Transcript Electrical Hazards - Mine Rescue Association

Electrical Hazards
• Electrical accidents in the mining industry
are caused by:
1. Failure to lockout/tag electrical equipment
2. Unqualified people doing electrical work
3. Contact with overhead powerlines
4. Improper installation and maintenance
Consequences of electrical
accidents
• Fires and Explosions
• Burns
• Shock/Electrocution
Fires and Explosion
We can prevent fires and explosions by:
• Preventing overcurrent conditions such as short
circuit or overload and using proper protection
for circuits and equipment;
* using installation methods to protect conductors
and equipment from damage or contact that
might result in an arc or overcurrent condition or
shock; and
* using equipment designed to prevent arcing
during normal operation which could cause an
explosion.
Burns
• Electrical arcs produce tremendous amounts of
heat. We can attest to this from the use of
electrical arcs for welding metals. The
temperature of an electric arc at currents of 2-20
Amps can range from 3600 to 7200 degrees at
the starting and ending points of the arc.
• The heat from normal arcing causes some
destruction of equipment components such as
contacts, commutators, etc. Periodic
maintenance is necessary to take care of these
losses.
Shocks and Electrocutions
• There are several factors that can be
detrimental during electrical shock. These
factors include, but are not limited to:
Amount of current
Time exposed
and, Current path through the body
Let’s look at Ohm’s Law
EFFECTS OF
CURRENT ON THE
AVERAGE BODY
How much current does it
take to illuminate this 60
watt, 120 volt light bulb?
• The answer is 0.5 amperes
or 500 milliamps.
60 WATT
• Did you know that this is
five times the current that
it takes to fatally
electrocute someone ?
120 VOLTS
CURRENT
EFFECT
1 MILLIAMP
THRESHOLD OF
PERCEPTION
1 TO 8 MILLIAMPS
SENSATION
OF SHOCK
8 TO 15 MILLIAMPS
PAINFUL SHOCK
15 TO 20 MILLIAMPS
LOSS OF MUSCLE
CONTROL
20 TO 50 MILLIAMPS
BREATHING IS
DIFFICULT
100 TO 200 MILLIAMPS
VENTRICULAR
FIBRILLATION
OVER 200 MILLIAMPS
SEVERE BURNS
GFCI
sound
On August 17, 2002, a 31-year-old contract miner with 4 years
of experience was fatally injured in a tunnel construction
project at an open pit copper mine. A transformer switch,
mounted on a rail car, was being moved forward as construction
advanced. The victim was electrocuted when he contacted a 480
volt cable and a junction box to move them from rubbing the
rail car. The cable and junction box were part of the lighting
system located along the side of the tunnel.
report
CONCLUSION
The cause of the accident was the failure to provide an
effective low impedance grounding circuit for the
tunnel lighting system.
The following root causes were identified: failure to
properly assemble the light fixture; failure to properly
test the light fixture and failure to properly test the
resistance of the light circuit ground system.
Citation No. 6273824 was issued on August 18, 2002, under the
provisions of Section 104(d)(1) of the Mine Act for violation of
30 CFR 57.12001:
On August 17, 2002, a fatal accident occurred at this
mine when a contract miner contacted an energized
480/277 volt cable attached to a metal light assembly.
The tunnel lighting system/circuit was not protected
against excessive overload with fuses or circuit breakers
of the correct types and capacity. Failure to ensure that
the circuit overload protection was properly installed
and maintained constitutes more than ordinary
negligence and is an unwarrantable failure to comply
with a mandatory standard.
Order No. 6273825 was issued on August 18, 2002, under the
provisions of Section 104(d)(1) of the Mine Act for violation of 30
CFR 57.12025:
On August 17, 2002, a fatal accident occurred at this mine
when a contract miner contacted an energized 480/277 volt
lighting circuit attached to a metal light assembly. The
metal frame of the light assembly was energized in excess of
150 volts, phase-to-ground. The metal enclosing and
incasing electrical circuit was not effectively grounded or
provided with effective equivalent protection. Excessive
impedance of the primary and secondary equipment
grounding circuit did not provide for sufficient current flow
to open the provided protection. Failure to ensure that
effective grounding was provided for the circuit, constitutes
more than ordinary negligence and is an unwarrantable
failure to comply with a mandatory standard.
report
On October 2, 2001, a contract electrician was fatally injured at a
sandstone operation. The victim had been installing power lines to
an elevated electrical box mounted on the side of a building. As he
swung the manlift he was working from away from the building he
contacted high voltage power lines that were located above his
work area.
