Electrical_Safety_1711951651ruehdnejdjrjdjeke

SHIFANA OTTATHAIKAL KAREEM
https://www.linkedin.com/in/shifana-ok
ELECTRICAL
SAFETY
Created By:
SHIFANA
OTTATHAIKAL
KAREEM

ELECTRICAL HAZARDS
Electrical Shock
The effects of electric current on the body depend on various factors:
Current's pathway
through the body
Energy deposited
into the body
Amount of
current
Waveform of the current
(eg., DC, AC, RF, Impulse)
Duration of
shock
Shock occurs when electrical current flows
through any part of a worker's body from an
external source, potentially resulting in
serious injury or death.
Most electrical systems establish a voltage
reference point by connecting to an earth
ground.
Workers in contact with earth and exposed
conductors face a shock hazard.
Contact with an energized conductor and a
grounded object creates an alternate path
for current through the body.
Safety features in electrical equipment
typically protect workers from shock under
normal conditions.

The amount of current passing through the body
depends on:
Environmental
Conditions
Voltage driving
the current
Contact resistance
and internal body
resistance
Frequency of
the current
Circuit
characteristics
The heart and brain are the
most vulnerable to electric
shock.
Currents exceeding 75 mA
lead to ventricular fibrillation,
causing death within minutes
without a defibrillator.
Heart paralysis occurs at 4
amps, resulting in no
pumping action.
Tissue burns occur with
currents surpassing 5 amps.
ELECTRICAL HAZARDS
Electrical Shock

There are five principal electrical waveforms of interest that cause various responses to electrical
shock:
Alternating
Current
Response
Direct Current
Response
The most dangerous are AC power frequencies, typically 60 hertz (Hz).
Exposure to current at these frequencies causes ventricular fibrillation at
the lowest thresholds and causes severe contraction of the muscles with a
possible no-let-go response
DC electric currents can prompt muscle response upon contact and
release, along with heart fatigue and failure at high levels.
Low levels of DC current don't induce muscle paralysis or pose hazards
like let-go threshold, respiratory paralysis, or fibrillation.
Prolonged exposure to DC current can lead to fatal internal tissue
burning.
Alternating Current
Power Frequencies
Direct Current Sub radio frequencies
(sub RF) 1 Hz – 3 kHz
Radio frequencies
(RF) 3 kHz – 100
MHz
Impulse shock
(such as from a
capacitor circuit)
ELECTRICAL HAZARDS
Electrical Shock

Capacitor
Response
Capacitors can deliver an impulse shock to the body, with damage
influenced by voltage, total energy discharged, and deposition time.
Fast, high-energy discharges can trigger heart fibrillation, while lower
voltages with increased skin resistance usually lengthen discharge time
and decrease risk.
Radio
Frequency
Waveforms
Radiofrequency waveforms (5 kilohertz (kHz) to 100 megahertz (MHz))
have decreasing neurological effects with increasing frequency, but
energy deposited results in tissue burning.
Skin breakdown by high-voltage shocks lowers body
resistance, increasing current flow and damage.
Reflex action severity, heart damage, and tissue
effects depend on current amount and duration.
Internal body resistance, usually 1000 Ohms, can
drop to 200 Ohms.
Body Resistance
ELECTRICAL HAZARDS
Electrical Shock

LEVELS OF EFFECT OF ELECTRIC CURRENT

The most common shock-related, nonfatal
injury is a burn.
Burns caused by electricity may be of three
types:
Electrical
Current
Burn
Thermal
Contact
Burn
Arc Blast Burn
ELECTRICAL HAZARDS
Electrical burn
In electrical current burns, tissue damage
(whether skin-level or internal) occurs
because the body is unable to dissipate
the heat from the current flow.
Electrical current burns are slow to heal.
Thermal contact burns occur when skin
touches overheated electrical conductors,
including tools and jewelry, due to
proximity to a high-current source.
Controls to prevent shock and arc flash
should also protect against thermal burns
from low-voltage/high-current systems.
Thermal burns may result if an explosion
occurs when electricity ignites an
explosive mixture of material in the air.
This ignition can result from the buildup of
combustible vapors, gases, or dusts.

