SUPPLEMENT

Information Applicable to Naval Practices

I. HOW TO LAY OUT A MAIN WIREWAY

A. Supplies, tools, and equipment

B. Procedure

1. OBTAIN MAIN WIREWAY PRINT AND DETERMINE THE RUNS.

h. Learn cable designations and their meaning.

1) Cable designations

i. Learn to distinguish the circuits by the circuit markings on the blueprint.

j. Keep all large cables within the machinery spaces inboard of the cable rack. The remainder are to be installed in the way they will best fit the particular location.

k. Whenever possible, group power and light, I.C. and fire control, and radio.

2. CHECK ALL DETAILS ON MAIN WIREWAY PRINT SUCH AS CABLE MARKINGS AND THEIR INTERPRETATIONS, POWER, LIGHTING, FIRE CONTROL, I.C., AND RADIO.

a. Identify the different circuits, noting service they perform and where they will be found aboard a ship.

b. List in small notebook all I.C. and fire control circuits, cable data and stuffing tube hole data and any other information that may be helpful.

c. Study prints of various types of hangers, in order to visualize types of hangers used in different cable runs.

3. OBTAIN BLUEPRINTS COVERING ALL THE CIRCUITS AND LIST EACH CIRCUIT INDIVIDUALLY.

a. Start with the lighting circuit.

b. Locate the bulkheads in the section selected.

c. Begin with the forward bulkhead of the section and consider this as the source of the cables that enter the section.

d. When listing the cables, show the number of the frame or bulkhead of the cable source and destination.

e. Omit the local runs when laying out main runs. They are to be put in later.

f. List the cables in the following manner:

4. RE-ARRANGE THE ABOVE LISTING TO SUIT THE BRANCHING OFF OF THE CABLES.

a. Arrange the cables so that the through cables will extend to the outboard of the run. The next longest group of cables will follow the through cables.

b. Place each cable in its proper place with respect to the farthest aft.

Cables Listed to Suit Branching off of the Cables

5. MAKE A COMPOSITE LIST OF THE CABLES IN TEE ABOVE ORDER.

a. Place the through cables, light, power, I.C., fire control, and radio to the outboard of the run, and place the remainder of the cables according to their branching-off point.

Composite Listing

6. MAKE A COMPOSITE DRAWING OF THE ABOVE LISTING.

a. Obtain the following supplies:

b. Make a drawing from the composite listing, showing bulkheads, boxes, tube areas, etc.

Note: Make sure to properly name each cable.

7. MAKE A DRAWING OF THE CABLRS IN RACK AT BULKHEADS.

a. Check main wireway to determine the type of hangers to use.

b. Look up the type on blueprint.

c. Study this type carefully, noting all details.

d. Make a sketch of this type of hanger and show cables in their proper location.

8. LAY OUT TUBE AREAS.

a. Secure shipfitters print covering the bulkhead to be considered.

b. Check carefully for size of area.

c. Check to see if the tubes are put directly into the bulkhead, or if a plate is cut out.

d. Check the kind of plate (lap of insert).

e. Check the kind of tubes to be used.

f. Refer to tube and hole chart to obtain proper sizes.

g. Lay out an area on paper the proper size.

h. Arrange tubes to fit into the area, keeping as near as possible the same location as that in which the cables lay in the rack.

i. Have no crosses at the area.

j. Do not allow cables to cross one another from one side to the other. However, cables may change tiers by either dropping down or going up.

k. When the area has been properly arranged to suit the cables, make a permanent layout of the area on heavy cardboard by drawing circles the actual size and spacing of the tubes and printing the cable and tube designation within each circle.

l. In laying out cables in the machinery spaces, keep all large cables to the inboard of the rack, and all through cables on the bottom tiers.

m. In the rest of the ship, keep through cables to outboard of rack and on bottom of tiers.

n. Where possible, arrange cable grouping as shown below:

o. Maintain polarity of single-conductor cables in order to avoid magnetic loops for all D.C. circuits. Negative and positive leads should never exceed 12-inch spacing; that is, D.C. circuits should be neutralized at all times.

p. Use multi-conductor cable when practicable; that is, duplex for single phase and triplex for 3 phase.

Note: When for special reasons it is necessary to run separate phase leads, the individual leads for the single or 3-phase circuits should be kept as close together as possible throughout their lengths. They should be twisted together not greater than 16 times the pitch diameter. Single-conductor cables carrying A.X. should not be grouped in the same hangers with cables carrying D.C.