104(a) Citation for violation of 56.12071:
A fatal accident occurred at this operation on October 2, 2001,
when a contract electrician in a JLG manlift basket, contacted
energized overhead high voltage power lines. The manlift being
used had the reach capacity to contact overhead power lines yet
the lines were not de-energized nor were other precautionary
measures taken to protect persons.
30 CFR § 56.12071
Movement or operation of equipment near high-voltage power
lines.
When equipment must be moved or operated near energized highvoltage powerlines (other than trolley lines) and the clearance is less
than 10 feet, the lines shall be deenergized or other precautionary
measures shall be taken.
On September 16, 2002, a 42 year-old welder
with 2 years mining experience was fatally
injured at a crushed stone operation. The
victim was lying on a wet, metal screen deck
welding a wear plate in a confined area
when he apparently touched the energized
welding rod to his chest and received an
electrical shock.
report
The cause of the accident was the victim contacting
the energized welding electrode. The root causes
were the failure to utilize dry insulating material
while welding when lying on steel, and failure to
wear dry clothing.
No citations issued
On Tuesday, March 13, 2001, an electrical
contractor, with 16 years of experience, was
fatally injured when he contacted high voltage
power while installing pole mounted capacitors.
The victim and two co-workers had completed
the installation of the capacitors, located
approximately 900 feet from the mine substation,
and installed a size 14 twisted pair wire from the
substation to the capacitors to provide 120 volt
control power for a capacitor switching device.
The victim, two co-workers and three mine
employees, were standing at the mine substation
when the plug for the twisted pair wire began to
smoke and arc.
The victim, pulled the plug from the receptacle, picked
up the plug to examine it and received a fatal electrical
shock. A phase imbalance was caused when a defective
switch on one of the capacitors failed to close and
induced a current flow onto the frame of the capacitors
and the ground wire extending down the pole to a
ground rod. The frames were common with the neutral
wire of the size 14 control power conductor. When the
victim contacted the neutral wire, he became a parallel
path for this current flow.
report
A 104(a) Citation was issued to the operator for a violation of 77.502.
The citation stated, "It was determined that electric equipment involved
in the accident was not properly examined, tested and maintained by a
qualified person to assure safe operating conditions. The following
dangerous conditions were found to exist: (1) One of the three oil
switches used to control the capacitors was not working properly. The
electrical contact tips were worn and not making proper contact. Bolts
that held the switching mechanism in place were missing or loose. The
oil inside the switch was contaminated. (2) The capacitors were not
installed according to manufacturers recommendations. (3) The
resistance of the capacitor frame ground was too high to provide a proper
low resistance grounding medium. (4) A 14/2 TW twisted pair telephone
wire, without ground conductor, was used to supply 120 volt control
power. (5) Control power for capacitor bank location, this would reduce
transfer of voltage potentials. This condition contributed to the accident
that occurred on March 13, 2001.
A 104(a) Citation was issued to the contractor for a violation of 77.502. The citation
stated, "It was determined that electric equipment involved in the accident was not
properly examined, tested and maintained by a qualified person to assure safe operating
conditions. The following dangerous conditions were found to exist: (1) One of the
three oil switches used to control the capacitors was not working properly. The
electrical contact tips were worn and not making proper contact. Bolts that held the
switching mechanism in place were missing or loose. The oil inside the switch was
contaminated. (2) The capacitors were not installed according to manufacturers
recommendations. (3) The resistance of the capacitor frame ground was too high to
provide a proper low resistance grounding medium. (4) A 14/2 TW twisted pair
telephone wire, without ground conductor, was used to supply 120 volt control power.
(5) Control power for capacitor switching was not derived at the capacitor bank
location, this would reduce transfer of voltage potentials. This condition contributed to
the accident that occurred on March 13, 2001."
30 CFR § 77.502
Electric equipment shall be frequently examined, tested, and properly
maintained by a qualified person to assure safe operating conditions.
When a potentially dangerous condition is found on electric equipment,
such equipment shall be removed from service until such condition is
corrected. A record of such examinations shall be kept.
