Page 211 - The ROV Manual - A User Guide for Remotely Operated Vehicles 2nd edition

200 CHAPTER 8 Cables and Connectors
A designer should investigate all potential cable design solutions, including:
• Cable designs for similar applications
• Modify a similar application cable construction
• Modify a COTS cable
• Design a unique EOM cable specifically for the application
• Review the cable design solution to ensure it satisfies the requirements
• Manufacture a prototype and/or production cable design
As noted above, a custom cable design can provide variations in:
• conductor materials and strand numbers,
• insulation materials,
• jacket/sheath materials and construction, and
• the strength member.
8.8.7 Conductors
Conductors are the heart of the electrical cable (Figure 8.43). The most common wires are as
follows:
• Copper
 Tin-plated copper provides the best soldering and availability and is the most common
material used in ROV cables.
 Bare copper provides for lowest DC resistance at the termination, but surface oxidation
creates problems with soldering, while availability is poorer.
 Silver-plated copper is the best choice for higher temperature and signal frequency but
comes at a higher cost and longer lead time.
• Stranding (Figure 8.44)
 Use solid wire for non-flexing applications only.
 Higher number of strands provides greater flexing.
8.8.8 Insulation
As noted above, there are two families of insulation materials: thermoplastics and thermoset plas- tics. Materials vary on cost, operating temperature range, insulation value, and bonding ability (Figures 8.45 and 8.46).
8.8.9 Jacket/sheath
The sheath is the inner core wrapping that binds the cable assembly together prior to extruding the
outer jacket. Materials widely used include:
 Polyolefin (PE and PP)
 Polyurethane
 Thermoplastic elastomer (TPE)