New Cable Tag System

Other letters and numbers are used with these basic letters to further identify the cable and complete the designation. Common markings of a power sys- tem for successive cables from a distribution switch- board to load would be as follows: feeders, FB-411; main, l-FB-411; submain, 1-FB-411A; branch, 1-FB-411A1; and sub-branch, l-FB-411-A1A. The feeder number 411 in these examples shows the system voltage. The feeder numbers for a 117- or 120-volt system range from 100 to 190; for a 220-volt system, from 200 to 299; and for a 450-volt system, from 400 to 499. The exact designation for each cable is shown on the ship’s electrical wiring prints. NEW CABLE TAG SYSTEM.—The new system consists of three parts in sequence; source, voltage, and service, and where practical, destination. These parts are separated by hyphens. The following letters are used to designate the different services: C Interior communication D Degaussing G Fire control K Control power L Ship’s service lighting N Navigational lighting P Ship's service power R Electronics CP Casualty power EL Emergency lighting EP Emergency power FL Night flight lights MC Coolant pump power MS Minesweeping PP Propulsion power SF Special frequency power Voltages below 100 are designated by the actual voltage; for example, 24 for a 24-volt circuit. For voltages above 100, the number 1 shows voltages between 100 and 199; 2, voltages between 200 and 299; 4, voltages between 400 and 499, and so on. For a three-wire (120/240) dc system or a three-wire, three-phase system, the number shows the higher voltage. The destination of cable beyond panels and switchboards is not designated except that each circuit alternately receives a letter, a number, a letter, and a number progressively every time it is fused. The destination of power cables to power-consuming equipment is not designated except that each cable to such equipment receives a single-letter alphabetical designation beginning with the letter A. Where two cables of the same power or lighting circuit are connected in a distribution panel or terminal box, the circuit classification is not changed. However, the cable markings have a suffix number in parentheses indicating the section. For example, figure 6-1 shows that (4-168-1)-4P-A(1) identifies a 450-volt power cable supplied from a power distribution panel on the fourth deck at frame 168 starboard. The letter A shows that this is the first cable from the panel and the (1) shows that it is the first section of a power main with more than one section. The power cables between generators and switchboards are labeled according to the generator designation. When only one generator supplies a switchboard, the generator will have the same number as the switchboard plus the letter G. Thus, 1SG identifies one ship’s service generator that supplies the number 1 ship’s service switchboard. When more than one ship’s service generator supplies a switchboard, the first generator determined according to the general rule for numbering machinery will have the letter A immediately following the designation. The second generator that supplies the same switchboard will have the letter B. This procedure is continued for all generators that supply the switchboard, and then is repeated for succeeding switchboards. Thus, 1SGA and 1SGB identify two service generators that supply ship’s service switchboard 1S. Phase and Polarity Markings Phase and polarity in ac and dc electrical systems are designated by a wiring color code as shown in 6-3