Investigation Activity Report: CHARLESTON; Loss of Electrical Power
MISLE Activity Number: 2857418
Originating Unit: Marine Safety Unit Port Arthur
MISLE Activity Owner: Commandant (CG-5453)
MISLE Activity Controller: Commandant (CG-5453)
MISLE Case Number:
The M/V CHARLESTON had a loss of power due to an error in judgment by the Chief Engineer (CE),
while trouble shooting the number 3 Ships Service Diesel Generator (SSDG).
The vessel has 3 SSDGs. The STBD and CENTER units were online.
The CE was investigating the PORT generator auto circuit,
preparing to change out a suspected faulty standby generator selector switch.
In identifying the start circuit for the PORT SSDG,
the under voltage relay was bypassed and the start sequence timer power source was removed
to initiate the starting sequence of the PORT unit.
The engine started and the PORT generator came up to line voltage.
The under voltage relay normally open contacts completed the tripping circuits
of the STBD and CENTER units which were online at the time.
The CE incorrectly read the electrical schematics
interpreting bypassing of the under voltage relay to be sufficient
in disrupting the transfer sequence while enabling the starting sequence.
The ship lost power momentarily as the auto transfer sequence took place.
Under voltage protected equipment came back
online automatically as designed and the steering gear repowered.
The power source was replaced and the bypass were removed.
On 12JAN07 ABS conducted a Port State Control Survey.
The PORT, STBD, and CENTER SSDG were tested
by paralleling all 3 simultaneously and monitoring the load sharing capabilities.
The Reverse power trips were tested on each of the generators, and showed no adverse affects.