440V electrical shock incident

A member has reported an incident which a technician received a 440V electric shock. The incident occurred during an investigation of a power distribution unit (PDU) located in the ROV control room onboard a vessel. The purpose of the investigation into the PDU unit was to conclude whether the observation ROV being powered from this PDU was able to provide output data of a certain quality. The person who was shocked was not harmed and did not require any medical follow up.

Our member’s investigation revealed the following:

• The task was not a planned operation and it was performed by personnel with inadequate training/knowledge of the dangers associated with this work;
• The PDU was not properly labelled with warning signs, and had no top cover;
• There were two separate power supplies to the PDU; this was not identified due to the low level of familiarisation of involved personnel;
• The ROV supervisor was not notified about the operation;
• There was no job-specific permit to work (PTW) or any management of change. However, a generic PTW was made;
• There was a risk assessment but it was neither suitable nor sufficient – not according to requirements in regards to details, attendees and quality.

Our member noted the causes:

• The direct cause of the incident was that the technician touched or came near equipment that was powered to 440 V;
• The root causes identified were as follows:
  • Rescheduling of work tasks caused personnel to carry out ad-hoc investigations inside the PDU unit – There was poor safety awareness related to ongoing work – The PDU was inadequately labelled as being a place where there was danger of electrical shock
  • There was no detailed PTW completed – There was inadequate risk assessment underpinning the work on the PDU unit. The risk assessment was not performed to such a level of detail that it allowed actual risks to be disclosed
  • The persons doing the work were inadequately trained on this particular ROV system
  • There was inadequate quality and safety verification of equipment received onboard
  • It was not clear to personnel how the organization works offshore.

The following lessons were identified:

• Stop the job if you feel unsafe;
• Follow the requirements as defined in management system;
• Always inform supervisor;
• Always complete familiarisation;
• Always make a detailed risk assessment and be compliant with the control of work system;
• There should be thorough verification and site acceptance of new equipment, particularly with regard to quality, labelling, design and location on board.

Our member took steps to:

• Revise bridging document with focus on clear communication lines;
• Ensure control of work system was understood by all crew on board;
• Revise risk assessment, training matrix and amended procedures to avoid repetition.

Members may wish to refer to the following similar incidents (key words: electric, shock):

• Risk of electrocution during routine work
• Fatal electrocution
• Crewman received 440V electric shock
• Recent near-miss incidents involving potential dropped objects