POLICY
77.502 Electric Equipment; Examination, Testing and Maintenance
For purposes of this Section, "electric equipment" shall include all
control circuits; control switches or devices; circuit breakers; fuses;
conduits; wiring; motors; transformers; lighting equipment; hand-held
tools such as drills, wrenches, and saws;etc. The tests, examinations, and
proper maintenance required by this Section shall include all items
mentioned above and all other such equipment at the mine.
A 104(a) Citation was issued to the operator for a violation of 77.501.
The citation stated, "It was determined that electrical work was
performed by persons who were not qualified or were not under the
direct supervision of a qualified person as provided by 77.103. The
following electrical work was performed: (1) A 120 volt control circuit
was installed with wiring connection made inside a junction box and
plug end installed. (2) Splices were made in the 120 volt control wire. (3)
Installation of capacitors and connection to the 12,470 volt power
conductors. (4) Lock and tag out. (5) Installation of grounding
conductors. This condition contributed to the accident that occurred on
March 13, 2001.
A 104(a) Citation was issued to the contractor for a violation of 77.501.
The citation stated, "It was determined that electrical work was
performed by persons who were not qualified or were not under the
direct supervision of a qualified person as provided by 77.103. The
following electrical work was performed: (1) A 120 volt control circuit
was installed with wiring connection made inside a junction box and
plug end installed. (2) Splices were made in the 120 volt control wire. (3)
Installation of capacitors and connection to the 12,470 volt power
conductors. (4) Lock and tag out. (5) Installation of grounding
conductors. This condition contributed to the accident that occurred on
March 13, 2001."
30 CFR § 77.501
No electrical work shall be performed on electric distribution circuits
or equipment, except by a qualified person or by a person trained to
perform electrical work and to maintain electrical equipment under the
direct supervision of a qualified person. Disconnecting devices shall be
locked out and suitably tagged by the persons who perform such work,
except that in cases where locking out is not possible, such devices
shall be opened and suitably tagged by such persons. Locks or tags
shall be removed only by the persons who installed them or, if such
persons are unavailable, by persons authorized by the operator or his
agent.
POLICY
"Electrical work," as referred to in this Section, includes the design, installation, maintenance or
repair of electric equipment and circuits. Splices and terminations made in electric cables,
installation of couplers on the ends of cables, electric machine repairs, electric wiring, pole and
line work, work performed inside electrical substations or other areas in proximity to exposed
energized electrical parts, work performed inside transformers, switchboxes, switch houses,
electric panels or other enclosures of electric equipment and circuits are examples of tasks that
are considered to be "electrical work" and are required to be performed by or under the direct
supervision of a qualified person.
POLICY 77.501
Examples of duties that are not considered to be "electrical work" and would not be required to
be performed by a qualified person or under the direct supervision of a qualified person are,
operation of electric equipment, transportation of equipment and cables, operation of control
switches, circuit breakers or switchboxes, provided no energized parts are exposed, changing
cutting bits, lubrication work, moving of energized trailing cables, or inserting or withdrawing
proper cable couplers into or from their receptacles. These tasks are considered to be part of
the normal routine operation of electric equipment; therefore, they are not considered to be
"electrical work."
The term "direct supervision" shall not be interpreted to mean that the qualified person be
physically present at all times during the performance of such repairs, but the qualified person
has the following responsibilities:
1.The qualified person shall examine and/or test an electric circuit or machine
and determine the need for repair or maintenance.
2.The qualified person must give specific instructions to the employee assigned
to perform this work with respect to the nature and extent of the repairs to be
performed and, where necessary, prescribe the manner in which the work is to
be performed.
3.The qualified person is, at all times, under continuing duty to instruct, advise,
or consult with the employee, in the event the work assigned cannot be
performed by the employee in the manner prescribed.
POLICY 77.501
4.The qualified person must examine and test the completed work before
the circuit is energized or the machine is returned to service.
It is MSHA's policy that a person trained to perform electrical work and to maintain
electric equipment under the direct supervision of a qualified person shall not be
assigned the duty of testing or troubleshooting energized circuits. Persons trained to
perform electrical work and to maintain electric equipment may only do testing and
troubleshooting on energized circuits as part of their training program. During this
testing and troubleshooting operation, a qualified person, as defined in Section 77.103,
must be present at all times to observe,instruct, and aid the trainee.