II. CABLE TYPES AND USES

TYPE SLPP AND SLPA--These letters refer to single lighting and power plain, and single lighting and power armored. This cable ranges from 4,000 to 1,500,000 circular mils in approximate cross-sectional area. The smallest size, approximately 4,000 circular mils, consists of the single-stranded conductor, a layer of 40 per cent rubber, a layer of rubber-filled tape, and a cotton braid. Type SLPA has, in addition, an outside layer of basketweave armoring.

All cable of these two types with the exception of the smallest size is made differently. These cables consist of the stranded conductor, varnished cambric insulation, rubber-filled tape, reinforced rubber sheath, rubber-filled tape, and a cotton braid. The armored variety of these larger sizes has a basketweave metal armoring in place of the cotton braid.

Plain cable is to be used in turret columns and like installations where flexibility is important. The armored type, SLPA, is used in permanently installed lighting and power leads throughout the vessel where a single conductor is required.

TYPE SRLL--This is a single-conductor, low-tension, lead-sheathed cable for radio use only.

TYPE SRHLA--This is a single-conductor, low-tension, lead-sheathed cable for radio use only.

TYPE DLPP AND DLPA--This is a duplex cable for lighting and power use, and may be obtained either plain or armored. As in the case of the single conductor of this type, the smallest size is manufactured differently from the larger sizes, The smallest size, approximately 4,000 circular mils, consists of two conductors, each one of which has a layer of 40 per cent rubber insulation and a layer of rubber-filled tape. The largest size is 400,000 circular mils. (SLPA insulation is in the same sizes, from 4,000 circular mils to 1,600,000 circular mils.) These two conductors are twisted together. Dry jute filler is used to obtain circularity of cross section. The conductors are then covered with a layer of rubber-filled tape, a layer of 40 per cent rubber, another layer of rubber-filled tape, and a cotton braid. In the case of the armored variety, a basket-weave metal armoring is used instead of the cotton braid.

The larger sizes run from 9,000 to 60,000 circular mils approximate cross-sectional area. In these sizes, each conductor is covered with varnished cambric. The two conductors are then twisted together and filled with jute, as in the smallest size described above. The conductors are then covered with a double layer of varnished cambric tape half lapped, a layer of rubber-filled tape, and a cotton braid. In the armored variety, the cotton braid is replaced with basket-weave metal armoring.

In general, duplex cable of approximately 60,000 circular mils or less is to be used in preference to two leads of the single cable. Referring to the table of limiting current capacities, note that the single cable is to be used for cable sizes larger than the 60,000 circular mil type.

TYPE DLB--This duplex, lighting, braided cable consists of two conductors, each covered with a layer of 40 per cent rubber and a layer of rubber-filled tape. The two conductors are then twisted together using dry jute as a filler. The next layer is a layer of rubber-filled tape followed by an outside covering of cotton braid. This cable should not be used for permanently installed lighting leads.

TYPE DRHLA--This duplex, high-tension, leaded and armored cable has a very high insulation resistance and is to be used only on high-tension circuits.

TYPE TRLL--This twin conductor, low-tension, lead-sheathed cable is for radio use only.

TYPE TRHLA--This triplex, high-tension, leaded and armored cable, like the duplex variety, has a very high insulation resistance and should be used only for radio work.

TYPES TLPP AND TLPA--This triplex cable is for lighting and power use. Each conductor is twisted together, using dry jute to maintain circularity of cross sections. The group of conductors is then covered with rubber-filled tape, a layer of 40 per cent rubber, a second layer of rubber-filled tape, and a cotton braid. The armored variety is covered with a basket-weave metal armoring in place of the cotton braid. The above description refers to the smallest size, approximately 4,000 circular mils, of the triplex cable. The larger sizes, from 9,000 to 60,000 circular mils, inclusive, are prepared as follows:

Each conductor is covered with varnished cambric. The three conductors are then twisted together, using dry jute as a filler. The group of conductors is then covered with a double layer of varnished cambric tape, half lapped. This is followed by a layer of rubber-filled tape, a rubber sheath, a layer of rubber-filled tape and a cotton braid. In the case of the armored variety a basket-weave metal armoring is used instead of the cotton braid.

The triplex plain cable is used for leads only in special or approved installations. The triplex armored variety is used for permanently installed lighting and power leads which require a three-conductor cable.

TYPE FLP--This is a four-conductor plain cable for lighting use only. It is similar to Type FLB except that the group of conductors is covered with a layer of rubber-filled tape, a reinforced rubber sheath, a layer of rubber-filled tape, and a cotton braid. This cable shall be used for leads only in special or approved installations. The maximum current carrying capacity is 10 amperes.

