(2) The rating or setting of a branch circuit overcurrent device shall be not more than 25 percent of that of the feeder overcurrent device. (f) Cable. All cable used in connection with watertight door system feeder circuits or branch circuits shall be leaded and armored or impervious sheathed and armored. (g) Existing vessels. (1) Existing arrangements, materials, and facilities previously approved but not meeting the applicable specifications or requirements set forth in paragraphs (b) through (f) of this section may be continued in service so long as they are maintained in good condition to the satisfaction of the Officer in Charge, Marine Inspection. Minor repairs and minor alterations may be made to the same standards as the original installation provided that in no case will a greater departure from the standards of paragraphs (b) through (f) of this section be permitted than presently exist. (2) All new installations or major replacements shall meet the applicable specifications or requirements for new vessels. § 111.65-35 Special requirements for fire screen door holding and release systems-(a) Application. When an electric fire screen door holding and release system is installed in compliance with the requirements of Part 72 of Subchapter H (Passenger Vessels) of this chapter, the provisions of this section, with the exception of paragraph (e) of this section shall apply to all installations contracted for on or after November 19, 1952. Installations contracted for prior to November 19, 1952, shall meet the requirements of paragraph (e) of this section. (b) Definitions. (1) The term "fire screen door" will be used in this section to designate any self-closing door required to comply with § 72.05-25 (b) of Subchapter H (Passenger Vessels) of this chapter. (2) The term "fire screen holding device" will be used in this section to designate any device designed and installed for the purpose of holding open a fire screen door. (3) The term "local control station" will be used in this section to designate any manually operated device installed adjacent to a fire screen door for the purpose of releasing the door so that the fire screen door self-closing mechanism may close the door. (4) The term "central control station" will be used in this subpart to designate any manually operated device installed to release the fire screen doors from the wheelhouse or fire control room. (c) General. (1) The fire screen door holding and release system requirements contained in this section presuppose that the fire screen doors will be held open by electromagnets, door release being effected by deenergizing the electromagnets. (2) The Commandant may accept any other means for fire screen door holding and releasing not less effective than the electromagnetic type covered by this subpart. (d) General requirements. (1) The fire screen door holding and release sy tem shall consist of an electromagnet for each fire screen door, a self-aligning armature plate on each door to be seized and held by the electromagnet when the fire screen door is fully open, a contra switch located adjacent to the door to interrupt the supply potential to the electromagnet, and a central control located in the wheelhouse or fire control room to interrupt remotely potential to all holding magnets. (2) The fire screen door holding circuit shall be arranged so that loss of potential from any cause will release the doors, except that momentary interruptions of the circuit that may result from the operation of automatic bus-transfer devices in connection with the emergency lighting and power system, will not release the doors. (3) The central control station shall consist of an enclosed switch, circuit breaker, or magnetic contactor of ample rating to interrupt the connected load The switching unit shall be externally operative and maintaining in both the "hold doors" and "release doors positions. (4) The local control station shall consist of an enclosed externally operative fused switch having a rating of not less than 10-T amperes, 125 volts, and may be either the momentary contact type or the maintaining contact type A single door holding magnet shall be connected to the fuse end of this local control station. Where several doors are in close proximity to each other, a single local control station switch of ample rat ing may be used to release simultaneously these several doors. (5) A door holding electromagnet shall be designed for a nominal pull of approximately 200 pounds. When the arrangement of the electrical supply involves transfer relays to transfer the supply from a normal to a temporary source, a door holding electromagnet shall be designed so that, with a pull on the armature of 110 pounds, the armature will be held in the sealed position for approximately 4 second after the circuit to the electromagnet is opened. The electromagnet shall be designed for continuous duty in an ambient temperature of 50 degrees C. with a temperature rise by thermometer measurement of not more than 55 degrees C. for Class A insulation nor more than 75 degrees C. for Class B insulation. The electromagnet coil shall be vacuum impregnated and the magnet enclosure shall be either drip-proof or watertight. (6) The source of power for the fire screen door holding and release system shall be the emergency lighting and power system as required by Subpart 112.15 of this subchapter. (7) On large vessels where the closing of all fire screen doors simultaneously would seriously interfere with fire-fighting operations or with the evacuation of passengers, it is recommended that the fire screen door release system