"Suitably tagged" means that a sign with wording such as"Danger - Hands Off - Do Not
Close - Miners Working on Line,"shall be attached to the opened disconnecting device.
The tag should bear the name of the workman who installed it.
Keys to locks used to lock out switches should be kept by the person working on the
circuit or equipment
A 104(a) Citation was issued to the operator for a violation of 77.516. The citation
stated, "It was determined that improper wiring methods were used to supply the 120
volt control power for the capacitor switching circuit. A 14/2 TW twisted pair telephone
wire, without ground conductor, was used. A 120 volt three-prong plug was installed on
the 14/2 wire and plugged into a ground fault circuit interrupter outlet at the mine
substation. The 14/2 wire ran for 733 feet along the highwall, lying on the ground, and
suspended on trees at some locations to the pole mounted capacitors. Splices were made
in the 14/2 wire. The capacitor manufacturer recommends control power be derived at
the capacitor bank location. Reference the following articles of the 1968 National
Electrical Code: 250-59 which requires a grounding conductor to be run with the power
supply conductors; 300-4 which provides for protection against damage; 310-1(a)
which requires that conductors have mechanical strength, insulation, and ampacity
adequate for the conditions; 400-4 which prohibits use of cords for this application; and
400-5 which requires cords to be used in continuous lengths without splices. This
condition contributed to the accident that occurred on March 13, 2001
A 104(a) Citation was issued to the contractor for a violation of 77.516. The citation
stated, "It was determined that improper wiring methods were used to supply the 120
volt control power for the capacitor switching circuit. A 14/2 TW twisted pair telephone
wire, without ground conductor, was used. A 120 volt three-prong plug was installed on
the 14/2 wire and plugged into a ground fault circuit interrupter outlet at the mine
substation. The 14/2 wire ran for 733 feet along the highwall, lying on the ground, and
suspended on trees at some locations to the pole mounted capacitors. Splices were made
in the 14/2 wire. The capacitor manufacturer recommends control power be derived at
the capacitor bank location. Reference the following articles of the 1968 National
Electrical Code: 250-59 which requires a grounding conductor to be run with the power
supply conductors; 300-4 which provides for protection against damage; 310-1(a)
which requires that conductors have mechanical strength, insulation, and ampacity
adequate for the conditions; 400-4 which prohibits use of cords for this application; and
400-5 which requires cords to be used in continuous lengths without splices. This
condition contributed to the accident that occurred on March 13, 2001."
30 CFR § 77.516
In addition to the requirements of §§77.503 and 77.506, all wiring and
electrical equipment installed after June 30, 1971, shall meet the
requirements of the National Electric Code in effect at the time of
installation.
POLICY
Section 77.516 requires, in addition to compliance with Sections77.503 and 77.506, that
electric equipment installed after June 30, 1971, meet the requirements of the NEC. The
NEC has been incorporated into MSHA standards to address wiring and wiring methods
for surface facilities and structures not specifically covered in Part 77. The NEC will
continue to be applied to surface facilities and structures other than the specified
excavation equipment. The NEC contains safety guidelines which are not specifically
tailored to surface mine excavation equipment and conductors, but which cover a much
broader scope. While Section 77.516 addresses wiring and electric equipment installed
after June 30, 1971, on surface mining machines, many provisions of the NEC are not
applicable to the wiring methods, types of equipment, and conditions on these
machines. For example, certain excavation equipment designed and installed since June
30, 1971, is not compatible with the requirements of the 1968 NEC. Therefore, strict
application of and compliance with the NEC for the wiring methods used on surface
mine excavation equipment is not practicable.
Wiring and electric equipment installed after June 30, 1971, on-board electric
or diesel-powered surface excavation equipment are not required to comply
with the NEC under Section 77.516,although mine operators are free to rely
on it as a guideline.This policy applies to equipment such as draglines,
shovels, dozers, bucket wheel excavators, mobile drills, mobile
cranes,haulage trucks, and endloaders. However, all other relevant provisions
in Part 77 will continue to apply to these machines.Equipment and wiring
installed after June 30, 1971, will be inspected and enforcement action taken
in the same manner as on equipment installed prior to that date. For example,
Sections77.404 and 77.502 requiring examination and proper maintenance
will be enforced, along with appropriate conductor ampacities under Section
77.503, short-circuit and overload protection under Section 77.506 and all
relevant grounding provisions.
