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#22629 - 02/26/03 03:28 AM Ever asked to work on something your not familiar with ?
Arthur Phares Offline
Junior Member
Registered: 02/20/03
Posts: 3
Loc: Shelbyville, IN U.S.
Do you suppose this guy was told to work on 7000v, or volunteered? Take notice to how knowone knows why he was doing what he was.

At 2:00 a.m., the Letcher Fire and Rescue Ambulance Service arrived at the scene and transported the victim to the Whitesburg Appalachian Regional Hospital located at Whitesburg, Kentucky. Robert A. Campbell, Letcher County Coroner, examined the victim and pronounced Paul Dean Campbell dead at 3:30 a.m.

The investigation revealed the following factors relevant to the occurrence of the accident:

The mine receives power through a 34,500 VAC service drop. Power is transformed at that point to 7,200 volts by three 1,250 KVA transformers at an open-type surface substation for underground transmission.

Two overcurrent relays and one ground fault relay were installed at the surface substation. These relays provide the required protection to the high voltage circuit underground (for the 006 and 007 working sections). The Phase "A" overcurrent relay tripped due to an overcurrent condition (settings and testing indicated the trip value to be 240 amperes). The Phase "C" relay had tripped due to both an instantaneous current trip condition (settings and calculation indicate the trip value at 1,200 amperes) and an overcurrent condition (settings and testing indicated the trip value was 230 amperes). The ground fault relay had tripped due to an overcurrent condition (the ground fault relay was set to trip at 5.2 amperes). It could not be determined when these relays had activated.


Overcurrent Trip
(Actual)Phase A 240 amperes, Phase C 230 amperes, Ground 5.2 amperes
Overcurrent Trip
(Calculated), Phase A 240 amperes,Phase C 240 amperes, GRound 5.0 amperes.
(Calculated) Phase A 1,600 amperes, Phase C 1,200 amperes, Ground 40 amperes.
Time Setting** Pase A 8.5 (numeric value),Pase C 6.0 (numeric value), Ground 0.5 (numeric value).

** The numeric value for the time setting on the three relays must reference a chart to determine the time needed to trip the relay.

Two overcurrent relays and one ground relay were also present in the 007 section loadbreak switch located approximately 1,500 feet underground. The loadbreak switch is not recognized as the legal protective device for the No.2 AWG high voltage cable to the 007 section. Section 75.800, 30 CFR, recognizes only circuit breakers for the purposes of undervoltage, grounded phase, short circuit, and overcurrent protection. The phase "A" relay in the loadbreak center was activated due to an instantaneous overcurrent condition. The phase "C" relay was activated due to an instantaneous overcurrent condition. The ground fault relay was activated due to a timed overcurrent condition.
The high-voltage circuit that supplied 7,200 VAC three phase power to the 007 section was not deenergized, grounded, locked out, or suitably tagged before the power move and electrical work was performed. No one was instructed to lock or tag the 7,200 VAC high-voltage circuit to the 007 section before the power move.
Monthly examinations of high-voltage electrical equipment had not been conducted since October 5, 1997.
The operator was not maintaining a list of certified or qualified persons to perform electrical duties at this mine.
The 7,200 VAC high-voltage loadbreak switch for the 007 working section was not operating properly. The mechanical assembly of the switch would not work when tested.
The high-voltage load break switch supplying power to the 007 working section was not identified as the controlling switch for the circuit.
The 1,250 KVA 007 section power center was moved while energized.
The high-voltage 7,200 VAC visible disconnect on the section power center had been placed in the open position prior to the power move. The section power center was still energized during and after the move. The power center was moved one crosscut. The 7,200 VAC visible disconnect had not been closed immediately after the power center move stopped. Closure of the disconnect would have given an audible tone (through a humming sound) created by the energized transformers indicating to the victim that the 7,200 VAC circuit was energized.
The allen bolts on the female receptacle that supplied 995 VAC three phase power to the continuous miner had been unbolted from the power center frame.
A replacement female receptacle for the 995 VAC circuit was found laying beside the unbolted receptacle.
Allen wrenches were found in the victim's possessions following the accident.
The cover for the 7,200 VAC splice box was found laying at an angle on the side of the splice box.
The high-voltage failsafe ground monitor circuit contained a short circuit on the outby side of the high-voltage splice box where the victim was working. This condition prevented the sectionalizer loadbreak switch from tripping when the cover on the splice box was removed. The splice box had two high voltage ground monitor cover switches installed, one of which was found to be locked in the closed contact position. The other cover switch was operative.
A 9/16" combination wrench (open-end/boxed-end) was found inside the splice box. Five bolts within the splice box were 9/16" in size. The three phase-lead termination bolts were 9/16" and the two termination point bolts for the high voltage monitor wire were 9/16".
Electrical arc marks were found on all three 7,200 VAC phase conductor stand-off insulators located within the splice box. Apparently, the victim believed there was a ground monitor problem or a loose connection on one of the three 7,200 VAC phase conductor stand-off insulators.
Miners who were near the section power center at the time of the accident stated they heard a loud pop and/or saw flashes.
The victim was found lying face down on top of the splice box.
Evidence indicates that the victim made contact with at least two phases of the 7,200 VAC circuit inside the splice box and that this contact initiated an arc which resulted in burn injuries to the victims left arm.
Testimony of coworkers and management personnel indicated that no one had any knowledge as the reason(s) for the victim performing work inside the splice box. The lug nuts on the phase terminals and the ground monitor terminal inside the splice box were 9/16-inch in size. A 9/16-inch combination wrench was found inside the splice box. The investigation team's consensus is that the victim apparently intended to work on either the ground monitor wire terminal or one of the 7,200-volt phase terminals.

The victim was not a certified electrician.

There was no certified electrician (as defined by 30 CFR, Part 75.153) on the 007 working section at the time of the accident.

A volt/ohm meter was not found near the accident scene.

The certificate of death lists the immediate cause of death as electrocution.

[This message has been edited by Arthur Phares (edited 02-26-2003).]

[This message has been edited by Arthur Phares (edited 02-26-2003).]
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