2006 Muttrah Incident Report - authority for electricity regulation, oman

into the service position) were rated at 800 Amps and not 400 Amps as specified in
the contract. ABB decided to remove the 400 Amp contacts from the old Brush OCB
trucks and use them to replace the 800 Amp contacts on the new VCB trucks. In
order to do this it was necessary to machine a total of 100 copper terminals and ABB
staff proceeded to Wadi Khabeer Industrial Area in order to have this machining
carried out. The use of the tulip contacts from the original Brush trucks and the
machining of the copper terminals was not discussed with MEDC and therefore was
done without approval.
• MEDC engineers left site at approximately 1500 hrs.
• Subsequently ABB advised that they proceeded to rack in and rack out new VCB
trucks on 3 Feeders: Darsait, Oman House, and Gharifa. The VCB truck on the
Darsait feeder was left racked in and in the service position.
• ABB also advise that the VCB truck associated with the Al Harthy feeder was then
racked in to the service position with the cubicle door open. The VCB itself was in the
open position with its protection inoperative. ABB were preparing to leave site and
were tidying up their tools when at 1846 hrs a flashover occurred inside the Al Harthy
feeder cubicle.
• Two ABB employees were directly in front of the cubicle and received the full force of
the flashover, which ignited their clothing. They ran out of the substation and the
ABB supervisor assisted by members of the public extinguished the fire on their
clothing.
• The ABB supervisor called the emergency services but there was a delay of some 45
minutes before the arrival of the ambulance. During this period it is understood that
the injured persons were not given any first aid. Following arrival of the ambulance
the injured persons were taken to Khoula Hospital where they subsequently
succumbed to their injuries.
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