A 104(a) Citation was issued to the operator for a violation of 77.701.
The citation stated, "It was determined that the metallic frame of the
capacitor bank was not properly grounded to a low- resistance ground
field. A copper rod was driven into the ground at the base of the pole
(butt ground) to create a ground/neutral point for the capacitor
installation. The value of the butt ground was measured and found to be
195 ohms. Regulation requires that the grounding conductor extend to a
low-resistance ground field. This condition contributed to the accident
that occurred on March 13, 2001
A 104(a) Citation was issued to the contractor for a violation of 77.701.
The citation stated, "It was determined that the metallic frame of the
capacitor bank was not properly grounded to a low- resistance ground
field. A copper rod was driven into the ground at the base of the pole
(butt ground) to create a ground/neutral point for the capacitor
installation. The value of the butt ground was measured and found to be
195 ohms. Regulation requires that the grounding conductor extend to a
low-resistance ground field. This condition contributed to the accident
that occurred on March 13, 2001."
30 CFR § 77.701
Metallic frames, casings, and other enclosures of electric equipment
that can become "alive" through failure of insulation or by contact with
energized parts shall be grounded by methods approved by an
authorized representative of the Secretary.
POLICY
Certain moveable electric equipment, e.g., rail-mounted and pivoting coal stackers,
traveling shop cranes on track rails, small traveling hoists on I beams, etc., cannot be
strictly classified as portable, mobile or stationary equipment. For the purposes of frame
grounding, such equipment shall be considered stationary. Consequently, the grounding
requirements of Subpart H apply to such equipment.
This Section requires that metallic frames of electric equipment be grounded by
methods approved by an authorized representative of the Secretary. Therefore, railmounted and pivoting coal stackers, traveling shop cranes on track rails, small traveling
hoists on I beams, and similar equipment shall be grounded in accordance with the
following:
A 104(a) Citation was issued to the operator for a violation of
77.1710(c). The citation stated, "It was determined that the victim was
not wearing protective gloves when he pulled the 120 volt control power
plug from the receptacle and then picked up the plug. The plug was
arcing and smoking. The victim received a fatal electrical shock as power
fed back on the control wire from the capacitor bank. This condition
contributed to the accident that occurred on March 13, 2001
A 104(a) Citation was issued to the contractor for a violation of
77.1710(c). The citation stated, "It was determined that the victim was
not wearing protective gloves when he pulled the 120 volt control power
plug from the receptacle and picked up the plug. The plug was arcing and
smoking. The victim received a fatal electrical shock as power fed back
on the control wire from the capacitor bank. This condition contributed
to the accident that occurred on March 13, 2001."
30 CFR § 77.1710
Each employee working in a surface coal mine or in the surface work
areas of an underground coal mine shall be required to wear protective
clothing and devices as indicated below:
(c) Protective gloves when handling materials or performing work
which might cause injury to the hands; however, gloves shall not be
worn where they would create a greater hazard by becoming entangled
in the moving parts of equipment.
POLICY
Paragraph (c) of this Section requires that miners wear gloves whenever they
troubleshoot or test energized electric power circuits or electric equipment. Work gloves
in good condition are acceptable for troubleshooting or testing energized low- and
medium-voltage circuits or equipment. High-voltage gloves, rated at least for the
voltage of the circuit, are required for troubleshooting or testing of energized highvoltage circuits or in compartments containing exposed energized high-voltage circuits.
On Friday, July 20, 2001, a 26 year old electrician, with 5 years mining experience, was
fatally injured in an electrical accident. The victim was preparing to move an
electrical starter box, which provided power to the No. 9 belt conveyor head drive.
Apparently, the victim came in contact with the energized electrical circuit providing
power to the starter box or other associated electrical equipment.
104(d)(1) Citation - Work was performed on electrical circuits and
equipment without all power first being deenergized, while under the
direct supervision of the chief electrician. The electrical circuit (277
volts) entering the # 9 belt starting box and supplying power to the 20 HP
booster pump was not deenergized prior to work being performed on the
energized circuit.
