whether the poles are to be climbed with circuits above or not. This should be nearer 48 in.

At less than 15,000 volts a 24 in. climbing space is permissible by the code (Sec. 225 (c) Note . 102).

Rule 228 (c) (d) (p. 107). Clearances Over Buildings: Clearances should be 10 ft. for circuits 0 to 15,000 volts as well as for circuits of higher voltage.

Rule 229 (p. 108). Clearances From Bridges: The code has a varying range of clearances according to voltages. The minimum clearance should be 6 ft. where not attached.

Rule 235 (p. 115). Signal Lines Over Railways-Sub-division (b) 2: This permits Grade E construction over branch railways where no regular schedule of operation is maintained.

This rule should be eliminated because there are many branches of railroads which have no regular train schedule that carry at times as much traffic as the main line. Such roads extend around Cleveland, Indianapolis, Chicago and other cities. There are other branch railroads over which large irregular traffic is maintained but not by schedule as, under present methods of dispatching and operating trains, schedules are not necessary as they formerly were.

Section 24. Specification for Strength of Grades A, B and C Lines.

Rule 241 (p. 117). It would be better in all cases to give loading conditions for each grade of construction rather than in ratio to the requirements for another grade.

The loadings should be expressed as follows:

Heavy Loading: Wind pressure 8 lb. per sq. ft. on ice covered diameter of wires, ice coating 1/2 inch radial thickness, temperature 0 deg. Fahr.

Medium Loading: Wind pressure 8 lb. per sq. ft. on ice covered diameter of wire, ice coating 14 inch thickness, temperature 15 deg. Fahr.

Light Loading: Wind pressure 8 lb. per sq. ft. on diameter of wires, ice coating none, temperature 32 deg. Fahr.

A study of the wind and sleet storm data suggests these alternate loadings.

Heavy Loading Alternate: Wind pressure 20 lb. per sq. ft. on diameter of wires, ice coating none, temperature ( deg. Fahr.

Medium Loading Alternate: Wind pressure 15 lb. per sq. ft. on diameter of wires, ice coating none, temperature 15 deg. Fahr.

It is also believed to be desirable to change the light loading from 8 lb. wind to 10 lb. per sq. ft., using no alternate loading.

Rule 242 (b) (p. 118). Assumed Transverse Loading: This paragraph should, in our opinion, be changed to call for the same loading as that specified in Paragraph 241 for Conductors, with the addition that pressures on flat surfaces should be specified.

These recommended loadings are all given in the following table :

No Ice Surfaces Ice on Wires

on Wires Heavy Loading

Cylindrical
8 lb.

20 lb.
Flat
13 lb.

32 lb. Medium Loading Cylindrical

8 lb.

15 lb. Flat 13 lb.

24 lb. Light Loading Cylindrical

10 lb. Flat

16 lb. Rule 243 (a) (p. 119). Strength of Steel Poles: The permissible unit stresses specified in this paragraph are too high for crossings over railroads. We would recommend that for crossings over railroads the unit stresses specified in the Joint Crossings Specifications should be used, with the exception that we believe that the formula for permissible compressive stress should be changed. The stresses which we would recommend should be adopted are as follows:

Structural Steel-
Tension

.18,000 lb. per sq. in.
Shear

.14,000 lb. per sq. in.
Compression

..15,000—75 L/r
Bolts, Rivets, Pins-
Shear

14,000 lb. per sq. in.
Bearing

.28,000 lb. per sq. in. Bending

.28,000 lb. per sq. in. Guys

1/3 ultimate strength. Note (p. 120): Guys should be made of steel wire having an ultimate strength of about 75,000 lb. per sq. in.

Rule 243 (b) (p. 120). Guys: The use of guyed wide base steel towers is very objectionable in that the stresses in such structures are essentially indeterminate. If such a construction must be resorted to the guys should have sufficient strength to withstand, in the direction in which they act, the horizontal component of all the forces acting upon the tower.

Rule 243 (c) (p. 120). Total Minimum Strength (e) Tests: With the loads and unit stresses recommended above, these paragraphs are unnecessary and should be omitted.

Rule 243 (g) (p. 121). This paragraph should be modified to provide that no material less than 74-inch in thickness shall be used in structures at railroad crossings.

Rule 244 (a) (b) (c) (p. 121-122). Strength of Wood or Concrete Supports: The selection of a better quality of material does not justify a reduction in assumed loadings. If any change is to be made it should be made in the permissible fiber stress. The factor of safety in wooden poles should be greater six than two, as permitted by this code.

In Rule 244 (a). Fifty per cent should be changed to 33 per cent.

Rule 244 (c). Is objectionable but it does not apply to crossings over railroads.

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