National Electrical Code

Years › 1897 › Class E

Class E in: 18971903190519071909

Class E.

MISCELLANEOUS.

56. Insulation Resistance—

The wiring in any building must test free from grounds; i. e., the complete installation must have an insulation between conductors and between all conductors and the ground (not including attachments, sockets, receptacles, etc.) not less than the following:

Up to 5 amperes 4,000,000
Up to 10 amperes 2,000,000
Up to 25 amperes 800,000
Up to 50 amperes 400,000
Up to 100 amperes 200,000
Up to 200 amperes 100,000
Up to 400 amperes 50,000
Up to 800 amperes 25,000
Up to 1,600 amperes and over 12,500
All cut-outs and safety devices in place in the above.
Where lamp sockets, receptacles and electroliers, etc., are connected, one-half of the above will be required.
57. Protection against Foreign Currents.

a. Where telephone, telegraph or other wires, connected with outside circuits, are bunched together within any building, or where inside wires are laid in conduits or ducts with electric light or power wires, the covering of such wires must be fire-resisting, or else the wires must be inclosed in an air-tight tube or duct.

b. All aerial conductors and underground conductors, which are directly connected to aerial wires, connecting with telephone, telegraph, district messenger, burglar-alarm, watch-clock, electric-time and other similar instruments must be provided near the point of entrance to the building with some approved protective device which will operate to shunt the instruments in case of a dangerous rise of potential, and will open the circuit and arrest any abnormal current flow. Any conductor normally forming an innocuous circuit may become a source of fire hazard if crossed with another conductor charged with a relatively high pressure. Protectors must have a non-combustible, insulating base, and the cover to be provided with a lock similar to the lock now placed on telephone apparatus or some equally secure fastening, and to be installed under the following requirements:

  1. The protector to be located at the point where the wires enter the building, either immediately inside or outside of the same. If outside, the protector to be enclosed in a metallic, waterproof case.
  2. If the protector is placed inside of building, the wires of the circuit from the support outside to the binding posts of the protector to be of such insulation as is approved for service wires of electric light and power (See No. 40 a) and the holes through the outer wall to be protected by bushing the same as required for electric light and power service wires.
  3. The wire from the point of entrance to the protector to be run in accordance with rules for high-potential wires, i. e., free of contact with building and supported on non·combustible insulators.
  4. The ground wire shall be insulated, not smaller than No. 16 B. & S. gauge copper wire. This ground wire shall be kept at least three inches from all conductors, and shall never be secured by uninsulated, double-pointed tacks, and must be run in as straight a line as possible to the ground connection.
  5. The ground wire shall be attached to a water pipe, if possible, otherwise may be attached to a gas pipe. The ground wire shall be carried to, and attached to, the pipe outside of the first joint or coupling inside the foundation walls, and the connection shall be made by soldering, if possible. In the absence of other good ground, the ground shall be made by means of a metallic plate or a bunch of wires buried in a permanently moist earth.
58. Electric Gas Lighting—

Where electric gas lighting is to be used on the same fixture with the electric light:

a. No part of the gas piping or fixture shall be in electric connection with the gas lighting circuit.

b. The wires used with the fixtures must have a non-inflammable insulation, or, where concealed between the pipe and shell of the fixture, the insulation must be such as required for fixture wiring for the electric light.

c. The whole installation must test free from "grounds".

d. The two installations must test perfectly free from connection with each other.

59. Soldering Fluid—

a. The following formula for soldering fluid is suggested:

Saturated solution of zinc chloride 5 parts
Alcohol 4 parts
Glycerine 1 part

Approved Materials.

Wires—

The following is a list of wires constructed to comply with the standard given in Rule 40 a. Result of recent tests on these and on other wires can be seen at inspection offices:

Name of Wire. Manufacturer.
Americanite American Electrical Works.
Bishop Bishop Gutta Percha Co.
Clark Eastern Electric Co.
Climax Simplex Electric Co.
Simplex (caoutchouc) Simplex Electric Co.
Acme Simplex Electrical Co.
C. C. Canadian General Electric Co.
Crescent John A. Roebling's Sons Co.
Crown Washburn & Moen.
Glove Washburn & Moen.
Crefeld Crefeld Electrical Works.
Grimshaw (White core) N. Y. Insulated Wire Co.
Raven (Black core) N. Y. Insulated Wire Co.
Raven (White core) N. Y. Insulated Wire Co.
Safety (Black core) Safety Insulated Wire and Cable Co.
Habirshaw (White core) Safety Insulated Wire and Cable Co.
Habirshaw (Blue core) Ind. Rubber and Gutta Percha Ins. Co.
Habirshaw (Red core) Ind. Rubber and Gutta Percha Ins. Co.
Paranite Indiana Rubber & Insulated Wire Co.
Liberty Atlas Covering Works.
Kerite W. R. Brixey.
Okonite Okonite Co., Limited.
Paracore Nat. India Rubber Co.
N. I. R. Nat. India Rubber Co.
Double Rubber Core General Electric Co.
Double Rubber (Red core) General Electric Co.
Sterling Standard Underground Cable Co.
Tip Top Standard Underground Cable Co.
Phillips Phillips Insulated Wire Co.
Materials—

The following are given as a list of NON-COMBUSTIBLE, NON-ABSORPTIVE, INSULATING materials and are listed here for the benefit of those who might consider hard rubber, fiber, wood and the like as fulfilling the above requirements. Any other substance, which it is claimed should be accepted, must be forwarded for testing before being put on the market:

  1. Glass.
  2. Marble (filled).
  3. Slate without metal veins.
  4. Porcelain, thoroughly glazed and vitrified.
  5. Pure Sheet Mica.
  6. Lava (certain kinds of).
  7. Alberene Stone.
Iron-Armored Insulated Conduits—

The iron and steel-armored conduits manufactured by the Interior Conduit and Insulation Company, the Armorite Company, the Clifton Manufacturing Company, and the Consolidated Tube Company have been tested and, in general, have given good results in practice.

Flexible Tubing—

(See No. 24 t.)

American Circular Loom tubing is approved for use under rule 24, section t.