104(d)(1) Order - The 010 MMU section's 20 HP booster pump located
outby the # 9 belt drive was not grounded as required. A separate circuit
originating from the booster pump starter had been installed to the # 9
belt box. The start/stop switch had been defeated (by-passed). This
circuit permitted the pump to start when the # 9 belt started. Power was
supplied to the circuit by the 16/3 pump cable conductor. The ground
wire had been cut off at both ends where the cable left the pump starter
and where the cable entered the belt box. With the # 9 belt box
disconnect device unplugged, the # 9 belt box was still energized with
480 volts from the 20 HP booster pump and had no means of proper
grounding.
104(d)(1) Order- Mine management failed to insure that all electrical
circuits and equipment were properly locked out and suitably tagged
while electrical work was being performed. The electrical circuit serving
the 20 HP booster pump was not locked out and suitably tagged while
electrical work was being performed.
104(d)(1) Order- Electrical equipment (20 HP booster pump and the # 9
belt drive's starting box) had not been properly examined and maintained
to assure safe operating condition. An examination of this equipment
revealed the following conditions : 1) A separate circuit originating from
the booster pump's start box had been wired to the # 9 belt box; 2) The
start/stop switch located on the booster pump had been defeated (bypassed), allowing the booster pump to start when the # 9 conveyor belt
was started; 3) The ground wires were found to have been cut at the
booster pump and the belt drive starting box; and 4) The 20 HP booster
pump was not listed in the records of the examination of electrical
equipment.
30 CFR § 75.512
All electric equipment shall be frequently examined, tested, and properly maintained
by a qualified person to assure safe operating conditions. When a potentially
dangerous condition is found on electric equipment, such equipment shall be
removed from service until such condition is corrected. A record of such examinations
shall be kept and made available to an authorized representative of the Secretary and
to the miners in such mine.
104(a) Citation - The site of an accident that resulted in the death of a
mine electrician on July 20, 2001, was found to have been altered prior
to the completion of all investigations, and without MSHA approval. It
was determined that the site was altered due to the following: 1) The
disconnect device (cat-head) which supplied power to the 20 HP booster
pump had been disconnected at the 300 KVA power center and was lying
on the mine floor; 2) The 16/3 cable extending from the booster pump to
the # 9 belt drive starting box had been cut at the pump start box
location; and 3) The 16/3 cable extending from the booster pump to the #
9 belt drive starting box had been disconnected from the inter lock on the
vacuum breaker and had been pulled completely out of the belt box.
None of these conditions could have existed at the time of the fatal
accident. Mine management failed to preserve and secure the accident
site. PART 50 VIOLATION
104(d)(1) Order - The electrical circuit breaker supplying power to the
20 HP booster pump located outby the # 9 conveyor belt drive was not
properly marked for identification. The subject electrical circuit breaker
was identified and labeled as "pump", but was in fact supplying electrical
power for two different devices; the pump and a separate circuit entering
the # 9 belt starting box.
30 CFR § 75.904
Circuit breakers shall be marked for identification
POLICY
75.904 Identification of Circuit Breakers
Either metal or plastic tags or markers may be used to identify circuit
breakers if the tags or markers are attached securely to the circuit breaker
enclosure and are large enough to be readily seen. The tag or marker
should clearly identify the circuit or machine receiving power through
the circuit breaker.
On Thursday, January 24, 2002, a 43 year old general inside laborer was fatally injured
while performing electrical work on the 12,470 volt underground power center located
on the 001-0 section. During retreat mining a length of high voltage cable was removed.
Problems were encountered with re-energizing the power at the substation on the
surface after the cable was re-stocked in the section power center.
report
The certified electrician came outside to check on the problem. When power was
restored to the section it was discovered that the phasing was wrong. Power was
removed from the section to correct the phasing. The victim was working on the leads
inside the power center when the 001-0 section power was again re-energized from the
surface, resulting in a fatal electrical accident.
104(a) Citation No. 7293099 was issued March 6,
2002, for a violation of 30 Code of Federal
Regulations (CFR) 75.800: The high-voltage circuit
entering the underground area of this coal mine
did not have an effective device to provide
protection against under-voltage, grounded phase,
short circuit or overcurrent as tested on January
25, 2002.
