Section 1 Electrical Equipment

101. General

1. Application

(1) The requirements of this Section apply to the electrical equipment installed in the unit.

(2) The electrical equipment other than that used solely for production operation is to comply with relevant requirements in Pt 6, Ch 1 of Rules for the Classification of Steel Ships in addi- tion to the requirements of this Section.

(3) The electrical equipment used solely for production operation is applied only for the unit with Production notation specified in Ch 2.

2. Codes and standards

In the case of items not specified in this Chapter, API RP 14FZ or equivalent recognised standards such IEC.

3. Condition of inclinations

The emergency generator and its prime mover and any emergency accumulator battery are to be designed to function at full rated power when upright and when inclined up to the maximum angle of heel in the intact and damaged condition, as determined in accordance with Ch 4 of Rules for the Classification of Mobile Offshore Drilling Units. However, in no case need the equipment be designed to operate when inclined more than:

(1) 25° in any direction on a column-stabilized;

(3) 22.5° about the longitudinal axis and/or when inclined 10° about the transverse axis on a ship type unit.

102. Design

1. Installation and protective inclosure

Electrical equipment and enclosures are to be provided with a degree of protection suitable to the environment or hazard in which they are located, in accordance with Pt 6, Ch 1 of Rules for the Classification of Steel Ships or API RP 14FZ.

2. Selection of materials

Materials of construction are to be selected that are suitable for their intended service and location.

3. Earthing of electrical equipment

(1) Fixed electrical equipment

(A) All electrical equipment with metallic enclosures, whose arrangement and method of in- stallation does not assure positive grounding to the metal hull or equivalent conducting body, is to be permanently grounded through a separate conductor, and protected against damage.

(B) Where separate grounding conductors are required, they are to be in accordance with API RP 14FZ.

(C) Systems designed to other recognized standards are to comply with such standards, but in

no case are the separate grounding conductors to be of a cross-sectional area of less than indicated in Table 10.1.

(2) Lightning protection

Equipment and structure are to be protected against lightning damage in accordance with NFPA 780 or other recognized standard.

Table 10.1 Sizes of Earthing Conductor

Over 2.5 mm

4. Earthing of electrical system

(1) Where electrical systems are used solely with API RP 14FZ.

for process facilities, system grounding is to comply

(2) If the unit has integral hull tanks containing liquids with a flash point not exceeding 60 °C , a grounded distribution system is not to be used, except for the following:

(A) Grounded intrinsically safe circuits

(B) Power supplied control circuits and instrumentation circuits where technical or safety reasons preclude the use of a system without a grounding connection, provided the current in the hull is limited to 5 Amperes or less in both normal and fault conditions.

(C) Limited and locally grounded systems, provided any possible resulting current does not flow directly through any hazardous areas.

(D) Alternating current power networks of 1 kV root mean square and over, provided any possi- ble resulting current does not flow directly through any hazardous areas.

(3) Ground return path through the hull

The metal structure of an offshore installation is not to be used as a normal current return for the electrical distribution system, except for the following systems:

(A) Impressed current cathodic protection

(B) Limited and locally grounded systems for battery systems for engine starting having a one-wire system and the ground lead connected to the engine

(C) Grounded intrinsically safe circuits

5. Distribution and circuit protection

(1) General

(A) All ungrounded conductors and the devices and circuits which they serve are to be protected against over-current.

(B) Protective devices are to be provided to guard against overload and short circuit currents,

and to open the circuit if the current reaches a value that will cause excessive or dangerous temperatures in the conductor or conductor insulation.

(2) Motor controllers

Motor starting and control installations, including overload protection and short circuit protection, are to be in accordance with API RP 14FZ.

103.

Rotating machinery

1. General

Motors and generators are to be designed, manufactured and tested to NEMA Standard MG-1 or KS C IEC 60034 for performance, manufacture, protection, and construction.

2. Temperature rating

(1) Equipment is to be selected for the rated temperature higher than the specified ambient temperature. If equipment is intended to be used in a space where the equipment’s rated tem- perature is below the specified ambient temperature of the space, it is to be used at a derated load.

(2) The assumed ambient temperature of the space plus the machine’s actual temperature rise at its derated load is not to exceed the machine’s total rated temperature (rated temperature of the machine plus rated temperature rise).