be subdivided into several circuits. The circuits shall be arranged so that it will be possible to isolate any compartment in which a fire is reported by a sufficient number of closed fire screen doors effectively to stop all draft to the fire area. An effective draft stop will entail closing: (i) All fire screen doors in the area between the main vertical zone bulkheads immediately forward and aft of the fire area; (ii) All fire screen doors in the main vertical zone bulkheads immediately forward and aft of the fire area; and, (iii) All fire screen doors in the next adjacent main vertical zones, forward and aft of the fire area. The fire screen door tripping arrangement shall be specifically approved for each vessel. (e) Existing vessels. Fire screen door holding and release systems on vessels contracted for prior to November 19, 1952, shall meet the requirements covered in this paragraph. (1) Existing arrangements, materials, and facilities previously approved will be considered satisfactory so long as they are maintained in good condition to the satisfaction of the Officer in Charge, Marine Inspection. Minor repairs and minor alterations may be made to the same standard as the original installation. (2) All new installations or major replacements shall meet the applicable specifications or requirements for new vessels. § 111.65-40 Special requirements of electric power-operated lifeboat winches—(a) Application. The provisions of this section, with the exception of paragraph (i) of this section, shall apply to all vessels contracted for on or after November 19, 1952. The provisions of paragraph (i) of this section, shall apply to all vessels contracted for prior to November 19, 1952. (b) General. The provisions of this section supplement the requirements of Subpart 160.015 of Subchapter Q (Specifications) and Subpart 75.30 of Subchapter H (Passenger Vessels) and Part 94 of Subchapter I (Cargo and Miscellaneous Vessels) of this chapter. require (c) General construction ments. (1) Control and power circuit switches and motor controllers installed in conjunction with lifeboat winches shall be of types specifically approved for use with lifeboat winches. (2) Switches and motor controllers shall be of a design not likely to be adversely affected by corrosion of the working parts. Particular attention shall be given to hinged parts of contactors and relays. Structural parts, such as the enclosing cases, if not constructed of corrosion-resistant materials, shall be given a durable corrosionresistant finish. (3) Insulating materials shall be limited to those which exhibit the lowest relative water absorption and/or the least effect of such water absorption upon the dielectric properties consistent with the other necessary characteristics. (4) Where gaskets are used to provide a water seal between parts of an assembly, the gasket shall be secured in place in such a manner as to prevent its falling out or becoming loose when the unit is disassembled. (5) Holes in the walls of equipment housings for the purpose of providing means for the attachment of parts on the interior thereof, or for securing covers and the like, shall not penetrate the total thickness of the housing wall. (6) Totally enclosed units shall be provided with a needle valve or with at least one hole closed by a 1/4 inch pipe plug for draining condensed moisture. The valve or hole shall be located at the bottom, or as near the bottom as practicable, of the enclosure in order that it may drain the enclosure satisfactorily. (7) Main line emergency disconnect switches, when installed in a location accessible to passengers, shall be provided with means whereby the switch can be locked in the open-circuit position by means of a padlock or the equivalent. The switch shall have no provisions for locking in the closed-circuit position. (d) Detail construction requirements (1) Enclosures. Each enclosure for motor controller and switching devices, when installed in locations exposed to the weather, shall be capable of meeting the test requirements of paragraph (e) of this section. (2) Electrical clearances. The minimum creepage and air clearance distance between live parts of different polarity of motor controllers, master switches, and control circuit limit switches shall be not less than the values shown in Table 111.65-40 (d) (2). It is desirable to exceed these values where possible. The electrical clearances for power circuit limit switches and main line emergency disconnect switches shall be not less than the general requirements for such devices given in this part. (3) Motors. Motors shall be of watertight construction in accordance with the general requirements of this part. TAPLE 111.65-40 (d) (2)-MINIMUM SPACINGS IN INCHES gaskets or sealing compounds, or that have been painted, shall be broken and reassembled three times; this procedure also applies to doors and to cover plates There shall be no leakage of water into the enclosure after it has been subjected to one of the following methods of submergence for a period of five continuous minutes: (i) The enclosure shall be submerged in water to such a depth that the highest point of the enclosure in its normally mounted position is under a three-foot head; or (ii) The enclosure shall be submerged in water at least 3 inches at the highest point in an open tank. Sumcient vacuum shall then be applied to the inside of the enclosure to produce an external pressure equivalent to a 3-foot head of water. (2) The following additional test shal be conducted immediately after either of the above tests, and while the enclosure is still submerged. An