Page 207 - Offshore Electrical Engineering Manual

194 CHAPTER 1 Notes on Design Project Organization and Documentation

7. Panel wiring diagram
Again, these are normally produced by the equipment manufacturer, but may
require supplementing in certain instances. Modifications may be required
long after the manufacturer’s original involvement and it may not be possible
to call upon his assistance again.
8. Termination and interconnection diagrams
Having produced schematic and wiring diagrams, termination diagrams need
to be produced. These diagrams are the key to platform cable routing because
they not only highlight all equipment terminations but also identify all cables
and their cores. Once the majority of these have been identified, cable and rack
drawings can be produced in detail. Examples are given in Fig. 3.1.7.
9. Circuit breaker and starter schematic/wiring Diagrams
These are similar to other schematic and wiring diagrams, although the design
contractor will normally have a greater input to these because they will interface
with design information from a number of equipment manufacturers. One manu-
facturer may be responsible for the main switchboard and generators, in which
case there will be less for the design contractor to do. However, this still leaves
the design of interfaces between the main switchboard and the controls for all
the large process drives, such as main oil line pumps and gas compressors. These
diagrams must include the interfaces not only for the drive controls and instru-
mentation but also for platform monitoring systems such as emergency shutdown
and fire and gas systems. Examples of these drawings are shown in Fig. 3.1.8.
10. Hook-up diagram
With offshore labour cost approximately five times higher than that of onshore,
any means of presenting design information which will assist the offshore
electrical personnel in their task is worth considering. The hook-up diagram
is the electrician’s equivalent of a motorist’s route planning map. It follows an
individual circuit for a pressure switch, for example, through all the cabling,
back to the control panel and the source of electrical power, identifying every
terminal and cable core on the way, just as the motorist’s map would concentrate
on a description of the route between the departure and destination points. These
drawings tend to be used mainly for instrumentation, and each instrument con-
nection would be drawn on a separate sheet. An example is shown in Fig. 3.1.9.
11. Junction box and distribution board interconnection diagram
Every offshore installation has a multitude of junction boxes, terminal boxes
and distribution boards, and the interconnection of these must be detailed
adequately for both installation use and maintenance records. These drawings
will be similar to the interconnection diagram in Fig. 3.1.7.

DATABASES AND SCHEDULES
1. Cable schedules: A large offshore installation may have hundreds of kilome-
tres of cables installed and it is important that during the design stage as much
information on the identity, route size and type of each cable is retained. This