2 – Installation
DPN 402197 Issue 7.1
© Teledyne Limited
2- 13
2.3.1 Ground Connections
If you provide the 350 system with an inadequate ground connection parts of the system will act as
‘sacrificial anodes’ and will slowly decay during subsea operations. This will occur whether or not you
use the 350 system.
To prevent corrosion affecting the system in this way, you must connect pin 2 of the 8-way SEP ‘Power/
Comms’ port locally to the ROV using a ground connection at sea water potential.
IMPORTANT
To ground the SEP use only a local grounding point on the ROV frame. Do not use
a core within the umbilical to ground the 350 system because there will inevitably
be a potential difference between the ROV and the surface vessel.
These grounding provisions hold the 350 system at the same electrical potential as the sea water. This
prevents the occurrence of electrochemical action between the system and the sea water and
minimises galvanic corrosion.
2.3.2 Care of Subsea Connectors
Before you assemble any electrical coupling in the subsea installation, inspect the pins and
receptacles of all connectors for signs of damage, contamination or corrosion. To ensure reliable
operation and to extend the life of the subsea installation, take the following precautions to care for the
sub-sea connectors used throughout the 350 system:
1. Keep both the connector and socket free from debris and salt build up.
2. Use warm soapy water to wash the connectors, and then rinse them with clean fresh water. Do
not use any solvents on the connectors. Allow the connectors to dry thoroughly in air before
you reassemble them.
3. Lubricate the mating face of the connectors with a very light spray of
3M Silicone Oil
or
Dow
Corning #111
valve lubricant or equivalent.
Do not use grease.
CAUTION
Some silicone lubricants will crystallise when you subject them to sea water under
pressure. When this happens, the seals of the connector will degrade and allow
water to penetrate.
To avoid damage to the connectors, use only the lubricant oils mentioned above,
or equivalent oils that the manufacturer approves specifically for use on deep-sea
connectors and seals. When you apply the lubricant oil, use a very thin coating
only.