High Voltage safety procedure on Ship Electrical System
This is only a proposal how the procedure could look like, procedure must be established by the owner.
It is extremely important of following correct procedures while working with high voltage. An error would most probably be fatal working on a high voltage switchboard.
Like all work with high voltage, two persons are always required, with at least one electrician with a high voltage training course.
High Voltage Working procedure on Ship Bow Thruster
Pull the contactor out in test position by turning the interlock handle with left hand and pulling the operating handle as shown on figure 1. below.
Important! Open the door to make the earthing mechanism to be engaged. No need to unscrew the screws on the front panel.
Do this on all three contactors. Main C, By-Pass B and Star A.
Take out the ground interlock key on all three breakers.
The electrician should keep these keys personally until work is finished.
Open the connection box on the thruster.
Remember that high voltage equipment should be considered live until you have established visible earthing of the work place.
Do a voltage test with proper high voltage tester.
Remember to do a function test of the tester both before and after the actual test.
The work place is now ready to be earthed.
Connect all three phases to ground with proper high voltage earthing equipment designed for the short circuit currents.
The work place is now safe and ready for the needed maintenance.
Tool check list should be made, listing all tools that are being used.
This needs to be checked out when finished the work, making sure that no tools are left behind at the work place.
After finishing the work, disconnect the earthing apparatus again remember that the connections should now be considered “alive” since they are no longer grounded.
Return the keys and push all three breakers back in place.
It’s a good habit to stay away from the switchboard room first time connecting the breakers again in an unlikely case of forgotten tools etc, making a short circuit.
Please remember that this document is only a draft and needs to be reviewed and checked for errors.