TYPE FLA--This four-conductor armored cable is for lighting use only. It is similar to Type FLP except that a basket-weave metal armoring is used instead of the cotton braid. This cable shall be used for all permanently installed lighting leads throughout the vessel which require four conductors. The maximum current-carrying capacity of this type is 10 amperes.

TYPE FPC--This is a flame-proof cable. This cable consists of a single conductor covered with an asbestos layer and an asbestos braid which has been made flame proof by a special cement.

TYPES GICP AND GICA--This is a multiple-conductor cable for general interior communication use. The smallest size consists of two conductors. Each stranded conductor is covered with a cotton thread, a layer of 40 per cent rubber, and cotton braid. The two conductors are then twisted together, using dry jute as a filler. The group of conductors is then covered with rubber-filled tape, 40 per cent rubber insulation, rubber-filled tape, and a cotton braid. The armored variety of this cable is covered with a basket-weave metal armoring in place of the cotton braid.

The larger cable for interior communication use contains 4, 7, 10, 14, 19, 22, 26, 30, 37, and 40 conductors per cable. Each conductor is prepared in the same way as the conductors in the twin cable. The conductors are then twisted together in layers. The direction of lay for successive layers of conductors is alternated. One conductor in each layer is solid color: red, black, or green. The group of conductors is covered with rubber-filled tape, reinforced rubber sheath, rubber-filled tape, and a cotton braid. The armored variety of this cable is covered with a basket-weave metal armor instead of the cotton braid.

Type GICA cable is used for all permanently installed interior communication and fire control leads which operate at a pressure less than 600 volts. The plain variety of interior communication cable is for use in the center column of turrets where flexibility is most important and as leads to instruments mounted on guns where the cable is led through the center of the gun mount.

In general, Type TPTA cable is used for all permanently installed leads for the telephone system. Type TPTP cable is used in the center column of turrets where flexibility is important and as leads to instruments mounted on guns where the cable is led through the center of the gun mount.

TYPE TCP--This is a telephone cord, plain, with two or three conductors.

TYPE TCP-1--This is an extra flexible, ship's service, two-conductor cord for connecting transmitters and receivers to the reel. Each conductor consists of 12 very fine copper strands covered with silk and copper braid. One conductor has a green and the other an orange marker thread. They are twisted together with white cotton filler cord and covered with a flexible black cotton braid. TYPE TCP-2--This is a two-conductor cord for fire control telephone use. Each conductor consists of three wires of tinned steel or bronze twisted at the center of a group of nine wires of tinned copper. This conductor is covered with cotton thread, rubber insulation, and a red or black cotton braid. One red and one black conductor are then twisted together using jute as a filler. The group of conductors is then covered with a rubber insulation and a glazed black cotton braid. TYPE TCP-3--This is a three-conductor cord for fire control telephone use. This cord consists of three conductors similar to those described above in Type TCP-2. Each conductor is covered with cotton thread and a rubber insulation, followed by a cotton braid of red, black, or yellow. One conductor of each color is used to make the cable. After three colored conductors are twisted together, they are covered with a 40 per cent rubber insulation and a glazed cotton braid.

TYPE TCS-1--This is a two-conductor type. Each conductor consists of three wires of tinned steel or bronze about which are wrapped nine wires of tinned copper. This conductor is covered with cotton thread, rubber insulation, and a red or black cotton braid. One red and one black conductor are twisted together and covered with a rubber sheath.

TYPE TCS-2--This is similar to Type TCS-1 except that it consists of three conductors, colored red, black, and yellow. Types TCS-1 and TCS-2 telephone cord are used where highest flexibility and the smallest diameter of cord are not important.

TYPE PCP--This is a portable cord, plain, and may be obtained as a two-conductor, four-conductor, or five-conductor cord. There are three sizes of the two-conductor cord; namely, 1,400, 2,600, and 4,100 circular mils.

Type PCP cable is used for leads connecting outlets to electric fixtures of the semi-portable type, such as boom, steering, anchor, peak, blinker, and running lights; also for leads connecting outlets to such fixtures as fans, portable blowers, electric tools, and portable lighting units.

TYPE PCP-1--This is the 1,400 circular mil two-conductor cord. Each conductor consists of 14 copper wires twisted together and covered with cotton and rubber insulation. The pair of conductors are then twisted together and finally covered with a tough rubber sheath.

TYPE PCP-2--This is the 2,600 circular mil cord. It is similar to type PCP-1 except that it contains 26 copper wires instead of 14.

TYPE PCP-3--This is the 4,100 circular mil, two-conductor cord. It is similar to the other two conductor cords except that each conductor consists of 41 copper wires twisted together.