Arc-blasts occur when
powerful, high-amperage
currents arc through the air.
Electric arcs can melt nearby
material, vaporize metal,
and cause flesh burns and
clothing ignition.
ELECTRICAL
HAZARDS
Arc flash burn
They can occur in stable low-
voltage arcs or short-circuit
arcs at higher voltage.
There are five types of arc flash:
ARC IN OPEN AIR
Mainly emits infrared radiation and occurs on
power lines in front of workers.
The gases are expanding in relatively all directions
equally at once like a sphere.
ARC IN A BOX
Arc in a box is more dangerous than open-air arcs
as energy is concentrated in a focused path, often
straight out the doors where workers stand.
This type is common in industrial electrical
equipment like MCCs, panelboards, and
switchgear.

ARC PLASMA CONVECTIVE FLOW
Sustained arc flash driven by magnetic forces
propels plasma towards busbar tips away from the
power source.
Plasma forcefully ejects in a highly directional
flow, potentially redirected by metal surfaces.
HV SKIN SURFACE TRACKING ARC
During a high voltage shock, a tracking arc may
occur where current flows along or just above the
skin, bypassing the body.
Unlike metal plasma arcs, this type only causes
thermal burns from the arc itself.
An arc is initiated on
uninsulated lines or
busbar and travels away
from the source.
TRAVELING ARC
ELECTRICAL HAZARDS
Arc flash burn

The hazards associated with various types of
batteries and battery banks include
Chemical burns
from electrolyte
spills or from
battery surface
contamination
Electric shock;
Burns & shrapnel-
related injuries
from a short
circuit
Physical injury
from lifting or
handling the
cells
ELECTRICAL HAZARDS
Arc blast hazards
Rapid electrical energy delivery into
an arc can create hazards beyond arc
flash.
The arc blast pressure wave can
burst eardrums
at lower levels
cause cardiac arrest
at higher levels.
High currents (> 100 kA) can generate
strong magnetic forces, leading to
equipment destruction or conductor
whipping.
Battery hazards
When working on batteries or battery banks,
both electrical and physical hazards must be
considered.
Additionally, when working near flooded lead-
acid storage batteries, chemical and explosion
hazards should also be taken into account.
Fire /explosion
due to H2;
overheated
electrical
components
SHIFANA
OTTATHAIKAL
KAREEM

The value that follows "-" is up to and includes that value.
For example, over 50-200 kV means up to and include 200 kV.
0-50 kV
Min. distance
10 ft.
50-200 kV
Min. distance
15 ft.
ELECTRICAL PROTECTION METHODS
Maintain safe distance from overhead power lines
The following image shows the safe power line clearence distance for various line
voltages:
200-350 kV
Min. distance
20 ft.
350-500 kV
Min. distance
25 ft.
500-750 kV
Min. distance
35 ft.
750-1000 kV
Min. distance
45 ft.

2023
The minimum distance for
voltages up to 50kV is
Risks
Contact with Overhead Powerlines
Overhead powerlines are usually not insulated.
Overhead and buried powerlines carry
extremely high voltage
Electrocution (Main Risk)
Burns & Falls
When dump trucks, cranes, work
platforms, or other conductive materials
(such as pipes and ladders) contact
overhead wires, the equipment operator or
other workers can be killed.
The covering on an overhead powerline is
primarily for weather protection.
Hence, workers must know that if they touch a
powerline covered or bare, death is probable.
For voltages over 50kV,
the minimum distance is
10 feet
10 feet + 4 in
for every 10 kV
over 50kV.

Contact with Overhead Powerlines
Always conduct a risk assessment to
identify nearby overhead power lines
before starting work.
Ensure machinery, people, or equipment
stay at safe distances from power lines,
typically 4 meters for overhead lines
and 6 meters for transmission lines.
Employ controls to minimize risks if
elimination isn't possible.
Regularly review and update your risk
plan for working near overhead power
lines.
What to do?
If equipment contacts a powerline
and you're in danger:
Jump away from the equipment,
landing with both feet together.
Hop or shuffle with feet together
to reduce electric shock risk.
Stay clear until declared safe by
the utility company.
Call emergency services.

