Section 4 Electrical, including container plug-in sockets

4.1.1 In addition to the requirements of Pt 6, Ch 2 Electrical Engineering, the following are to be complied with:

1. Electrical power for the ventilation system is to be provided by one or more separate feeder circuit(s) from the main switchboard.

2. Under sea-going conditions, the number and rating of service generators are to be sufficient to supply all container plug-in socket outlets and the hold space ventilation system in addition to the ship's essential services, when any one generating set is out of action.

4.1.2 The choice between a low (440 V) or high (6,600 V) distribution system serving the container plug-in point is considered a purely commercial decision. Consideration needs to be given to the fault level of the generating equipment selected and the total generating capacity of the ship. Independent of the system voltage, only the dedicated plug-in socket outlet kW value will be stated in the notation.

4.1.3 Where a distribution system exceeding 1000 V a.c. is employed, the plug-in socket outlets for each hold space may be fed from a local transformer and the following are to be complied with:

1. Transformers are to be fed from individual circuits divided between different sections of the main switchboard.

2. The electrical power for the ventilation system may be fed locally from each transformer.

4.1.4 Container plug-in socket outlets are to comply with the requirements of Pt 6, Ch 2, 13.6 Socket outlets and plugs.

4.2.1 A standby transformer serving the container plug-in socket outlets is to be provided. However, if the CRC notation is not assigned, then there is no specific requirement covering the installation of a standby power supply.

4.2.2 If a standby transformer is to be provided, then the exact requirements are open to interpretation and consideration should be given to the contents of IACS Unified Interpretation SC 83 with regard to the equipment provided.

4.3.1 The distribution and sub-circuit cabling for the container plug-in socket outlets is to be rated at the full load capacity (maximum rated capacity).

4.3.2 Groups of container plug-in socket outlets may be fed from a number of independent sub circuits.

4.3.3 Sub circuits are to be able to be individually switched, thus allowing a sequential start up after a prolonged (12 hours) blackout. A suitable procedure is to be proposed and approved that takes into consideration the requirements of Pt 7, Ch 10, 4.4 Generated power for plug-in socket outlets in addition to the requirements of Pt 6, Ch 2 Electrical Engineering.

4.4.1 When determining the dedicated generating power for the plug-in socket outlets, the electrical power drawn by the refrigeration unit of a standard TEU and FEU refrigerated container when working at both low temperature (minus 18°C) and chill temperature (2°C), is to be stated.

4.4.2 The following values for various cargoes operating at normal design conditions may be used for guidance purposes:

4.4.3 Twenty foot equivalent unit (TEU):

4.4.4 Forty foot equivalent unit (FEU) including high-cube containers:

4.4.5 If the Owner, charterer or operator has operational data indicating that, for the ship's specific trade (for example banana only cargoes), the power provision for the refrigerated containers requirements exceeds those stated above, then these higher values should be substituted and submitted for consideration.

4.4.6 The above values are for the container during normal operation after the cooling-down period of a non-precooled cargo.

4.4.7 An overall diversity factor may be applied to the container's total power requirement. Consideration is to be given to Pt 6, Ch 2, 5.6 Diversity factor. This diversity factor is to be applied to all refrigerated container cell locations. For guidance purposes, the diversity factor is not generally to be less than 0,75.