TYPE PCP-4--This is a four-conductor cord, of 1,400 circular mil cross section. Each conductor is prepared the same as the conductor of Type PCP-l. The four conductors are covered with different colored cotton braid and then twisted together. The group of conductors is covered with a tough rubber sheath.

TYPE PCP-5--This is the five-conductor cord and is also a 1,400 circular mil cord, but consists of five conductors. Otherwise it is similar to Type PCP-4.

TYPE GRC--This is a multiple-conductor cable for gyro repeater use, and may be obtained with 7, 10, or 12 conductors. Each conductor consists of 14 copper wires twisted together and covered with cotton thread, rubber insulation, and a cotton tape. The whole group is then covered with a tough rubber sheath.

Type BW cable is for use where high flexibility is not required, for instrument wiring, and for miscellaneous small wiring of switchboards and panels.

TYPE BC--This is known as bell cord. Each conductor consists of 26 copper wires twisted and covered with cotton thread followed by a rubber insulation. The conductor is next covered with a braid of silk, colored green. Both conductors are then twisted together to form the bell cord. Bell cord is used as a flexible lead connecting outlets to push buttons and such other applications as may be specifically approved by the bureau. If it is desired to use three conductors, Type BC-3 may be used. This is exactly the same as Type BC-2 except that three conductors are used instead of two.

TYPE IW--This ignition wire consists of a single conductor of 19 copper wires, covered with a rubber insulation and a braid which will resist oil, gasoline, water, ozone, and weather.

This cable shall be used exclusively for wiring internal combustion engines.

TYPES SHFA, DHFA, THFA--Conductors same as L.P. type.

TYPES MHFA AND MHFP--These are the same as GICA and GICP, but insulation is the same as I.D. and THFA.

III. CABLE TYPES WITH ABBREVIATIONS

Abbreviation

Note: The prefix letter on all cables indicates the number of conductors in the cable except the "M" and "GIC" cables.

The suffix numeral on all cables except the "M" and "GIC" cables represents the size of the conductor in 1000 circular mils. On the "M" and "GIC" cables, the suffix numeral represents the number of conductors in that cable. The size of wire on all "M" and "GIC" cables is number 3 Navy or 3000 circular mils.

IV. STANDARD CONDUCTORS BEFORE INSULATING

V. COLOR CODE FOR TTHFA

New Synthetic Insulation

VI. INSTALLATION NOTES FOR ELECTRICAL EQUIPMENT
Standard Naval Practice

1. All motor controllers, distribution panels, and similar apparatus (except switchboards and switchboard panels which have special installation requirements) shall be installed at a height so that either the bottoms of the enclosing cabinets shall be not less than five feet, or the top not more than seven feet above the deck.

2. All hand-operated appliances, including distribution boxes with switches, individual switches, receptacles with switches, push buttons, jack boxes, etc., shall be installed on bulkheads at a height of not more than six feet above the deck.

3. Connection boxes, feeder connection boxes, feeder distribution boxes, feeder junction boxes and distribution boxes without switches may be installed overhead, provided the deck height does not exceed nine feet, and the minimum-head room under the appliances is not less than seven feet.

4. All controllers, panels, and apparatus shall be so installed that they are completely accessible for operation repairs, renewal of fuses, testing, maintenance, etc.

5. All watertight and explosion-proof electric wiring equipment shall be fitted with standard terminal tubes for the entrance of cables. When the equipment has aluminum cases, the terminal tubes shall be aluminum. In installing aluminum tubes in aluminum boxes, the terminal tubes shall be threaded into the boxes until the shoulder of the tube touches the side of the box. The end of the threaded part of the tube shall be flush with the inside wall of the box. The aluminum thread of box and terminal tube shall be coated with an anti-seize compound of petrolatum and zinc dust.

6. The entrance of cables through the bottom of vertically installed non-watertight appliances shall be avoided where side or top entrance is practicable and involves no undue increase in wiring. Care shall be taken, however, that the saving in weight intended by the use of such non-watertight appliances is not offset by the installation of additional cable lengths to avoid bottom entrance to the cable for such appliances. Where cables do enter the top of non-watertight fittings, standard terminal tubes shall be used.

7. Cables shall be carried into the side of such appliances so that they are maintained to their full diameter at least flush with the inside surface of the box wall.

8. Cables entering watertight appliances shall use standard terminal tubes except that where such appliances are used in connection with a non-watertight installation, cable clamps shall be used, unless modified by note No. 6.