104(d)(1) Order No. 7293100 was issued March 6, 2002,
for a violation of 30 CFR 75.705-1(b): The high-voltage
circuit supplying 12,470 VAC, three phase power to the
underground areas of the mine was not determined to
be properly deenergized by a qualified person before
electrical work was performed on it.The evening shift
foreman and electrician was the only qualified person
at the mine on January 24, 2002. He deenergized the
underground high-voltage visual disconnect but did not
ensure that each ungrounded conductor of the highvoltage circuit upon which work was to be done was
properly connected to the system-grounding medium.
104(d)(1) Order No. 7323521 was issued March 6, 2002, for a
violation of 30 CFR 75.511: The visual disconnecting device at the
surface substation for the underground high-voltage circuit at this
mine was not locked out or suitably tagged by the person performing
electrical work on this circuit on January 24, 2002. A general inside
laborer performed electrical work on the underground high-voltage
circuit without locking out or tagging the disconnecting device. The
disconnecting device at the surface is the only means to disconnect
the circuit. Also, electrical work was performed on a high-voltage
distribution circuit by a non-qualified person not under the direct
supervision of a qualified person at this mine. This resulted in fatal
injuries to the general inside laborer. The evening shift foreman and
electrician was the only qualified electrician at the mine. He was on
the surface during this procedure and was aware that the inside
laborer was performing electrical work. The inside laborer has not
been a qualified electrician since January 01, 1983
104(d)(1) Order No. 7323522 was issued March 6,
2002, for a violation of 30 CFR 75.705: The highvoltage lines supplying 12,470 VAC, three phase
power to the section power center located
underground at this mine were not grounded before
work was performed on them on January 24, 2002.
Ronnie Endicott, general inside laborer performed
electrical work on the underground high-voltage lines
without installing a grounding device that provides a
solid connection from the three power phases to the
system ground for the duration of the repair. No
protective grounding device was found, and
according to statements no such device had been
utilized by the electricians.
Best Practices
* Always lock and tag out before doing electrical work.
Electrical work shall be performed by a qualified electrician or
persons trained to do electrical work under the direct supervision of a
qualified electrician.
High voltage circuits must be grounded at all times while work is being
performed.
REASONS WHY PEOPLE DO NOT LOCKOUT
• They performed the job before or witnessed
someone else performing work without locking
out.
• The disconnecting device is too far away! Not
located where it is convenient for a person to use
• Worker pulled disconnect but did not lock it out
because they were by themselves and felt no
need to lockout.
• They do not want to shut down system, section,
plant, or operation for this minor repair.
SIX STEPS TO SAFETY
 Turn off the equipment and disconnect the energy source
 Lockout energy source ( electrical, mechanical,
pneumatic, hydraulic, etc. )
 Tag the disconnecting device ( danger person working on
equipment )
 Test the equipment to assure energy source is isolated
 Release energy in charged conductors, pipes, and etc
 Restore energy safely
LOCKOUT AND TAGOUT REGULATIONS
COAL
30 CFR § 75.511
No electrical work shall be performed on low-, medium-, or high-voltage distribution circuits
or equipment, except by a qualified person or by a person trained to perform electrical work
and to maintain electrical equipment under the direct supervision of a qualified person.
Disconnecting devices shall be locked out and suitably tagged by the persons who perform
such work, except that in cases where locking out is not possible, such devices shall be
opened and suitably tagged by such persons. Locks or tags shall be removed only by the
persons who installed them or, if such persons are unavailable, by persons authorized by the
operator or his agent.
30 CFR § 77.501
No electrical work shall be performed on electric distribution circuits or equipment, except
by a qualified person or by a person trained to perform electrical work and to maintain
electrical equipment under the direct supervision of a qualified person. Disconnecting
devices shall be locked out and suitably tagged by the persons who perform such work,
except that in cases where locking out is not possible, such devices shall be opened and
suitably tagged by such persons. Locks or tags shall be removed only by the persons who
installed them or, if such persons are unavailable, by persons authorized by the operator or
his agent.
METAL/NONMETAL
30 CFR § 56.12016 & 57.12016
Electrically powered equipment shall be deenergized before mechanical work is
done on such equipment. Power switches shall be locked out or other measures
taken which shall prevent the equipment from being energized without the
knowledge of the individuals working on it. Suitable warning notices shall be
posted at the power switch and signed by the individuals who are to do the work.