3. Moisture condensation protection

(1) Generators and motors are to be provided with means, such as space heater, etc., to prevent ac- cumulation of moisture and condensation when they are idle for appreciable periods.

(2) The space heaters are to be capable of being electrically isolated.

4. Temperature detection

Generators larger than 500 kVA are to be provided with at least one embedded temperature detector per phase, at the hot end of the stationary winding, with temperature indication at a manned location.

104. Transformers

1. General

(1) Each power transformer is to be provided with a corrosion resistant nameplate indicating the name of the manufacturer and all pertinent electrical characteristics.

(2) They are to be constructed and tested to ANSI C57 or equivalent.

(3) Transformers are to be protected in accordance with API RP 14FZ, Section 8.

2. Transformer supplying services other than production operation

In addition to the above, transformers supplying services other than oil or gas production are to be selected, installed, and protected in accordance with their environmental conditions and Pt 6, Ch 1, Sec 6 of Rules for the Classification of Steel Ships.

105. Switchgear

1. Application

Main and emergency switchboards, power and lighting distribution boards, motor control centers and motor controllers, and battery charging panels, are to be designed, constructed, and tested in accord- ance with the provisions of this Article.

2. Construction, assembly and components

(1) Enclosures

(A) Enclosures and assemblies are to be constructed of steel or other suitable incombustible, moisture-resistant materials, and reinforced as necessary to withstand the mechanical, elec- tro-magnetic and thermal stresses which may be encountered under both normal and short circuit fault conditions.

(B) Enclosures are to be of the closed type.

(C) The degree of the protection is to be appropriate for the intended location according to 102.

1.

(D) All wearing parts are to be accessible for inspection and be readily renewable.

(2) Bus bars

(A) Bus bars are to be sized and arranged so that the temperature rise under the most severe loading conditions will not affect the normal operation of electrical devices mounted in the switchboard.

(B) Bus bars and circuit breakers are to be mounted, braced, and located to withstand thermal effects and magnetic forces resulting from the maximum prospective short circuit current.

(C) Bolted bus bar connections are to be suitably treated (e.g., silver plating) to avoid deterio- ration of electrical conductivity over time. Nuts are to be fitted with means to prevent

loosening.

(D) Soldered connections are not to be used for connecting or terminating any cable of 2.5 mmË

or greater. These connections are to be made with of soldered lugs or equivalent.

(E) Minimum clearances and creepage distances between live parts of different potential are to

be in accordance with API RP 14FZ or Table 10.2.

Table 10.2 Clearance and Creepage Distance for Switchboards, Distribution Boards,

Chargers, Motor Control Centers and Controllers

(3) Circuit breakers

(A) Circuit breakers are to be designed, constructed, and tested to ANSI C37, NEMA AB-1, KS C IEC 60947-2, or other recognized standard. The certificates of tests are to be submitted upon request by the Society.

(B) Circuit breakers are to have sufficient breaking and making capacities as specified in the

short circuit calculation.

(C) Isolation.

(a) Circuit breakers are to be mounted or arranged in such a manner that the breakers may be removed from the front of the switchboard, without first de-energizing the bus bars to which the breakers are connected.

(b) Draw-out or plug-in type circuit breakers that are arranged in such a manner that the breaker may be removed from the front without disconnecting the copper bus or cable connections, are acceptable for this purpose.

(c) Alternatively, an isolation switch may be fitted upstream of the breaker.

(4) Fuses

(A) Fuses are to be designed, constructed, and tested in accordance with UL 248 or IEC 60269 or other recognized standard. The certificates of tests are to be submitted upon request from

the Society.

(B) The requirements of 3 (3) (B) and (C) above are applicable.

(C) Where disconnecting means are fitted, they are to be on the supply side.

(D) If the switch is not rated to interrupt the circuit under load, it is to be provided with inter- lock to prevent opening until the load is de-energized.

(5) Internal wiring

(A) Internal instrumentation and control wiring is to be of the stranded type and is to have flame-retarding insulation. They are to be in compliance with a recognized standard.

(B) In general, internal instrumentation and control wiring is to be protected against short circuit and overload, with the following exceptions:

(a)

Generator voltage regulator circuits

(b) Generator circuit breaker tripping control circuits, and

(c)

Secondary circuit of current transformer

These circuits, however, except that of the current transformer, may be fitted with short cir- cuit protection only.

(C) Terminals

(a) Terminals or terminal rows for systems of different voltages are to be clearly separated from each other, and the rated voltage is to be clearly marked.