GROUND FAULT CIRCUIT INTERRUPTERS (GFCI'S)
GFCI is not an overcurrent
device like a fuse or circuit
breaker.
GFCI's are designed to sense
an imbalance in current flow
over the normal path.
GFCI contains a special sensor
that monitors the strength of
magnetic field around each
wire in the circuit when current
is flowing.
The field is proportional to the
amount of current flow.
If the current flowing in the black (ungrounded) wire is
within 5 mA of the current flowing in the white
(grounded) all the current will flow in the normal path.
If the current flow differs by more
than 5 mA +/- 1 mA, GFCI will
quickly open the circuit.

Inspect portable tools and
extension cords
Workers need to inspect extension cords prior
to their use for any cuts or abrasion.
Extension cords may have damaged insulation.
Sometimes an insulation inside the electrical
tool or appliance is damaged.
Electric hand tools that are old,damaged or
misused may have damaged insulation inside.
When it happens exposed metal parts may
become energized if live wire inside touches
the metal parts.
Identification of
power source
Mark all breakers accordingly for the
circuits they protect.
Make sure that all disconnect means are
marked accordingly for the equipment they
service.
Make sure that all voltages are identified
with proper labelling.

Using equipment outdoors
that is labeled for use only
in dry indoor locations
Using multi-receptable
boxes designed to be
mounted by fitting them
with a power cord and
placing them on the floor.
Common examples of misused equipment.
Fabricating extension
cords with ROMEX wire.
Use power tools and equipment as
designed
Follow tool safety tips to avoid misusing
equipment.
Follow manufacturers instructions.
Tool Safety Tips
Never carry a tool by the cord.
Never yank the cord to disconnect it.
Keep cords away from heat, oil &
sharp edges.
Disconnect when not in use & when
changing accessories such as blades
& bits.
Avoid accidental starting. Do not hold
fingers on the switch while carrying a
plugged in tool.
Don't use in wet/ damp conditions.
Ensure that cords do not cause tripping
hazard.
Use double insulated tools.
Remove damaged tools from use.

Attaching ungrounded two prong
adapter plugs to three prong cords and
tools.
Common examples of misused equipment.
Using circuit breakers or fuses with wrong
rating for over current protection
Eg., Using 30 mA breaker in a system with
15/ 20 mA receptables. Protection is lost
because it will not trip when the system's load
has been exceeded.
Use power tools and equipment as designed
Tool Safety Tips
Use gloves and appropriate footwear.
Keep working in areas well lit.
Store in a dry place when not using
Using cords or tools with worn insulation
or exposed wires.
Using modified cords or tools i.e., ground prongs removed, face plates, insulations etc.

Follow Lockout/ Tagout (LOTO)
procedures:
Essential safety procedure.
Protects workers from injury while
working on or near electrical circuits
and equipment.
Prevents contact with operating
equipment parts such as blades,
gears, shafts etc.
Prevents unexpected release of
hazardous gases, fluids or solid
matter in areas where workers are
present.
When performing LOTO on circuits and equipment,
you can use the checklist below:
Identify all energy sources.
Disable backup energy sources like generators
and batteries.
Shut off all energy sources.
Notify personnel to shut off, lock and tag
equipment and circuitry.
Lock switchgear in the OFF position, with each
worker using their individual lock.
Test equipment to ensure it's de-energized, done
by a qualified person.
Deplete stored energy (e.g., capacitors).
Ensure everyone is safe before unlocking and re-
energizing circuits, determined by a qualified
person.
Apply a tag to indicate equipment is locked out.

Keep the victim warm and
talk to them until help
arrives.
Turn off the electricity if the
victim is in contact with the
circuit and have someone call
for help.
WHAT SHOULD I DO IF A CO WORKER IS
SHOCKED OR BURNED BY ELECTRICITY?
Use a non-conductive object
to remove the victim from the
circuit if you can't reach the
switchgear quickly.
Avoid touching the victim
yourself.
Stay with the victim until
emergency medical services
(EMS) arrive.
If conscious, advise the
victim not to move and
check for major bleeding.
Apply pressure and elevate
the injured area if needed.
If unconscious, check for
breathing and perform CPR
if necessary within 4
minutes of the shock.
If not trained in CPR or first aid, consider getting certified.
Know the location of electricity shut-offs, first-aid supplies,
and a telephone for emergencies. SHIFANA OTTATHAIKAL KAREEM

SHIFANA
OTTATHAIKAL
KAREEM
FOR YOUR ATTENTION
THANK YOU
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