internal air pressure shall be applied for a period of 5 minutes equal to 112 pounds per square inch, plus a pressure equivalent to the depth of submergence. (3) Under these tests the enclosure will be considered spraytight if no water is found inside the enclosure, and if no air bubbles are seen to emerge. Where a shaft enters the enclosure, the shaft shall be operated twice while submerged (4) The following formula may be used to determine the necessary vacuum M=0.074 (12H-W) where: M=vacuum in inches of mercury. (f) Wiring of lifeboat winch components. (1) When the motor controller of a lifeboat winch power unit is located adjacent to the winch, the main line emergency switch shall disconnect al parts of the lifeboat winch power uni including the motor controller and limit switches, from all sources of potential Any other power circuit switches employed shall be connected in series with the main line emergency switch and ahead of the motor controller. The main line emergency switch shall serve as the motor and controller disconnect required by the general requirements of this part, and shall have a horsepower rating not less than that of the winch motor. (2) When the motor controller of a lifeboat winch power unit is remotely located with relation to the winch, a switch shall be provided at the controller arranged to disconnect the entire winch electrical installation from all sources of potential. In such cases, the main line emergency switch shall be connected in series with this circuit disconnect switch and ahead of the power circuit limit switches, when employed, and ahead of the motor controller. (3) Davit arm limit switches, whether connected in the power circuit or in the control circuit, shall disconnect all ungrounded conductors of the circuit controlled. (4) Where one motor is used with two winches, a main line emergency switch, a clutch interlock switch, and a master switch shall be provided for each winch, except that a single main line emergency switch located in accordance with subparagraph (5) of this paragraph with respect to both winches will be accepted. The main line emergency switches shall be connected in series ahead of the motor controller. The master switches shall be connected in parallel and each in series with the corresponding clutch interlock switch for that winch. The clutch interlock switches shall open the circuit to its master switch except when the power unit is clutched to the associated winch. Means shall be provided to prevent the power unit from being clutched to both winches simultaneously. (5) Typical lifeboat winch wiring diagrams and arrangement drawings are shown on Figures 111.65-40 (f) (5) (i) through 111.65-40 (f) (5) (iv), the arrangement of the equipment shown being diagrammatical. The fact that some show direct current motors and some show alternating current motors has no particular significance. In actual installations the main line emergency disconnect switch shall be so located as to be adjacent to the master switch; within reach of the winch operator; in a position accessible to the person in charge of the boat stowage; and in a position, for gravity davit installations, from which the movement of both davit arms can be observed as they approach the final stowed position. Special consideration will be given to other arrangements where complete compliance with these location requirements cannot be met. (g) Procedure for approval of lifeboat winch electrical installations and equipment (1) Switches. Manufacturers of master switches, limit switches, and main line emergency disconnect switches desiring to qualify their products for use in connection with lifeboat winch installations shall submit for review detail assembly drawings of the unit, identifying each part used in the assembly and the material specification, including finish, if any, of each part. After the detail assembly drawings have been reviewed sample units may be requested for testing. Units found to comply with the requirements of this section will be listed by the Coast Guard as being satisfactory for use as lifeboat winch auxiliary equipment. (2) Motor controllers. Manufacturers of motor controllers desiring to qualify their products for use in conjunction with lifeboat winch installations shall submit for review detail assembly drawings and material lists of the enclosing cases to be furnished, and detail assembly drawings and material lists and/or samples of contactors, relays, resistors and other motor controller components to be employed. For each installation of lifeboat winch motor controllers there shall be submitted for approval a drawing showing the enclosure outline, front view assembly, wiring diagram, and material list, together with the name or other identification of the vessel on which the motor controllers will be installed. No general approval of motor controllers will be given. (3) Motors. For each installation of lifeboat winch motors, plans as required by § 111.05-5 shall be submitted, together with the name or other identification of the vessel on which the motor will be installed. No general approval of motors will be given. (4) Shipboard installation drawing. For each shipboard installation of electric power-operated lifeboat winches, an elementary wiring diagram and isometric or deck wiring diagram as required by § 111.05-5 shall be submitted. (h) Testing of lifeboat winch electrical equipment. The electrical equipment shall be given periodic inspections and tests as required by Part 78 of Subchapter H (Passenger Vessels) and Part 97 of Subchapter I (Cargo and Miscellaneous Vessels) of this chapter. |