(b) Each terminal is to have a nameplate indicating the circuit designation.

(6) Circuit identification

Identification plates for feeders and branch circuits are to be provided, and are to indicate the circuit designation and the rating or settings of the fuse or circuit breaker of the circuit.

3. Switchboards

(1) In addition to the 105. 2, main and emergency switchboards are to comply with this Paragraph.

(2) Bus bars

Bus bars for switchboards supplied by generators are to comply with API RP 14FZ.

(3) Power generation switchboards

At minimum, the following equipment and instrumentation are to be provided for switchboards associated with power generation:

(A) Voltage regulators

(B) Synchronizing controls

(C) Synchronizing relay

(D) Ground fault detection

(E) Prime mover speed control

(F) Ammeter with selector switch arranged to measure each phase

(G) Voltmeter with a selector switch

(H) Frequency meter

(I) Watt meter

(J) Space heater pilot lamp ‒ where required

(K) Stator winding temperature indicator (500 kVA and larger generators)

4. Motor controllers

(1) In addition to the 105. 2, motor controllers are to comply with this Paragraph.

(2) Overload and under-voltage Protection

Overload protection and low-voltage protection, if provided in the motor controllers, are to be in accordance with API RP 14FZ, or other recognized standard.

(3) Disconnecting Means

(A) A circuit-disconnecting device is to be provided for each motor branch circuit so that the motor and the controller may be isolated from the power supply for maintenance purposes.

(B) The circuit-disconnecting device is to be operable externally.

5. Battery charging panels

(1) In addition to 105. 2, battery chargers are to comply with this Paragraph.

(2) Battery charger

Except when a different charging rate is necessary and is specified for a particular application, the charging facilities are to be such that the completely discharged battery can be recharged to 80% capacity in not more than 10 hours.

(3) Reversal of charging current

An acceptable means is to be installed, such as reverse current protection, to prevent the battery charger component failure from discharging the battery.

(4) The following Instrumentations are to be provided

(A) Disconnect switch for power supply to the charge

(B) Indicator light connected to the downstream side of the disconnect switch in (A)

(C) Means for adjusting the voltage for charging

(D) Voltmeter to indicate the charging voltage

(E) Ammeter to indicate the charging current

6. Switchgear supplying services other than production system

Main and emergency switchboards, power and lighting distribution boards, motor control centers and motor controllers, and battery charging panels that are used to supply services other than production

systems, are to comply with Pt 6, Ch 1 of dition to this Article.

Rules for the Classification of Steel Ships. in ad-

106. Wire and cable construction

1. General

All wires, cables, conduit fittings and wiring devices are to be IEEE, ICEA, IEC, or other recognized standards.

2. Conductor type

constructed in accordance with

Conductors are to be of copper, and stranded in all sizes, and are to be in accordance with API RP 14FZ or other recognized standards, but in no case are they to be less than the following in cross sectional size:

(1) 1.5 mmË

(2) 1.0 mmË

for motor feeder and branch circuit cables for power lighting and control cables

(3) 0.5 mmË for essential or emergency signaling and communications cables, except for those as- sembled by the equipment manufacturer, and

(4) 0.375 mmË for telephone cables for non-essential communications services, except for those as- sembled by the equipment manufacturer.

3. Insulation

(1) Conductor insulation is to be rated suitable for a minimum operating temperature of 75°C in wet environments.

(2) In addition, insulation rating is to be at least 10°C higher than the maximum ambient temper-

ature that the conductor can encounter at its service location.

4. Cable flame retardancy

(1) All electric cables are to be at least of a flame-retardant type complying with the following:

(A) Cables constructed in accordance with IEEE, ICEA, IEC, or other recognized standards, are to comply with the flammability criteria of IEEE Std. 45 or KS C IEC 60332-3-22.

(B) Cables constructed to IEEE Std. 45 are to comply with the flammability criteria of that

standard.

(C) Cables constructed to KS C IEC 60092 series are to comply with the flammability criteria of IEC Publication 60332-3-22.

(2) Consideration will be given to special types of cables, such as radio frequency cables, which do

not comply with the above requirements.

5. Fire resistant property

When electric cables are required to be fire-resistant, they are to comply with the requirements of KS C IEC 60331 series.

