> > > >

1948-49 Theatre Catalog, 7th Edition, Page 260 (249)

1948-49 Theatre Catalog, 7th Edition
1948-49 Theatre Catalog
1948-49 Theatre Catalog, 7th Edition, Page 260
Page 260

1948-49 Theatre Catalog, 7th Edition, Page 260

Underground Cables for Drive-Ins

A Hidden, but All-Important Part of the Drive-In Structure is Brought Above Ground for Analysis

Among the many products designed and developed especially for drive-in theatres are underground cableseout of sight during their active life but always the indispensable and rugged nerve system and arteries of outdoor sound pictures. In the following survey, some outstanding cables which are currently in use are described, and features of interest to the drive-in operator, listed. As a general rule, because of resistance. No. 16 wire would be too light for use as a conductor in drive-in theatres; No. 14 wire would be used only up to a capacity of about 400-500 cars; and No. 12 wire would be used in all over 500 cars. The equipment manufacturer or a competent electrical engineer should decide. One of the most important properties of the underground wiring system, in its buried life. is its non-hygroscopicity or resistance to moisture. Therefore, this phase of each manufacturerls cable receives special attention. In addition. ease of handling and installation is pointed out; and splicing techniques are included in the discussion wherever this information is



According to information supplied by the Apparatus Department of the General Electric Company, their wire and cable engineers recommend G. E. twisted pair, SI-58264 heavy duty FLAMENOL, for use underground between projection booth and individual speaker posts at drive-in theatres. Its underground durability makes it a natural for outdoor applications.

Twisted pair SI-58264 is composed of two No. 12-AWG or No. 14-AWG copper wires protected by FLAMENOL insulas tion, For identification, one insulated conductor is ribbed. It is said that the FLAMENOL jackets used on these cables make them more efficient and easy to splice and handle.

FLAMENOL, which refers only to the flexible jacket or insulation and not to Specific types of cable, is the original plasticized - polyvinylchloridc insulation and was placed on the market prior to 1936. Its impervious nature provides ideal protection for drive-in theatre underground cables. FLAMENOL is chemlcally inert and therefore practically aKeless. With FLAMENOL, drive-in low-voltage circuits are protected from all these old enemies of electrical insula 1948-49 THEATRE CATALOG

tion: air, acids, alcohol, alkalis, grease, ozone, dirt, oils, sunlight, and water.

Cable insulated with FLAMENOL is easy to work. It strips easily and cleanly either with a stripping tool, or with a hand-manipulated knife; there is no braid to fray; therefore, it saves installation time and simplifies cleaning. Since it is supplied in seven colors and inlaid stripes, color coded according to NEMA standards, circuit tracing is facilitated, and installation and maintenance time are shortened. It requires no additional protective covering-its small diameter saves space. Because of its smooth hard finish, it can be pulled easily through conduits or ducts. And FLAMENOL is said to be flameproof; in fact, it owes its name to its unusual flame resistancee the insulation will char in an open flame, but will not support combustion. It has plenty of strength. According to latest available reports, FLAMENOL Style FL cable has a minimum tensile strength of 1500 pounds per square inch and a minimum elongation of 100 per cent.

In general, the manufacturer states that "FLAMENOL wire and cable are recommended for use in all circuits handling up to 600 volts, wherever durability because of resistance to moisture, age, weather, acids, alkalis, and oils is desirable, or where small diameter is important, or where the possibility of fire being spread by wire insulation must be eliminated?

Twisted pair No. 14 AWG SI-58173 is supplied in carton packed stock coils in 500 foot lengths and its approximate net price per 1000 feet in quantities from 500 to 2499 feet is $46.00. From 2500 to 4999 feet the net price per 1000 feet is $42.00; and from 5000 feet up, ap proximately $38.20. Naturally No. 12 AWG is higher.


A number of drive-in equipment manufacturers recommend a cable manufactured by Simplex Wire and Cable Company. This underground cable is manufactured in both No. 12 and No. 14 and it is reported that it has proved satisfactory in drive-in applications.

The Simplex-ANHYDREX underground cable is a twin conductor, up-to600 volt cable listed by underwriters as Type USE, each conductor having seven strands with 3/64" rubber insulation, and in turn covered with a 5/64" neoprene jacket. The basic design in detail, includes: solid or stranded, tinned copper; insulationestandard walls of ANHYDREX and a rubber-filled tape #6 and larger, a varnished cotton braid #8 and smaller, cable coil filled with waterproofed jute; and an outer sheath of hard - service, abrasion - resistant neoprene.

Neoprene sheaths resist the action of oils and acids. They do not crack when exposed to sunlight and they are flameresistant. For circuits partially below and partially above ground, one length of Simplex-ANHYDREX is said to meet all requirements fullyewithout splicing.

The manufacturer states Several reasons why this underground cable has met with approval. For one thing, Simplex-ANHYDREX cables have no outer fabric coverings, tar, or pitches to deteriorate in acid or alkaline waters, or to clog ducts and become frozen in. And moisture resistances-an important factor -is high. The rubber insulation is the ANHYDREX low water absorption compound developed for Simplex non-leaded submarine cables. This type of insulation, a product of Simplex research, is designed to withstand constant immersion in water with negligible effect on its electrical and physical properties.

An additional advantage claimed by the manufacturer is the cable's extremely simple design which reduces the need for jointing and conductor-splicing tools and materials. A sharp knife, rubber cement, rubber splicing compound, friction tape and waterproof paint are all that are necessary to joint or tap the cable.

As the company explains, "SimplexANHYDREX Cables are easy to handle, easy to install, and easy to maintain. They are easy to handle because of their Hexibility and simple construction. They are easy to install because they can be laid in a ground trench, carried around

TWO UNDERGRQUND CABLES. the Simplex-ANHYDREX. above. and the G. E. FLAMENOL below are analyzed for their potential use in the exacting duty of carrying sound to the individual mmp speakers.
1948-49 Theatre Catalog, 7th Edition, Page 260