10. The installation of lighting fixtures shall not be made until the general arrangement of all other fittings, furniture, etc., has been decided upon and they shall be in complete accordance with the final arrangement of structural material, fittings, furniture, etc., within the compartment. In cases where lighting units are installed to satisfy contemplated arrangement of structural material, fittings, furniture, etc., and such arrangement is later changed on the vessel, the location of lighting units shall be changed to suit. Fixtures shall be accessible and shall be so installed that illumination is not interfered with by ventilation ducts, pipes, cables or other overhead fittings and equipment.

11. In storeroom, issuing room, and commissary spaces, particular attention shall be given to the location of lighting units in order that these units will be in the center of aisle spaces and not on top of bins, fittings and equipment, etc., and that the maximum illumination valves may be obtained in the working spaces.

12. In crew and C.P.O. berthing spaces, lighting fixtures shall be located in the aisle between berths; however, particular attention shall be paid to the stowage of lifebelts.

13. In mess spaces, particular attention shall be given to the location of lighting fixtures so as to properly illuminate mess tables.

14. In general, all switches controlling lights shall be located near the access and shall be about four feet six inches above the deck, with the exception of the switches for blue light bulkhead lights which shall be nippled to the fixture.

15. Where switch and single receptacles or switch and double receptacles are fed from distribution boxes with switches, the switch in the distribution box shall be blanked. The switches shall also be blanked for feed to relay operated howlers, single phase indicators on control panels or for similar alarm units.

16. In connection with the installation of lighting fixtures in machinery spaces, fireroom, and other hot spaces, consideration should be given to the tightening of the supporting screws for the sockets in order to prevent the splitting of the insulation due to too much tension.

17. In congested areas and elsewhere if required, stuffing tubes shall be staggered on either side of bulkhead; that is, alternate tubes are to be located on each side of bulkhead to allow more space for welding.

19. All permanently installed cables shall be secured to decks and bulkheads by standard methods. Special attention shall be given to the support of heavy banks of cable. Where practicable and except where otherwise specified, cables shall be run on bulkheads in preference to overhead on the under side of deck.

20. Where cables pass through non-watertight bulkheads or beams of over 1/4 inch thickness, no stuffing tubes shall be used, but the holes therein shall be drilled slightly larger than the cable and the edges rounded off to prevent chafing of the leads. Where the non-watertight bulkheads or beams are 1/4 inch and under in thickness, standard or special bushings shall be used. On all non-watertight bulkheads where sharp bends occur in the cable immediately after passing through such holes, standard or special bushings shall be used.

21. In food handling or storage spaces, cable hangers shall be bracketed away from flat surfaces and the cable runs restricted to single layers, unless otherwise specifically approved, to enable spraying for insect control.

22. Main wireways and through cable runs shall be so arranged that the cable will not be disturbed by disassembly or removal of machinery.

23. Care should be exercised to avoid the grouping together cable of different voltage and phase relationship and different service application, power, interior communication, telephone, etc., in such a manner as to pile up electrical or magnetic stresses or interfere with the proper functioning of the electrical circuits involved.

24. a. If any other lead is practicable, electric cables shall not be led into or through the following spaces, nor in spaces adjacent thereto, which are ordinarily open to such spaces when powder is being handled:

b. If cables are run through the above spaces, they shall in every case be of armored type and shall be of unbroken length within the space. If led into the above spaces, they shall be of unbroken length to the fixture at which they terminate.

d. Where it is necessary to run cables along or down a bulkhead, they shall be protected against mechanical injury, if required by inspector, by a non-watertight five-pound steel casing. The casing surrounds the electric cables in magazines and other spaces in which ammunition is handled. Suitable air space shall be provided between the above protective casing, bulkhead, or deck and the cable, with openings or holes in the casing as may be necessary to ventilate the air space itself. Adequate drainage will be provided for casing located on the floor.

25. Wherever circuit trunking cable runs are installed for two electrical systems, one of which is auxiliary or secondary to the other, or emergency for the other, the trunking of the cable shall be such that the two systems are maintained as widely separated in the vessel as is possible in order to reduce the likelihood of damage to both from the same causative agency. Where multiple stations are installed to provide secondary control, in case of damage to one or more station, the cable leading to each station shall be separated as much as possible throughout their entire length.

26. Cables which are installed where they will be subjected to mechanical injury in service shall be protected within such exposure zones by suitable metal casings.

27. Where required, the protection of leads passing through decks shall be in accordance with standard methods by means of conduits (kick pipes) forming a part of the stuffing tube. Such kick pipes shall be fourteen inches in height except in special cases where a deviation from the type is specifically approved. The height of all kick pipes installed in one group shall be uniform.

