Transcript Electrical Safety: Qualified Person

Electrical SafetyQualified Person
Energized exposed
electrical parts
 Exposed
parts
 Live
or energized
parts
 De-energized
parts
1a
Energized exposed
electrical parts
 Exposed
parts that are deenergized, but not
locked/tagged are considered
energized, exposed parts
1b
Working near exposed
parts
 Only
qualified workers can work
on or near exposed electrical
parts
2a
Working near exposed
parts
 Live
parts operating at less than
50 volts to ground do not need
to be de-energized when:
• the worker experiences no
increased exposure to electrical
burns or explosions due to
electrical arcs
2b
Working near exposed
parts
 Lockout/tagout
must be
performed by a qualified person
 Who
is considered a
qualified person?
2c
Working near exposed
parts
 Types
work:
of excluded electrical
• general, transmission, distribution
installations
• communications installations
• vehicle installations
• railway installations
2d
Distinguishing exposed live
parts from other parts
 Qualified
persons use voltage
testing equipment to identify
live and de-energized parts
 Testing
equipment must be
rated for the anticipated
voltages to be tested
3a
Nominal voltage of
exposed live parts
 Nominal
voltages are values
assigned to circuits to
designate its voltage class
• 120/240
• 480Y/277
• 600
4a
Nominal voltage of
exposed live parts
 The
actual voltage at which a
circuit operates can vary from
the nominal within a range that
permits satisfactory operation
 Multi-meters/volt-ohm
identify voltage
meters
4b
Clearance distances -
Unguarded/energized
overhead lines
 The
required
distance
between the
workers and a
conductive
object that
they could
contact
5a
Clearance distances -
Unguarded/energized
overhead lines
 Used
when
working
below
unguarded,
energized
lines
5b
Clearance distances -
Unguarded/energized
overhead lines
Exceptions to required distances:
 The worker is wearing insulated
equipment
5c
Clearance distances -
Unguarded/energized
overhead lines
Exceptions to required distances:
 The energized part is insulated
from the worker, and all
conductive parts at a different
potential
5d
Clearance distances -
Unguarded/energized
overhead lines
Exceptions to required distances:
 The worker is insulated from all
conductive objects at a
different potential than the
energized part
5e
Clearance distances -
overhead lines and
vehicles/equipment
 Voltages
50 kv or less, the
clearance distance is 10 feet
 Voltages
greater than 50kv, the
clearance is 10 feet plus 4
inches for every 10 kv over 50
kv
6a
Clearance distances -
overhead lines and
vehicles/equipment
 When
the vehicle is in transit,
and the structure is lowered:
• the clearance distance is 4 feet for
50 kv or less; or
• 4 feet plus 4 inches for every 10 kv
over 50 kv for voltage greater than
50 kv
6b
Clearance distances -
overhead lines and
vehicles/equipment
 Insulating
barriers
• When installed but not attached to
a vehicle, the clearance distance
is the designed working
dimensions of the barrier
 Refer
to Table S-5 for aerial lift
clearance distances
6c
Clearance distances -
overhead lines and
vehicles/equipment

Employees must not come into
contact with vehicles/equipment
under an energized line unless
the:
• employee is wearing proper PPE
• equipment/vehicle is located so that
no uninsulated part can provide a
conductive path to employees
6d
Clearance distances -
overhead lines and
vehicles/equipment
 Do
not stand near grounding
locations for intentionally
grounded equipment/vehicles
when contact with overhead
wires is possible
• Insulation and barriers
6e
Illumination
 Do
not enter an area containing
exposed energized parts unless
the area is illuminated
 Do
not work near exposed
energized parts unless the area
is properly illuminated
 Do
not reach into blind areas
7a
Confined spaces
 Barriers,
shields, and insulation
provide protection from
energized parts
 Secure
doors, hinged panels to
prevent exposure to energized
parts
8a
Handling conductive
materials/equipment
 Carefully
handle conductive
materials or equipment that
come in contact with your body
 Prevent
contact with exposed
energized parts
9a
Handling conductive
materials/equipment
 Carefully
handle long,
conductive objects in areas
containing exposed energized
parts
• Insulation
• Guarding
• Materials handling
9b
Nonconductive ladders
 Portable
ladders must have
nonconductive siderails if they
could contact exposed
energized parts
 Metal
ladders can conduct
electricity and cause arcing and
shocks
10a
Hazards of conductive
apparel
 Conductive
jewelry and clothing
can cause arcing when exposed
to energized parts
 Remove
or cover conductive
jewelry and clothing to
eliminate risk of conductivity
11a
Procedures for using
portable electrical
equipment
12a
Proper handling of cords
 Don’t
raise or lower equipment
by its cord
 Don’t
unplug the equipment by
pulling on its cord
 Don’t
staple or fasten the cord
so as to damage outer jacket
12b
Equipment inspection
 Visually
check for:
• loose parts
• deformed or missing parts
• damaged jackets or insulation
 Inspect
for internal defectives,
such as pinched or crushed
outer jackets
12c
Equipment inspection
 Perform
inspections prior to
beginning each shift
 Remove
defective equipment
from service
 Check
the plug and receptacle
mating configuration before
connecting
12d
Flexible cords
 Flexible
cords with groundingtype of equipment must have an
equipment grounding conductor
12e
Flexible cords
 Never
remove or alter the cord’s
grounding pin
 Never
use an adapter with a
missing grounding pin
12f
Types of electrical
equipment and cords
to be used near water
12g
Proper methods for
plugging/unplugging
 Ensure
hands are dry
 Never
pull the
plug out by the
cord
12h
Proper methods for
plugging/unplugging
 Handle
cords and equipment
with insulating protective
equipment when the cord
connector is wet
 Secure
locking-type connectors
after making connection
12i
Circuit breakers and
circuits
 Never
use the following to open
and close electrical circuits
•
•
•
•
Fuses
Terminal lugs
Cable connectors
Cable splice connections
13a
Circuit breakers and
circuits
 Don’t
manually re-energize a
circuit without first determining
if the equipment and circuit can
be safely energized
 Don’t
modify overcurrent
protective devices
13b
Circuit breakers and
circuits
 Testing
of electrical equipment
should be performed by
qualified persons only
 Keep
flammables and
combustibles away from
electrical equipment
13c
Protective equipment
 Personal
includes:
•
•
•
•
•
protective equipment
Headgear
Eye and face protection
Rubber insulating gloves
Rubber insulating sleeves
Protective footwear
14a
Protective equipment
 Inspect
protective equipment to
ensure its reliability and safety
 Use
insulated
tools/equipment
around exposed
energized parts
14b
Protective equipment
 Protective
shields, barriers,
insulating materials protect
employees from:
• accidental contact
• dangerous
electrical
heating
• arcing
14c
Protective equipment
 Normally
enclosed live parts
must be guarded during
maintenance
14d
Alerting techniques
 Signs
and markings
 Barricades
 Attendants
15a
Summary of key points
 Definitions
 De-energized
means
locked/tagged out
 Safe
distances for clearances
between workers and energized
lines
16a
Summary of key points
 Nonconductive
ladders
 Nonconductive
clothing
 Proper
use of cords, plugs,
receptacles
16b
Summary of key points
 Proper
use of electrical
equipment around
flammables/combustibles
 Protective
 Alerting
equipment
techniques
16c