Such locks or preventive devices shall be removed only by the persons who
installed them or by authorized personnel.
30 CFR § 56.12017 & 57.12017
Power circuits shall be deenergized before work is done on such circuits unless
hot-line tools are used. Suitable warning signs shall be posted by the individuals
who are to do the work. Switches shall be locked out or other measures taken
which shall prevent the power circuits from being energized without the
knowledge of the individuals working on them. Such locks, signs, or preventative
devices shall be removed only by the person who installed them or by authorized
personnel.
30 CFR § 75.515
Cables shall enter metal frames of motors, splice boxes, and electric
compartments only through proper fittings. When insulated wires other
than cables pass through metal frames, the holes shall be substantially
bushed with insulated bushings.
30 CFR § 77.505
Cables shall enter metal frames of motors, splice boxes, and electric
compartments only through proper fittings. When insulated wires, other
than cables, pass through metal frames, the holes shall be substantially
bushed with insulated bushings.
30 CFR § 56.12008 & 56.12008
Power wires and cables shall be insulated adequately where they pass
into or out of electrical compartments. Cables shall enter metal frames of
motors, splice boxes, and electrical compartments only through proper
fittings. When insulated wires, other than cables, pass through metal
frames, the holes shall be substantially bushed with insulated bushings.
Wire:
only one conductor
covered by jacket .
Can be solid or
stranded.
30 CFR § 75.517
Power wires and cables, except trolley wires, trolley feeder wires, and
bare signal wires, shall be insulated adequately and fully protected.
30 CFR § 77.502
Electric equipment shall be frequently examined, tested, and properly
maintained by a qualified person to assure safe operating conditions.
When a potentially dangerous condition is found on electric equipment,
such equipment shall be removed from service until such condition is
corrected. A record of such examinations shall be kept.
30 CFR § 56.12004 & 57.12004
Electrical conductors shall be of a sufficient size and current-carrying
capacity to ensure that a rise in temperature resulting from normal
operations will not damage the insulating materials. Electrical conductors
exposed to mechanical damage shall be protected.
30 CFR § 75.514
All electrical connections or splices in conductors shall be mechanically and electrically
efficient, and suitable connectors shall be used. All electrical connections or splices in
insulated wire shall be reinsulated at least to the same degree of protection as the
remainder of the wire.
30 CFR § 77.504
Electrical connections or splices in electric conductors shall be mechanically and
electrically efficient, and suitable connectors shall be used. All electrical connections or
splices in insulated wire shall be reinsulated at least to the same degree of protection as
the remainder of the wire.
30 CFR § 56.12013
Permanent splices and repairs made in power cables, including the ground conductor
where provided, shall be:
(a) Mechanically strong with electrical conductivity as near as possible to that of the
original;
(b) Insulated to a degree at least equal to that of the original, and sealed to exclude
moisture; and
(c) Provided with damage protection as near as possible to that of the original, including
good bonding to the outer jacket.
75.514
All electrical connections or splices in conductors shall be mechanically and
electrically efficient, and suitable connectors shall be used. All electrical
connections or splices in insulated wire shall be reinsulated at least to the same
degree of protection as the remainder of the wire. Policy
75.901
(a) Low- and medium-voltage three-phase alternating-current circuits used
underground shall contain either a direct or derived neutral which shall be grounded
through a suitable resistor at the power center, and a grounding circuit, originating at
the grounded side of the grounding resistor, shall extend along with the power
conductors and serve as a grounding conductor for the frames of all the electrical
equipment supplied power from that circuit, etc. Policy
75.514
All electrical connections
or splices in conductors
shall be mechanically and
electrically efficient, and
suitable connectors shall
be used. All electrical
connections or splices in
insulated wire shall be
reinsulated at least to the
same degree of protection
as the remainder of the
wire. Policy
75.517
75.810
Power wires and cables,
except trolley wires, trolley
feeder wires, and bare signal
wires, shall be insulated
adequately and fully
protected. Policy
In the case of high-voltage cables used as trailing
cables, temporary splices shall not be used and all
permanent splices shall be made in accordance
with §75.604. Terminations and splices in all other
high-voltage cables shall be made in accordance
with the manufacturer's specifications. No policy