28. Where eight or more cables are installed through a deck other than a weather deck, a community riser shall be provided in lieu of kick pipes. On weather decks kick pipes shall be used exclusively unless otherwise specifically approved.

29. Where four or more cables are run through decks or bulkheads with insulation, the insulation shall be cut away and short stuffing tubes used. In installations of less than four cables, stuffing tubes of a length suitable to pass through the insulation shall be used.

30. The run and grouping of cables shall be such as to avoid inaccessible pockets of sufficient size to provide harborage for rats. Cables shall be hung away from structural members parallel to the cable run that would form pockets and partially conceal spaces so that top surfaces may be readily inspected and kept clear of nesting material. Where cables pass through trunks or ducts, either the clearances of the duct or trunk shall be kept to less than one-half inch or the ends of the duct or trunk

31. All cables on bulkheads in the following areas shall be mounted so as to provide a space approximately 3/8 inch between bulkheads and cable in order to allow condensation to run down bulkhead and not collect in back of cables:

32. In connection with the installation of cables through bulkheads and decks, the cables should be arranged in such a manner that adequate inspection shall be provided between all cables in connection with the elimination of nesting material and rat harborage.

33. If any other lead is practicable, electric cables shall not be installed under such conditions or in such locations as may cause it to be subjected to excess heat. The following conditions and locations shall be considered as falling within this category:

35. In general, and except where otherwise specifically approved, cable runs shall be made along bulkheads in the lower portion of boiler room so as to take advantage of ambient temperature conditions.

36. Horizontal runs shall be utilized to the greatest extent practicable in order to reduce the tendency of the cable lubricant or saturant to migrate.

37. Where such cable runs cannot be avoided, cable leads over or in too close proximity to turbine steam heater, steam piping, electric resistors, rheostats, etc., and other heater apparatus shall be provided with suitable heat insulating barriers.

38. In general and where it is practicable to avoid same, electric cables shall not be installed adjacent to fire mains, water and steam pipes and other apparatus or piping which may cause injury to the cable by leaks, flooding or drip. Where such proximity is unavoidable, the cable shall be provided with suitable drip-proof protection overhead or other suitable barrier against water.

39. All cables exposed to radio frequency fields, also all cables entering and within radio spaces (including portable cables to deck fixtures, bracket fan, etc.) shall be of the metal-armored type or metallicly shielded throughout their entire length, the shielding to be grounded.

40.

41. In the handling of electric cable both prior to and during its installation aboard ship, care shall be taken to avoid abrasions, crushing by blows or by bending too sharply without aid of mandrel or other device, particularly where the cable is very cold. Also the contact of cables with water and/or lubricating oil or grease shall be carefully avoided. No damaged cables shall be installed and any cable damaged during or subsequent to its installation aboard ship shall be removed and replaced by satisfactory cable. The minimum safe bending temperatures are as follows:

42. Whenever electric cable is cut into lengths for the purpose of installation, all cut ends, whether on the lengths being installed or on the lengths remaining on reels or in coils, shall be sealed in a suitable manner so as to prevent the entrance of moisture into the interior of the cables via the cut ends. In this connection it cannot be too strongly emphasized that such cut ends are the most vulnerable portions of the cables and any failure to observe the necessary precautions at the proper time may result in the boxing up of moisture entailing subsequent serious hazard.

43. In the case of cable provided with a protective basket-weave metal armor, the ends of such armoring shall be secured in a suitable manner whenever the cable is cut into lengths to prevent the armor from loosening up and springing back from the cut end.

44. All cable entrances in non-watertight appliances shall be made tight against drip or vermin by the use of a suitable compound (Duxseal, Halowax aluminastic) applied to the joints between the cable and the box wall.

45. Solderless-type connectors shall be used for all flame and heat-resistant cable.

46. For solderless connectors, the cable end shall be prepared for the terminal connection by neatly turning back the insulation for the required distance, thoroughly cleaning the individual strands, and then twisting them tightly together before clamping the solderless connector.

47. All terminals for interior communication system shall be solderless type as far as practicable, except as noted below.

48. All terminals for sound powered telephone equipment shall be of the standard soldered type.

49. In connection with the use of soldered terminals, the terminal shall be tightly clamped over the prepared conductor so as to grip it solidly before soldering.

50. Cable insulation and its protective covering shall be intact close up to the terminal. Where the copper conductors have been exposed in making connections the insulation shall be renewed by carefully wrapping the conductor with an approved insulating tape, Phenolic or cord. The cable end and cable insulation shall be thoroughly saturated and sealed with insulating varnish approved for the purpose. The finished connection shall present a neat and workmanlike appearance. Leads within electrical fittings shall be bound by cord with loops separated by a distance depending on conductor size, and varnished (rubberoid-glyptal).