107. Cable support and installation

1. Mechanical protection

For cables which are not equipped with metal armor or metal sheathing, installation in rigid con- duit or similar structural protection is to be utilized if such cable is employed near walkways, at deck level, near hoist or crane laydown or work areas, or where equipment maintenance work must be accomplished in a constrained area.

2. Splicing

(1) General

(A) Electrical cables are to be installed in continuous lengths between terminations. However, approved splices will be permitted for cables of exceptional length, to facilitate their installation.

(B) The location and particulars of the splices are to be submitted to the Society for review.

(2) Construction

(A) Cable splice is to be made of fire-resistant replacement insulation equivalent in electrical and thermal properties to the original insulation.

(B) The replacement jacket is to be at least equivalent to the original impervious sheath, and is to assure a watertight splice.

(C) Splices are to be made using the splice kit, which is to contain the following:

(a)

Connector of correct size and number

(b) Replacement insulation

(c)

Replacement jacket

(d) Instructions for use

(D) All cable splices are to be type approved before use.

108. Power source requirements

1. General

(1) The governmental regulations may require reserve main power or an emergency power source in excess of these requirements.

(2) Where the main power source is used to supply services other than production systems, the

main power source is to comply with Pt 6, Ch 1 of Rules for the Classification of Steel Ships.

(3) Where the Flag Administration permits, the minimum number of required main power sources

may be reduced to one source.

2. Unmanned facilities

(1) The main power source is to be sufficient to maintain the maximum intended operational loads of the unit, without need to use the emergency source of power.

(2) An emergency power source, independent of the unit’s main power, is to be sufficient to supply

services for navigational aids as required by the cognizant Coastal Authority, but not for less than four days.

3. Manned facilities

(1) The main power source is to be sufficient to maintain the maximum intended operational load of the unit.

(2) Emergency power

(A) An emergency source of power for systems vital to safety, fire fighting, and protection of personnel, is to be provided.

(B) Where an emergency power supply has been provided for classification/flag state purposes, this source may also be used to provide emergency loads in production areas, provided the emergency source of power is adequately sized to supply all of the connected loads.

(C) Fire pump

(a) If both fire pumps required by Ch 8, 302. 1 of these Rules are electric motor driven, one of these pumps is to be powered by the emergency source of power.

(b) The emergency source of power is to have sufficient fuel for at least 18 hours of fire

pump operation.

(D) Other loads

The emergency source of electrical power is to be capable of supplying simultaneously at least the following services for the periods specified hereinafter:

(a)

Fire detection : 18 hours

(b) Gas detection : 18 hours

(c)

Communication : 18 hours

(d) ESD system (if electric) : 18 hours

(e)

(f)

Paging and alarm system : 18 hours

Emergency lighting from all spaces to all alternative egress points : 18 hours

(g) Electric blowout preventer control system

(h) Navigational aids: As required by the applicable Coastal Authority, but not less than 4 days

109. Emergency source of power

1. An emergency source of power as required by 108. may be supplied by an emergency generator or batteries, in accordance with API RP 14FZ.

2. Installations supplying services other than production systems are to be in accordance with Pt 6, Ch 1 of Rules for the Classification of Steel Ships.

110. Battery systems

1. Battery installations are to comply with API RP 14FZ.

2. Ventilation of battery rooms is to be separate from all other ventilation. Arrangements of equivalent safety will be given special consideration.

111. Short circuit current calculations and coordination study

1. The protection and coordination of power systems are to be in accordance with Pt 6, Ch 1 of Rules for the Classification of Steel Ships, Ch 6 of Rules for the Classification of the Mobile Offshore Drilling Units, IEC, IEEE 242, or other recognized standards.

2. The maximum calculated short circuit current available at the main bus bars and at each point in the distribution system, is to be used to determine the adequacy of the short circuit capacities of the protective devices and bus bar bracing.

3. The power system coordination study is to show that the protective devices and their settings are properly selected to minimize damage to switchgear, transformers, generators, motors, conductors, conductor shielding and other equipment, as well as undesirable shutdowns.

112. Protection from Ignition by Static Charges

1. Any ignition hazard due to a difference in electrical potential to ground is to be effectively controlled. This may require the use of conductive belts, grounding of combustible fluid loading or discharge equipment and hose, and the grounding of helicopters prior to refueling.

2. All precautions against ignition due to static electric discharge are to be in accordance with NFPA 77, or other recognized standards.