52. Where clamp fittings (Bureau Standard Drawing) are specified, such as used with STD junction boxes, etc., the cable ends shall be bared and the individual strands thoroughly cleaned and twisted together and then soldered to form a neat solid terminal for fitting under the clamp. In order to increase the size of the terminal thus formed in small conductors, the bared strands may be bent back on themselves before being twisted and soldered.

53. Where a connection is to be made under a screw head and the use of a standard terminal is not practicable, a loop or eye shall be formed on the cable end by baring the conductor for the required distance, thoroughly cleaning the wire strands, twisting them tightly together, bending them around a mandrel so as to form an eye of suitable size and dipping the whole eye in the solder so it will form a solid terminal integral with the cable. Graumets may be used on approval.

54. To obtain the greatest degree of compactness practicable, those types and sizes of cable having the smallest permissible radii shall be placed on the inner side of the cable group, allowing cable having larger bending radii to be placed on the outside of the group.

55. Where shorter bends are required for terminal entrances, standard angle type terminal tubes, either forty-five degree or ninety-degree type, shall be used.

56. In the case of horizontal bends of large radii, particularly in such location as might be subject to damage by personnel or by vibration, a suitable mechanical supporting member shall be employed and the cable securely attached thereto at frequent intervals.

57. Special care shall be taken to maintain proper phase relation of all wires from the switchboards to appliances, etc., that is, phase wires A, B, and C shall be similarly connected throughout their length for feeders, mains, submains, and branches.

58. In order to standardize connecting of phase wires to equipment, the following system shall be used on lighting and power cable (three wire) where color coding is used, black to be wire A; white to be wire B; and red to be wire C.

59. The bus arrangement and connection to switchboards or panels looking at the back of the switchboard or panel shall be A-B-C respectively from left to right, top to bottom, or front to back, the front being the bus nearest to the switchboard panel.

61. The terminals of rotating machines will be marked with phase designation so that when these terminals are connected to the source of supply in the same order; that is, A to A, B to B, and C to C, the rotation of the motor shall be clockwise facing the power end of the machine.

62. For counterclockwise rotation of the motor, phase wires A and B shall be interchanged.

63. No spliced connections shall be permitted in the electric plant installation.

64. All steel straps and hanger material except pads and welded studs shall be galvanized after forming. All bolts, nuts, screws, washers, etc., shall be cadium plated, or suitably painted.

65. All aluminum hangers, casings and supports shall be painted with one coat of zinc chromate primer and one coat of aluminum paint as soon as possible after forming, and a second coat shall be applied after assembly and installation on the ship.

66. All faying surfaces of aluminum alloys shall be painted with one coat of zinc chromate primer and allowed to dry, and the fittings separated from the bulkhead or deck by a canton flannel (for light work) or canvas gasket (for heavy work) soaked in zinc chromate iron oxide paint just before installing.

67. All cables shall be painted with one coat of aluminum paint, all painting being done after cables are pulled and before they are strapped down. The painting shall be accomplished by spraying.

68. All aluminum pipe shall be painted with one coat of zinc chromate primer and two coats of aluminum paint.

69. All aluminum castings are painted with one coat of zinc chromate primer and two coats of aluminum paint, and where the zinc chromate primer has been scratched or damaged due to installation, the fittings shall be retouched with zinc chromate primer before the additional coats of aluminum paint are applied.

70. Threads of aluminum pipe shall be coated with an anti-seize compound.

71. Great care shall be taken that electrical insulators are not painted, such as molded or pressed insulation of various forms, cable cleats, etc., which might introduce leakage. Care shall also be taken that gaskets, rubber packing or any jointing of watertight work are free from paint.

73. All cables shall be painted as per note No. 89, after which they may be painted to match their surroundings. If no other finishing coat is applied, an additional coat of aluminum paint shall be applied as a final finish.

74. All electrical fittings, fixtures, etc., except molded type (See note No. 77) shall be painted after installation to match their surroundings.

75. All emergency lighting fixtures shall be painted green, except those on molded insulation. Since the latter may not be painted they shall be marked as emergency lighting fixtures by painting a green ring on the structural deck or spring hanger support adjacent to the fixture, or by providing a suitable name plate marked "Emergency Lighting" on or adjacent to the fixture.

76. All ungalvanized steel work in back of cables or boxes shall be painted with one coat of aluminum paint in addition to the priming coat, before the installation of cable.

77. Fixtures of molded insulation shall not be painted other than as required by the following subnotes:

78. Name plates and tags shall be located in readily accessible positions where they can be read at all times without danger to personnel.

79. When a name plate is mounted on a panel or switchboard, it shall be placed in close proximity to the equipment to which it refers and generally either directly above or directly below it.

82. Cables shall be tagged as close as practicable to the point where the terminals connect to the panels or piece of equipment.

83. Cable tags shall be marked with the feeder, main, submain, or branch circuit designation for lighting and power cables and with the circuit designation and cable number for interior communication and fire control system.

84. Name plates shall be fastened securely to such parts of machinery or equipment as ordinarily will not be renewed during their service life. The attachment shall be by means of screws, self-threading screws, or steel drive pins.

85. All electrical appliances in the nature of switches, control apparatus, etc., located in another compartment or at a distance from the unit controlled shall be clearly marked with a name plate showing the use and operation of same and the location and ship's designation of the unit controlled.

86. Where power and lighting leads run into a distribution panel the main lugs and buses shall be stamped with the circuit letter and number, and the phase designation. Suitable name plates shall be provided adjacent to the switch handles for all branch circuits on the panel itself, and on the outside of the panel box cover for feeders and panel designation. Terminal lugs shall be marked with the circuit letter and number, and also with the phase designation in the case of three-conductor cables.

87. The terminals on back of all switchboards shall be marked with the circuit letter and number. Where buses are provided, this marking may be stenciled on the bus.

88. The buses of switchboards need not be marked with the polarity or phase indication as this information will be self-evident from the location of the buses, except that' when a set of bus bars do not constitute a full three-phase supply (a single-phase tap) the buses shall then be marked.

89. All terminal lugs for cables on switchboards and distribution panels shall be marked with a phase marking, A, B, C, (for AC) or plus or minus (for DC).

90. Projecting bus structure in the rear of switchboard shall be protected by insulating material barriers, to prevent personnel from being thrown against live buses by movement of vessel.

92. All interior communication and fire control wire terminals shall be stamped with circuit markings and wire number as shown on the various elementary diagrams, so as to clearly identify the wire and its function in the circuit. In addition to the markings required above, all wire terminals for call Bell Systems (circuit A and E) shall have on the reverse side the number of the cable which contains the leads to which the terminal is marked as shown on the Isometric diagram of the system. This reverse marking shall be made only in the case of leads emanating from connection boxes or similar conditions, such as a single lead to a push button or bell where the cable number is evident.

93. Blown fuse indicators shall be provided for all fuses on fire control, inter communication, A.C.O. switchboards, all control circuits on main switchboards, for vital operation such as voltage regulators, circuit breakers, etc., and on all three-phase mains and submains on power and lighting circuits.

94. Care shall be exercised that all permanently installed motors other than bracket fans are thoroughly grounded.

95. Electrical fittings of aluminum alloy where mounted on steel decks and bulkheads, plates, hangers, etc., shall have between faying surfaces canvas washers soaked in raw linseed oil or Phenolic Resin varnish and painted with zinc white paste. Electrical fittings of molded Phenolic material when similarly mounted shall have between faying surfaces felt or duck washer impregnated with Phenolic Resin varnish.

Note: All the foregoing notes are standard Naval practice.

APPENDIX

I. Symbols Used in Marine Electrical Blueprints

II. Color Codes Used in Marine Electrical Blueprints and Wiring

APPENDIX

I. Symbols used in marine electrical blueprints

Navy Type

Telephone Twisted Pair Code #22

Twisted pair color code: When furnished as twisted pair, the following color code shall apply:

Capacitance. The capacitance of a 50-foot twisted-pair sample, after first drying for 4 hours at 30° C., and then followed by exposure for 24 hours to 30° C. and 90 per cent relative humidity, shall not exceed 2500 micro-microfarads at 1000 cycles per second. When the capacitance measurements are made, the sample shall be removed from the coil frame used for humidification purposes, and tested either in a straight length or in such position as to avoid errors due to too close proximity of any one portion of the test specimen to any other portion (such as might be introduced were adjacent loops to touch in a closely coiled specimen).

Telephone Twisted Pair Code #22 (continued)

Insulation resistance. The direct current insulation resistance (between conductor) of a 50-foot twisted-pair sample, after exposure for 24 hours to conditions of 30° C. (86° F.) and 90 percent relative humidity, shall be not less than 1,000 megohms. The insulation resistance measurements shall be made immediately following the capacitance measurements.

#22 Single Wire Telephone Code. Single conductors shall be furnished in the following colors, as required: